阅读说明：本技术 黑色氧化锆陶瓷及其制备方法和应用 (Black zirconia ceramic and preparation method and application thereof ) 是由 陈戈 林信平 唐威 于 2019-09-23 设计创作，主要内容包括：本发明涉及氧化锆陶瓷领域,公开了一种黑色氧化锆陶瓷及其制备方法和应用。所述氧化锆陶瓷以元素计包含：Zr、Y、Si、Al、Zn、Co、Ni、Mn、Mg、Fe、Cr,以及Nb和/或Ta,且所述氧化锆陶瓷的物相包含：四方相氧化锆、ZrSiO-4和尖晶石黑色料,所述尖晶石黑色料的化学式表示为[Co-eNi-fMn-gZn-hMg-((1-e-f-g-h))][Fe-xCr-yAl-((1-x-y))]-2O-4,其中,0≤e≤1,0≤f≤1,0≤g≤1,0≤h≤0.5,0.5≤e+f+g≤1；0≤x≤1,0≤y≤1,0＜x+y≤1；所述四方相氧化锆为氧化钇、氧化铌和/或氧化钽与氧化锆形成的固溶体。该黑色氧化锆陶瓷可以同时具有介电常数小于29,密度低于5.7g/cm～3,减薄速度大于40丝/h,落锤高度大于27cm的特点,综合性能好于现有技术的陶瓷。(The invention relates to the field of zirconia ceramics, and discloses black zirconia ceramics and a preparation method and application thereof. The zirconia ceramic comprises, in elemental terms: zr, Y, Si, Al, Zn, Co, Ni, Mn, Mg, Fe, Cr, and Nb and/or Ta, and the phase of the zirconia ceramic comprises: tetragonal phase of zirconium oxide or ZrSiO 4 And spinel black pigment, the spinel black pigment having a chemical formula of [ Co e Ni f Mn g Zn h Mg (1‑e‑f‑g‑h) ][Fe x Cr y Al (1‑x‑y) ] 2 O 4 Wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1;the tetragonal zirconia is a solid solution formed by yttria, niobia and/or tantalum oxide and zirconia. The black zirconia ceramic can simultaneously have a dielectric constant of less than 29 and a density of less than 5.7g/cm 3 The thinning speed is more than 40 threads/h, the drop weight height is more than 27cm, and the comprehensive performance is better than that of the ceramic in the prior art.)

1. A black zirconia ceramic, the zirconia ceramic comprising, on an elemental basis: zr, Y, Si, Al, Zn, Co, Ni, Mn, Mg, Fe, Cr, and Nb and/or Ta, and the phase of the zirconia ceramic comprises: tetragonal phase of zirconium oxide or ZrSiO₄And spinel black pigment, the spinel black pigment having a chemical formula of [ Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄Wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1; the tetragonal zirconia is a solid solution formed by yttria, niobia and/or tantalum oxide and zirconia.

2. The ceramic of claim 1, wherein the zirconia ceramic comprises, on an elemental basis: 45.4-63 wt% Zr, 1.85-4.85 wt% Y, 1.2-4.8 wt% Si, 0-5 wt% Al, 0-3 wt% Zn, 0-5.3 wt% Co, 0-5.3 wt% Ni, 0-5.1 wt% Mn, 0-1.22 wt% Mg, 0-8.3 wt% Fe, 0-8 wt% Cr, 0.7-2.8 wt% Nb and/or Ta;

preferably comprising: 48.2-60.5 wt.% Zr, 2-4.5 wt.% Y, 2.2-4.2 wt.% Si, 1.5-5.2 wt.% Al, 0-1.2 wt.% Zn, 0.7-2.3 wt.% Co, 0.7-2.3 wt.% Ni, 0.7-2.3 wt.% Mn, 0-0.46 wt.% Mg, 1.2-2.9 wt.% Fe, 0.17-1.2 wt.% Cr, 1.4-2.4 wt.% Nb and/or Ta.

3. The ceramic of claim 1 or 2, wherein the zirconia ceramicThe phase of the porcelain comprises: 48.9-84.8 wt% of tetragonal zirconia and 7.8-31.7 wt% of ZrSiO₄5.9-15.9 wt% of the spinel black pigment;

preferably comprising: 54.9-77.7 wt% of tetragonal zirconia and 14.7-27.9 wt% of ZrSiO₄7.8-14.9 wt% of spinel black pigment.

4. The ceramic according to any one of claims 1 to 3, wherein the zirconia ceramic has a dielectric constant of 20 to 29 and a density of not more than 5.7g/cm³The thinning speed of the zirconia ceramic is more than 40 wires/h, and the average drop weight height of the zirconia ceramic is more than 27 cm.

5. A preparation method of black zirconia ceramic comprises the following steps:

(1) wet grinding powder containing spinel black pigment, niobium oxide and/or tantalum oxide, zirconium oxide, yttrium oxide and silicon dioxide by adding water, a dispersing agent and a binder to obtain slurry;

(2) drying the slurry to obtain composite zirconia powder;

(3) forming the composite zirconia powder, and then sintering in air to obtain ceramic;

wherein the spinel black pigment has a chemical formula as follows:

[Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1.

6. The production method according to claim 5, wherein the powder contains 1 to 4 wt% of niobium oxide and/or tantalum oxide, 6 to 16 wt% of spinel black pigment, 8 to 32 wt% of zirconium silicate, 48 to 84 wt% of zirconium oxide, and 2 to 4 mol% of yttrium oxide, based on the total amount of the powder;

preferably, the powder contains 2.1-3.6 wt% of niobium oxide and/or tantalum oxide, 8-15 wt% of spinel black pigment, 15-28 wt% of zirconium silicate, 53-74.5 wt% of zirconium oxide, and the zirconium oxide contains 2-4 mol% of yttrium oxide.

7. The preparation method according to claim 5 or 6, wherein in the step (1), the dispersant is selected from at least one of hypromellose, sodium carboxymethylcellulose, and triethanolamine;

preferably, the addition amount of the dispersing agent is 0.005-0.5 wt% of the powder, and preferably 0.01-0.1 wt%.

8. The production method according to any one of claims 5 to 7, wherein the binder is selected from polyvinyl alcohol and/or polyethylene glycol;

preferably, the addition amount of the binder is 0.5-5 wt% of the powder, preferably 2-5 wt%.

9. The production method according to any one of claims 5 to 8, wherein, in the step (3),

the sintering procedure comprises: raising the temperature from room temperature to 600 ℃ for 400min and preserving heat for 2h, raising the temperature from 600 ℃ to 1150 ℃ for 300min and preserving heat for 2h, raising the temperature from 1150 ℃ to 1300 ℃ for 150min and preserving heat for 2h, raising the temperature from 1300 ℃ to 1350 ℃ and 1450 ℃ for 1-2h, then reducing the temperature to 900 ℃ for 150min, and finally naturally cooling to room temperature.

10. A black zirconia ceramic produced by the production method according to any one of claims 5 to 9.

11. Use of the black zirconia ceramic of any one of claims 1 to 3 and 10 in the preparation of a back cover for a cellular phone.

Technical Field

The invention relates to the field of zirconia ceramics, in particular to black zirconia ceramics and a preparation method and application thereof.

Background

The zirconia ceramics have the characteristics of good corrosion resistance, high hardness and high strength of the conventional ceramics, so the zirconia ceramics have wide application. The toughness (reaching 5-6MPa m)^1/2) Although higher than other conventional ceramics, the ceramic has a disadvantage of weak impact resistance when formed into a large-area appearance. In addition, when a rear cover product of a cellular phone is manufactured, there are problems of heavy weight due to high density and signal transmission due to high dielectric constant. In order to solve the problems, some manufacturers reduce the density and the dielectric constant by adding more aluminum oxide, but the high hardness and the high brittleness of the aluminum oxide can cause the processing difficulty to be greatly increased, so that the yield is low, the cost is high, and the production is impossible. Therefore, it is very important to develop a zirconia ceramic having low dielectric constant, low density, high impact resistance and good processability for the application of the ceramic rear cover in the 5G era.

Disclosure of Invention

The invention aims to solve the problems of improving the dielectric constant, the impact resistance, the processability and the density of zirconia ceramics, and provides black zirconia ceramics and a preparation method and application thereof.

In order to achieve the above object, a first aspect of the present invention provides a black zirconia ceramic comprising, in terms of elements: zr, Y, Si, Al, Zn, Co, Ni, Mn, Mg, Fe, Cr, and Nb and/or Ta, and the phase of the zirconia ceramic comprises: tetragonal phase of zirconium oxide or ZrSiO₄And spinel black pigment, the spinel black pigment having a chemical formula of [ Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄Wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1; the tetragonal zirconia is a solid solution formed by yttria, niobia and/or tantalum oxide and zirconia.

Preferably, the zirconia ceramic comprises, in elemental terms: 45.4-63 wt% Zr, 1.85-4.85 wt% Y, 1.2-4.8 wt% Si, 0-5 wt% Al, 0-3 wt% Zn, 0-5.3 wt% Co, 0-5.3 wt% Ni, 0-5.1 wt% Mn, 0-1.22 wt% Mg, 0-8.3 wt% Fe, 0-8 wt% Cr, 0.7-2.8 wt% Nb and/or Ta.

Preferably, the phase of the zirconia ceramic comprises: 48.9-84.8 wt% of tetragonal zirconia and 7.8-31.7 wt% of ZrSiO₄5.9-15.9 wt% of the spinel black pigment.

Preferably, the dielectric constant of the zirconia ceramic is 20 to 29, and the density of the zirconia ceramic is not more than 5.7g/cm³。

The second aspect of the present invention provides a method for preparing a black zirconia ceramic, comprising:

(1) wet grinding powder containing spinel black pigment, niobium oxide and/or tantalum oxide, zirconium oxide, yttrium oxide and silicon dioxide by adding water, a dispersing agent and a binder to obtain slurry;

(2) drying the slurry to obtain composite zirconia powder;

(3) forming the composite zirconia powder, and then sintering in air to obtain ceramic;

wherein the spinel black pigment has a chemical formula as follows:

[Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1.

In a third aspect of the present invention, there is provided a black zirconia ceramic obtained by the production method of the present invention.

The fourth aspect of the invention provides the application of the black zirconia ceramic in the preparation of the back shell of a mobile phone.

Through the technical scheme, the zirconia ceramic contains various metal elements and a special phase structure, can provide black zirconia ceramic, and has low dielectric constant and good decomposition effectThe problems of impact resistance, processability and density of the zirconia ceramic are solved. The zirconia ceramic can simultaneously have a dielectric constant of less than 29 and a density of less than 5.7g/cm³The thinning speed is more than 40 wires/h, the average drop weight height is more than 27cm, and the comprehensive performance is better than that of the ceramic in the prior art.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The present invention provides, in a first aspect, a black zirconia ceramic comprising, in terms of elements: zr, Y, Si, Al, Zn, Co, Ni, Mn, Mg, Fe, Cr, and Nb and/or Ta, and the phase of the zirconia ceramic comprises: tetragonal phase of zirconium oxide or ZrSiO₄And spinel black pigment, the spinel black pigment having a chemical formula of [ Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄Wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1; the tetragonal zirconia is a solid solution formed by yttria, niobia and/or tantalum oxide and zirconia.

The zirconia ceramic provided by the invention contains the multiple elements and phase structures, has pure black color, and can realize low dielectric constant and light weight of the ceramic.

According to an embodiment provided by the present invention, preferably, the zirconia ceramic contains, in terms of elements: 45.4-63 wt% Zr, 1.85-4.85 wt% Y, 1.2-4.8 wt% Si, 0-5 wt% Al, 0-3 wt% Zn, 0-5.3 wt% Co, 0-5.3 wt% Ni, 0-5.1 wt% Mn, 0-1.22 wt% Mg, 0-8.3 wt% Fe, 0-8 wt% Cr, 0.7-2.8 wt% Nb and/or Ta. The elemental composition can be tested by XRF using an energy dispersive X-ray fluorescence spectrometer EDX-7000. Preferably, the zirconia ceramic comprises, in elemental terms: 48.2-60.5 wt.% Zr, 2-4.5 wt.% Y, 2.2-4.2 wt.% Si, 1.5-5.2 wt.% Al, 0-1.2 wt.% Zn, 0.7-2.3 wt.% Co, 0.7-2.3 wt.% Ni, 0.7-2.3 wt.% Mn, 0-0.46 wt.% Mg, 1.2-2.9 wt.% Fe, 0.17-1.2 wt.% Cr, 1.4-2.4 wt.% Nb and/or Ta. The elements in the zirconia ceramic may contain other elements, such as oxygen, in addition to the above metals. The sum of the contents of all elements is about 100 wt%.

According to the invention, particular phases are present in the zirconia ceramic, which can be determined by XRD. Preferably, the phase of the zirconia ceramic comprises: 48.9-84.8 wt% of tetragonal zirconia and 7.8-31.7 wt% of ZrSiO₄5.9-15.9 wt% of the spinel black pigment; preferably comprising: 54.9-77.7 wt% of tetragonal zirconia and 14.7-27.9 wt% of ZrSiO₄7.8-14.9 wt% of spinel black pigment. In an XRD spectrum, diffraction peaks of tetragonal phases of zirconia appear, and it is possible that yttria, niobia and/or tantalum oxide are added in the preparation of the zirconia ceramic to form a solid solution with zirconia. Preferably, the material may be a solid solution of yttrium oxide, niobium oxide and zirconium oxide, a solid solution of yttrium oxide, tantalum oxide and zirconium oxide, or a solid solution of yttrium oxide, niobium oxide, tantalum oxide and zirconium oxide. The zirconia ceramic may also contain other phases, but does not adversely affect the zirconia ceramic of the present invention. In the present invention, the content of the phase contained in the zirconia ceramic is based on the zirconia ceramic.

When the element composition and the phase structure of the zirconia ceramic provided by the invention contain the above composition, the dielectric property and the density of the zirconia ceramic are improved.

In the present invention, although the effects that may be brought about by the addition of each of the various oxides may be considered, for example, yttria, niobia, and/or tantala may have the effect of stabilizing, toughening zirconia. However, in the invention, the spinel black material is added into the black zirconia ceramic composition, not only can be used for developing color, but also can be matched with other components, thereby bringing the effect of reducing the density and the dielectric constant of the zirconia ceramic, and simultaneously obtaining the improvement of dielectric property, density, impact resistance and processability. Outside the above-defined range, the obtained zirconia ceramic cannot have the dielectric constant, density, impact resistance and processability which the zirconia ceramic provided by the present invention has at the same time.

The zirconia ceramic provided by the invention is pure black, has low dielectric constant, is reduced in density, and realizes light weight. Preferably, the dielectric constant of the zirconia ceramic is 20 to 29, and the density of the zirconia ceramic is not more than 5.7g/cm³The thinning speed of the zirconia ceramic is more than 40 wires/h, and the average drop weight height of the zirconia ceramic is more than 27 cm.

In the invention, the provided zirconia ceramic has the toughness of 7-12.5MPa m^1/2. It can be seen that the zirconia ceramic has good toughness.

In the invention, in the result of the falling weight impact test of the zirconia ceramic, the average falling weight height is more than 27cm, and the average falling weight height is preferably 27-30 cm. It can be seen therefrom that the zirconia ceramic can have high impact resistance.

In the present invention, the measurement of the reduction rate of the zirconia ceramic reflects the workability of the ceramic. The thinning speed is 40-50 filaments/h. The faster the copper plate is thinned, the faster the processing speed is, the higher the efficiency is in production, and the lower the cost is. As can be seen, the zirconia ceramic may have good workability.

The zirconia ceramic provided by the invention has high impact resistance, low dielectric constant and low density, and simultaneously has better processability.

The second aspect of the present invention provides a method for preparing a black zirconia ceramic, comprising: (1) wet grinding powder containing spinel black pigment, niobium oxide and/or tantalum oxide, zirconium oxide, yttrium oxide and silicon dioxide by adding water, a dispersing agent and a binder to obtain slurry; (2) drying the slurry to obtain composite zirconia powder; (3) forming the composite zirconia powder, and then sintering in air to obtain ceramic;

wherein the spinel black pigment has a chemical formula as follows:

[Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1.

In the present invention, the powders of niobium oxide, tantalum oxide, zirconium oxide, yttrium oxide, spinel black pigment, and silica may be provided individually or in combination as a high-purity powder. For example, the yttrium oxide and zirconium oxide can be prepared by using a zirconium oxide powder containing 2 to 4 mol% of yttrium oxide (median particle diameter of 0.3 to 0.6 μm, specific surface area of 7 to 13 m)²In terms of/g). Niobium oxide can be niobium pentoxide (with a median particle size of 8-10 μm) powder. The tantalum oxide can be tantalum pentoxide powder (with a median particle size of 8-10 μm). The silicon dioxide can be silicon dioxide (median diameter of 0.5-1 μm) powder. Spinel black pigments are preformed and are also commercially available.

In the present invention, step (1) is carried out by grinding powders of the above-mentioned oxides as raw materials to reduce the particle diameter and obtain a slurry. The grinding process is wet grinding, and the specific process can comprise the following steps: mixing the powder of the oxides and water into slurry, ball-milling and mixing, and then grinding and crushing to make the particle size median of the oxides to be nano-scale (such as 250-500 nm). More specifically, the oxides are added with water in a ball milling tank according to the content of the oxides for ball milling for 8-10h, then a dispersing agent and water are added in a sand mill for sand milling for 8-10h, finally a binding agent (such as PVA and/or polyethylene glycol 4000) with a proper proportion is added, and then stirring is carried out for 2-4 h. Ball milling pots and sand mills use an inner liner of zirconia ceramic and zirconia milling balls. The selected particle size of the zirconia grinding balls, the proportion of the grinding balls with different particle sizes, the weight ratio of the grinding balls to the powder and the amount of water can be controlled to realize the expected particle size of the oxide.

According to the invention, a method is provided in which the powder is composed of various materials. The material amount of each material can meet the composition requirement of the obtained zirconia ceramics. Preferably, the powder contains 1-4 wt% of niobium oxide and/or tantalum oxide, 6-16 wt% of spinel black pigment, 8-32 wt% of zirconium silicate and 48-84 wt% of zirconium oxide, wherein the zirconium oxide contains 2-4 mol% of yttrium oxide; preferably, the powder contains 2.1-3.6 wt% of niobium oxide and/or tantalum oxide, 8-15 wt% of spinel black pigment, 15-28 wt% of zirconium silicate, 53-74.5 wt% of zirconium oxide, and the zirconium oxide contains 2-4 mol% of yttrium oxide. The powder may also contain impurities that do not affect the performance of the zirconia ceramic of the present invention. The total weight of the respective substances in the powder was 100 wt%.

According to the invention, the dispersing agent can promote the components in the powder to be uniformly mixed. Preferably, in the step (1), the dispersant is at least one selected from hypromellose, sodium carboxymethylcellulose and triethanolamine. In the present invention, the dispersant is commercially available.

According to the invention, the dispersant is preferably added in an amount of 0.005-0.5 wt%, preferably 0.01-0.1 wt%, of the powder.

According to the invention, the binder contributes to the moldability of the powder. Preferably, the binder is selected from polyvinyl alcohol and/or polyethylene glycol. Preferably, the binder is polyvinyl alcohol and polyethylene glycol. More preferably, the molar ratio of the polyvinyl alcohol to the polyethylene glycol is 1: 1-2, preferably 1: 1. Wherein the polyvinyl alcohol has an average molecular weight of 60000-200000. The average molecular weight of polyethylene glycol is 2000-6000. Polyethylene glycol 4000 may be selected as the specific polyethylene glycol. In the present invention, the binder is commercially available.

According to the invention, the binder is preferably added in an amount of 0.5 to 5 wt%, preferably 2 to 5 wt%, of the powder.

According to the invention, the solids content of the slurry is preferably 20 to 60% by weight, preferably 25 to 55% by weight. A better abrasive effect can be achieved.

In the present invention, various drying methods, for example, spray drying, may be employed in the step (2) to form spherical powder having high flowability. The air inlet temperature of spray drying is preferably 220-280 ℃, the air outlet temperature is preferably 100-120 ℃, and the centrifugal rotating speed is 10-20 r/s.

According to the invention, the step (3) can be used for preparing the composite zirconia powder into ceramic. The composite zirconia powder may be formed and then sintered. The molding can adopt dry pressing, isostatic pressing, injection molding, hot-press molding and other molding modes. Preferably dry pressing, a press with 180 and 200 tons of tonnage can be used for forming by using the oil pressure of 8MPa, such as the shape of a rear cover of a mobile phone. The sintering may be air sintering. Preferably, the sintering procedure comprises: raising the temperature from room temperature to 600 ℃ for 400min and preserving heat for 2h, raising the temperature from 600 ℃ to 1150 ℃ for 300min and preserving heat for 2h, raising the temperature from 1150 ℃ to 1300 ℃ for 150min and preserving heat for 2h, raising the temperature from 1300 ℃ to 1350 ℃ and 1450 ℃ for 1-2h, then reducing the temperature to 900 ℃ for 150min, and finally naturally cooling to room temperature.

In the invention, the ceramic obtained by sintering and re-sintering also comprises the steps of flat grinding and polishing, and cutting into final products by using a laser.

In a third aspect of the present invention, there is provided a black zirconia ceramic obtained by the production method of the present invention. The zirconia ceramic has low dielectric constant, low density, high impact resistance, high toughness and easy processability.

The zirconia ceramic comprises the following components in terms of elements: zr, Y, Si, Al, Zn, Co, Ni, Mn, Mg, Fe, Cr, and Nb and/or Ta, and the phase of the zirconia ceramic comprises: tetragonal phase of zirconium oxide or ZrSiO₄And spinel black pigment, the spinel black pigment having a chemical formula of [ Co_eNi_fMn_gZn_hMg_(1-e-f-g-h)][Fe_xCr_yAl_(1-x-y)]₂O₄Wherein e is more than or equal to 0 and less than or equal to 1, f is more than or equal to 0 and less than or equal to 1, g is more than or equal to 0 and less than or equal to 1, h is more than or equal to 0 and less than or equal to 0.5, and e + f + g is more than or equal to 0.5 and less than or equal to 1; x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and x + y is more than 0 and less than or equal to 1; the tetragonal zirconia is a solid solution formed by yttria, niobia and/or tantalum oxide and zirconia.

In the zirconia ceramic, preferably, the zirconia ceramic contains, in terms of elements: the zirconia ceramic comprises, in elemental terms: 45.4-63 wt% Zr, 1.85-4.85 wt% Y, 1.2-4.8 wt% Si, 0-5 wt% Al, 0-3 wt% Zn, 0-5.3 wt% Co, 0-5.3 wt% Ni, 0-5.1 wt% Mn, 0-1.22 wt% Mg, 0-8.3 wt% Fe, 0-8 wt% Cr, 0.7-2.8 wt% Nb and/or Ta; preferably comprising: 48.2-60.5 wt.% Zr, 2-4.5 wt.% Y, 2.2-4.2 wt.% Si, 1.5-5.2 wt.% Al, 0-1.2 wt.% Zn, 0.7-2.3 wt.% Co, 0.7-2.3 wt.% Ni, 0.7-2.3 wt.% Mn, 0-0.46 wt.% Mg, 1.2-2.9 wt.% Fe, 0.17-1.2 wt.% Cr, 1.4-2.4 wt.% Nb and/or Ta.

In the zirconia ceramic, preferably, the phase of the zirconia ceramic contains: 48.9-84.8 wt% of tetragonal zirconia, 7.8-31.7 wt% of ZrSiO4 and 5.9-15.9 wt% of the spinel black pigment; preferably comprising: 54.9-77.7 wt% of tetragonal zirconia, 14.7-27.9 wt% of ZrSiO4 and 7.8-14.9 wt% of spinel black pigment.

Preferably, the dielectric constant of the ceramic is 20 to 29, and the density of the zirconia ceramic is not more than 5.7g/cm³The thinning speed of the zirconia ceramic is more than 40 wires/h, and the average drop weight height of the zirconia ceramic is more than 27 cm.

The fourth aspect of the invention provides the application of the black zirconia ceramic in the preparation of the back shell of a mobile phone.

The present invention will be described in detail below by way of examples. In the following examples of the present invention,

fracture toughness K_ic: indenter indentation method (diamond indenter, force 10kg, pressure test time 15 s).

Hardness Hv: a hardness meter and an indentation method (a diamond indenter, a force of 10kg, a pressure test time of 15 s).

Processability: the dimensional speed under the copper grinding disc, for example, the fixed time is 1 hour, and the thickness difference before and after the copper grinding is tested and recorded as the thinning speed (wire/h).

Drop hammer impact: the sample was placed on a platform using a drop hammer impact tester (manufacturer CKSI, model E602SS), the center of the sample was hammered with a drop hammer weighing 60g, starting from a height of 5cm, and increasing in height of 5cm each time if no crack occurred, until the sample was visually observed to crack, and the height value was recorded.

Dielectric constant: the dielectric constant of the material at 2GHz was measured using a network analyzer.

XRF detection: the element content of the polished sample was measured using an energy dispersive X-ray fluorescence spectrometer EDX-7000. In the following examples, all the elemental composition contents obtained by high-energy XRF detection of the prepared samples are calculated based on the total amount of the samples.

Colorimetric (Lab) test: the L, a, b values of the samples were measured using a color difference meter from Nosu Electron-China-color 1101 and compared with a standard sample of carbon black which was blackened. L is 41-46, a is-0.5 to 0.5, b is-1 to 1, and black is indicated.

Example 1

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.45 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 64.4 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 2

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄12.5% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball mill tank for ball milling for 8h, then adding 0.01 wt% of triethanolamine and water into a sand mill for sand milling for 10h, and finally adding 5 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder and stirring for 0.5h to form slurry for spraying, wherein the solid content is 55 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1380 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 56.5 wt% of Zr, 3.35 wt% of Y, 1.7 wt% of Nb and 1.89 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.45 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 74.8 wt% of tetragonal zirconia, ZrSiO₄11.9 wt%, spinel black pigment 12.1 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 3

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄30.5% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.1 wt% of sodium carboxymethylcellulose and water into a sand mill, sand milling for 10h, and finally adding 2 wt% of binder (PEG 4000 and PVA in a molar ratio of 1: 1) into the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 40 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 52.5 wt% Zr, 3.11 wt% Y, 1.69 wt% Nb and 4.5 wt% Si. Coloring material related elements: 1.22 wt% of Co, 1.21 wt% of Ni, 1.19 wt% of Mn, 1.8 wt% of Fe, 0.43 wt% of Cr and 2.32 wt% of Al.

The phases of the samples included: 56.8 wt% of tetragonal zirconia, ZrSiO₄30.4 wt%, spinel black pigment 12.4 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 4

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 10 wt% spinel black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding hydroxypropyl methylcellulose and water sand mill which account for 0.02 wt% of the powder in a sand mill, and finally adding a binder (PEG 4000 and PVA with a molar ratio of 1: 1) which accounts for 4 wt% of the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 55.9 wt% Zr, 3.33 wt% Y, 1.68 wt% Nb, and 3.4 wt% Si. Coloring material related elements: 0.97 wt% of Co, 0.96 wt% of Ni, 0.95 wt% of Mn, 1.4 wt% of Fe, 0.35 wt% of Cr and 1.85 wt% of Al.

The phases of the samples included: 66.8 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment phase 9.7 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 5

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 15 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding hydroxypropyl methylcellulose and water sand mill which account for 0.02 wt% of the powder in a sand mill, and finally adding a binder (PEG 4000 and PVA with a molar ratio of 1: 1) which accounts for 4 wt% of the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 52.5 wt% Zr, 3.11 wt% Y, 1.7 wt% Nb and 3.4 wt% Si. Coloring material related elements: 1.47 wt% of Co, 1.46 wt% of Ni, 1.44 wt% of Mn, 2.14 wt% of Fe, 0.53 wt% of Cr and 2.78 wt% of Al.

The phases of the samples included: 61.8 wt% of tetragonal zirconia, ZrSiO₄22.4 wt%, spinel black pigment phase 12.3 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 6

Raw materials: 200g of composite powder containing 2 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding hydroxypropyl methylcellulose and water sand mill which account for 0.02 wt% of the powder in a sand mill, and finally adding a binder (PEG 4000 and PVA with a molar ratio of 1: 1) which accounts for 4 wt% of the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.5 wt% of Zr, 3.24 wt% of Y, 1.37 wt% of Nb and 3.4 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.45 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 64.8 wt% of tetragonal zirconia, ZrSiO₄22.3 wt%, spinel black pigment phase 12.4 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 7

Raw materials: 200g of composite powder containing 3 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding hydroxypropyl methylcellulose and water sand mill which account for 0.02 wt% of the powder in a sand mill, and finally adding a binder (PEG 4000 and PVA with a molar ratio of 1: 1) which accounts for 4 wt% of the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 53.9 wt% of Zr, 3.21 wt% of Y, 2.07 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.44 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 65 wt% of tetragonal zirconia, ZrSiO₄22.3 wt%, spinel black pigment phase 12.5 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 8

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.14Cr_0.18Al_0.68]₂O₄22.8% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.2 wt% of Fe, 1.1 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 64.5 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia including yttria and yttriaNiobium and zirconia.

Example 9

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.29Cr_0.03Al_0.68]₂O₄22.8% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 2 wt% of Fe, 0.18 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 64.4 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 10

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/4Ni_1/4Mn_1/4Zn_1/4][Fe_0.25Cr_0.07Al_0.68]₂O₄22.8% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 0.93 wt% of Co, 0.92 wt% of Ni, 0.86 wt% of Mn, 1 wt% of Zn, 1.7 wt% of Fe, 0.43 wt% of Cr and 2.3 wt% of Al.

The phases of the samples included: 64.4 wt% of tetragonal zirconia, ZrSiO₄22.4 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 11

Raw materials: 200g of composite powder, which comprises 25 wt% niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/4Ni_1/4Mn_1/4Mg_1/4][Fe_0.25Cr_0.07Al_0.68]₂O₄22.8% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 0.92 wt% of Co, 0.91 wt% of Ni, 0.85 wt% of Mn, 0.4 wt% of Mg, 1.6 wt% of Fe, 0.42 wt% of Cr and 2.3 wt% of Al.

The phases of the samples included: 64.5 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 12

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅)，12.5 wt% spinel Black pigment Co₁[Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.2 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 3.7 wt% of Co, 1.7 wt% of Fe, 0.43 wt% of Cr and 2.3 wt% of Al.

The phases of the samples included: 64.4 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Example 13

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/2Ni_1/2][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6 wt% of zirconium silicateThe balance was stabilized zirconia powder containing 3 mol% yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 54.3 wt% of Zr, 3.21 wt% of Y, 1.7 wt% of Nb and 3.5 wt% of Si. Coloring material related elements: 1.8 wt% of Co, 1.7 wt% of Ni, 1.7 wt% of Fe, 0.42 wt% of Cr and 2.2 wt% of Al.

The phases of the samples included: 64.4 wt% of tetragonal zirconia, ZrSiO₄22.3 wt%, spinel black pigment 12.3 wt%, and tetragonal zirconia was a solid solution of yttria, niobia, and zirconia.

Comparative example 1

Raw materials: 200g of composite powder containing niobium pentoxide (Nb)₂O₅)2.5 wt%, alumina (Al)₂O₃)25 wt%, the remainder being stabilized zirconia powder containing 3 mol% yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding hydroxypropyl methylcellulose and water sand mill which account for 0.02 wt% of the powder in a sand mill, and finally adding a binder (PEG 4000 and PVA with a molar ratio of 1: 1) which accounts for 4 wt% of the powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1470 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 50.5 wt% of Zr, 2.9 wt% of Y, 1.7 wt% of Nb and 13.2 wt% of Al.

The phases of the samples included: 74.8 wt% of tetragonal zirconia, Al₂O₃24.7 wt%, and tetragonal zirconia is a solid solution of yttria, niobia, and zirconia.

Comparative example 2

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 63.1 wt% Zr, 3.7 wt% Y, 1.7 wt% Nb and 3.4 wt% Si.

The phases of the samples included: 77.1 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, and tetragonal zirconia is a solid solution of yttria, niobia, and zirconia.

Comparative example 3

Raw materials: 200g of composite powder containing 2.5 wt% of niobium pentoxide (Nb)₂O₅) 12.5 wt% spinel Black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄The balance was stabilized zirconia powder containing 3 mol% yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 59.4 wt% of Zr, 3.5 wt% of Y and 1.6 wt% of Nb. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.45 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 87.3 wt% of tetragonal zirconia, 12.2 wt% of spinel black pigment, and a solid solution of yttria, niobia, and zirconia.

Comparative example 4

Raw materials: 200g of composite powder containing 12.5 wt% of spinel black pigment [ Co ]_1/3Ni_1/3Mn_1/3][Fe_0.25Cr_0.07Al_0.68]₂O₄22.6% by weight of zirconium silicate, the remainder being stabilized zirconia powder containing 3 mol% of yttria.

Adding water into the raw materials in a ball milling tank, ball milling for 8h, then adding 0.02 wt% of hydroxypropyl methylcellulose and water into a sand mill, carrying out sand milling for 10h, and finally adding 4 wt% of binder (PEG 4000 and PVA with a molar ratio of 1: 1) of powder, stirring for 0.5h to form slurry for spraying, wherein the solid content is 25 wt%;

feeding the slurry into a spray tower for spray drying (the inlet air temperature is 250 ℃, the outlet air temperature is 110 ℃, and the centrifugal rotating speed is 15 revolutions per second) to form spherical powder with stronger fluidity for dry pressing, and then performing dry pressing (a press with 200 tons of tonnage uses the oil pressure of 8 MPa);

heating the formed powder from room temperature to 600 ℃ for 400min and preserving heat for 2h, heating from 600 ℃ for 300min to 1150 ℃ and preserving heat for 2h, heating from 1150 ℃ for 150min to 1370 ℃ and preserving heat for 2h, then cooling to 900 ℃ for 150min, and finally sintering in the air in the process of naturally cooling to room temperature.

And grinding, polishing and laser cutting the sintered product to obtain a final sample, wherein the size of the final sample is 150 x 75 x 0.6mm, and the size of the final sample is the shape and the size of the mobile phone rear cover.

And (3) carrying out high-energy XRF detection on the prepared sample, wherein the element composition comprises: 56.1 wt% of Zr, 3.21 wt% of Y and 3.5 wt% of Si. Coloring material related elements: 1.24 wt% of Co, 1.23 wt% of Ni, 1.2 wt% of Mn, 1.78 wt% of Fe, 0.45 wt% of Cr and 2.35 wt% of Al.

The phases of the samples included: 64.5 wt% of tetragonal zirconia, ZrSiO₄22.5 wt%, spinel black pigment 12.2 wt%, and tetragonal zirconia was a solid solution of yttria and zirconia.

Test example 1

The samples obtained in examples 1 to 13 and comparative examples 1 to 4 were subjected to hardness, toughness, chroma, dielectric constant, density, processability and falling weight impact tests, and the results are shown in Table 1.

TABLE 1

TABLE 1 (continuation)

As can be seen from Table 1, the zirconia ceramics prepared by the method of the present invention have the characteristics of low dielectric constant, low density, good processability and high strength. Specifically, the dielectric constant is less than 29 and the density is less than 5.7g/cm³The thinning speed is more than 40 threads/h, and the drop weight height is more than 27 cm. Meanwhile, the zirconia ceramics of the invention is black in color by a chromaticity test. The conventional high-toughness zirconia provided in comparative example 1 cannot simultaneously have the above four properties, and the overall properties are inferior to those of the zirconia ceramic of the present invention. In comparative examples 2 to 4, in which spinel black pigment, silica or niobium oxide were absent from the raw materials, the obtained zirconia ceramics could not have the above four properties at the same time.

In order to have a similar low dielectric constant and low density, comparative example 1 employed a conventional manner of adding a large amount of alumina alone, resulting in a great drop in the thinning rate to a point where it is hardly processable.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.