阅读说明：本技术 一种导电性较强的高性能陶瓷材料及其制备方法 (High-performance ceramic material with high conductivity and preparation method thereof ) 是由 钱清廉 于 2021-02-24 设计创作，主要内容包括：本发明公开了一种导电性较强的高性能陶瓷材料及其制备方法,对于原料的预处理使用特殊的多次煅烧方式,第一次高温煅烧提高粉体活性,降低粉体的烧结温度；第二次煅烧部分碳化硅与二氧化硅和氮气反应,转变为氮化硅；第三次煅烧氧化锆与碳反应生成碳化锆；使陶瓷材料了粒大小不一；第三次煅烧后加入锌粉,烧结时锌粉被氧化成四针状的氧化锌,使陶瓷材料获得导电性能；高温煅烧后使用的烧结助剂,在烧结过程中会形成少量的氧化物,在碳化硅晶粒间形成一层薄膜,使生成的四针状氧化锌穿插在薄膜中,碳化硅变成由铝和氧掺杂的复合相沉淀在四针状氧化锌晶粒表面,共同形成交叉的三维导电网络,增强导电性能。(The invention discloses a high-performance ceramic material with stronger conductivity and a preparation method thereof.A special multi-time calcination mode is used for the pretreatment of raw materials, the activity of the powder is improved by the first high-temperature calcination, and the sintering temperature of the powder is reduced; the second time of calcining partial silicon carbide, silicon dioxide and nitrogen react to be converted into silicon nitride; the third time of the reaction of the calcined zirconia and carbon generates zirconium carbide; the grain sizes of the ceramic materials are different; adding zinc powder after the third calcination, and oxidizing the zinc powder into tetrapod-like zinc oxide during sintering to ensure that the ceramic material obtains conductive performance; the sintering aid used after high-temperature calcination can form a small amount of oxides in the sintering process, a layer of thin film is formed among silicon carbide crystal grains, the generated tetrapod-like zinc oxide is inserted in the thin film, and the silicon carbide is changed into a composite phase doped with aluminum and oxygen and is precipitated on the surfaces of the tetrapod-like zinc oxide crystal grains to jointly form a crossed three-dimensional conductive network so as to enhance the conductivity.)

1. The high-performance ceramic material with relatively high conductivity is characterized by comprising the following raw materials in parts by weight: 20-30 parts of zirconium oxide, 80-120 parts of silicon carbide, 8-16 parts of aluminum oxide, 10-25 parts of zinc powder, 2-4 parts of yttrium oxide, 20-40 parts of sintering aid and 30-60 parts of polyvinyl alcohol.

2. The highly conductive high performance ceramic material of claim 1, wherein: the sintering aid is formed by wrapping alumina and yttrium oxide with polyvinyl alcohol.

3. The preparation method of the high-performance ceramic material with stronger conductivity is characterized in that the process flow for preparing the high-performance ceramic material with stronger conductivity is as follows: ball-milling ceramic raw materials, special high-temperature calcination, secondary ball milling, preparing a sintering aid, liquid-phase sintering, and cooling to obtain a finished product.

4. The method for preparing the high-performance ceramic material with stronger electrical conductivity according to claim 3, characterized by comprising the following specific steps:

(1) mixing zirconium oxide and silicon carbide according to a certain proportion to form a mixed material;

(2) adding a material to the mixed material according to the volume ratio of 1: 1, preparing a wet material by using absolute ethyl alcohol, and grinding the wet material in a ceramic ball mill for 1.5-3 hours;

(3) placing the mixed material in a roasting furnace for first high-temperature calcination;

(4) adjusting the temperature, introducing nitrogen, and performing secondary high-temperature calcination;

(5) keeping the temperature unchanged, and introducing pulse current into the mixed material for carrying out third high-temperature calcination, wherein the current is 1kA, and the period is 0.08S;

(6) adding zinc powder after high-temperature calcination, placing the mixed material in a ceramic ball mill, and carrying out secondary ball milling;

(7) soaking alumina and yttria in polyvinyl alcohol of three times volume to prepare a sintering aid;

(8) adding a sintering aid into the mixed material subjected to secondary ball milling, and performing liquid phase sintering, wherein the sintering temperature is kept at 930-1100 ℃;

(9) after sintering, performing gradient temperature quick-drop cooling to obtain a finished product.

5. The method for preparing high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein the method comprises the following steps: in the step (1): the mass ratio of the zirconium oxide to the silicon carbide is 1: 4.

6. the method for preparing a high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein in the step (3): the first high-temperature calcination temperature is 1700-1900 ℃.

7. The method for preparing a high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein in the step (4): the second high-temperature calcination temperature is 2100-2300 ℃.

8. The method for preparing high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein in the step (6): adding zinc powder and the mixed materials in a volume ratio of 1: 8.

9. the method for preparing high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein in the step (7): the mass ratio of the aluminum oxide to the yttrium oxide is 4: 1.

10. the method for preparing high-performance ceramic material with stronger electrical conductivity according to claim 4, wherein in the step (9): and when the temperature is reduced, the temperature reduction speed is 200 ℃/h, the heat preservation is carried out every 1h, and the heat preservation time is 0.5 h.

Technical Field

The invention relates to the field of new materials, in particular to a high-performance ceramic material with stronger electrical conductivity and a preparation method thereof.

Background

The conductive ceramic material is a material with novel functions of ion conduction and electron/hole conduction in a ceramic material, and has wide application prospects in various fields of energy, metallurgy, shift change, electrochemical devices and the like. The conductive ceramic has the characteristics of oxidation resistance, corrosion resistance, radiation resistance, high temperature resistance, long service life and the like, and can be used for electrodes of solid fuel cells, gas sensitive elements, high-temperature heating, solid resistors, redox materials, high-critical-temperature superconducting materials and the like.

The conductivity of the silicon carbide ceramic material is improved, the problem of limited application can be solved, the electric spark machining condition can be met after the conductivity reaches a certain degree, and the later-stage machining forming of the silicon carbide ceramic material can be rapidly and accurately completed by utilizing the electric spark machining. If the ceramic material not only has conductive performance, but also has other excellent performances, the application range of the ceramic material can be widened. Therefore, the research on the high-performance ceramic material with stronger conductivity is very promising. Therefore, it is very necessary to prepare a novel ceramic material with excellent heat insulation performance.

Disclosure of Invention

The present invention is to provide a high-performance ceramic material with high electrical conductivity to solve the above problems in the background art.

In order to solve the above technical problem, a first aspect of the present invention provides the following technical solutions: the high-performance ceramic material with relatively high conductivity is characterized by comprising the following raw materials in parts by weight:

20-30 parts of zirconium oxide, 80-120 parts of silicon carbide, 8-16 parts of aluminum oxide, 10-25 parts of zinc powder, 2-4 parts of yttrium oxide, 20-40 parts of sintering aid and 30-60 parts of polyvinyl alcohol.

Preferably, the sintering aid is formed by wrapping alumina and yttrium oxide with polyvinyl alcohol.

The second aspect of the present invention provides: a preparation method of a high-performance ceramic material with stronger electrical conductivity is characterized by comprising the following steps:

the process flow for preparing the high-performance ceramic material with stronger electrical conductivity comprises the following steps:

ball-milling ceramic raw materials, special high-temperature calcination, secondary ball milling, preparing a sintering aid, liquid-phase sintering, and cooling to obtain a finished product.

Preferably, the method comprises the following specific steps:

(1) mixing zirconium oxide and silicon carbide according to a certain proportion to form a mixed material;

(2) adding a material to the mixed material according to the volume ratio of 1: 1, preparing a wet material by using absolute ethyl alcohol, and grinding the wet material in a ceramic ball mill for 1.5-3 hours;

(3) placing the mixed material in a roasting furnace for first high-temperature calcination;

(4) adjusting the temperature, introducing nitrogen, and performing secondary high-temperature calcination;

(5) keeping the temperature unchanged, and introducing pulse current into the mixed material for carrying out third high-temperature calcination, wherein the current is 1kA, and the period is 0.08S;

(6) adding zinc powder after high-temperature calcination, placing the mixed material in a ceramic ball mill, and carrying out secondary ball milling;

(7) soaking alumina and yttria in polyvinyl alcohol of three times volume to prepare a sintering aid;

(8) adding a sintering aid into the mixed material subjected to secondary ball milling, and performing liquid phase sintering, wherein the sintering temperature is kept at 930-1100 ℃;

(9) after sintering, performing gradient temperature quick-drop cooling to obtain a finished product.

Preferably, in the step (1): the mass ratio of the zirconium oxide to the silicon carbide is 1: 4.

preferably, in the step (3): the first high-temperature calcination temperature is 1700-1900 ℃.

Preferably, in the step (4): the second high-temperature calcination temperature is 2100-2300 ℃.

Preferably, in the step (6): adding zinc powder and the mixed materials in a volume ratio of 1: 8.

preferably, in the step (7): the mass ratio of the aluminum oxide to the yttrium oxide is 4: 1.

preferably, in the step (9): and when the temperature is reduced, the temperature reduction speed is 200 ℃/h, the heat preservation is carried out every 1h, and the heat preservation time is 0.5 h.

Compared with the prior art, the invention has the following beneficial effects:

a special multi-time calcination mode is used for the pretreatment of the raw materials; firstly, grinding raw materials of silicon carbide, silicon dioxide and zirconia by ball milling, and then carrying out first high-temperature calcination, so that the activity of the powder is improved, and the sintering temperature of the powder is reduced; then raising the temperature, carrying out secondary calcination in a nitrogen atmosphere, and reacting part of silicon carbide with silicon dioxide and nitrogen to convert the silicon carbide into silicon nitride and generate carbon; and finally, pulse current is directly introduced among the particles to carry out third calcination, zirconium oxide reacts with carbon to generate zirconium carbide, high-resistance components of the ceramic material after the third calcination are silicon carbide, zirconium oxide, silicon nitride and zirconium carbide with different particle sizes, zinc powder is added after the third calcination, secondary ball milling is carried out, liquid phase sintering is carried out after the ball milling, the zinc powder is oxidized into tetrapod-like zinc oxide during sintering and is inserted into the ceramic material with different particle sizes, and after sintering, the tetrapod-like zinc oxide is uniformly distributed in the ceramic material to form an electroosmosis flow network, so that the ceramic material not only obtains conductivity, but also obtains high performances of oxidation resistance and cold and heat impact resistance.

After high-temperature calcination, polyvinyl alcohol is used for wrapping alumina and yttrium oxide as sintering aids to carry out granulation and liquid phase sintering, the polyvinyl alcohol is used as a binder during granulation, the alumina and yttrium oxide are directly released during molding, and the molding and sintering are carried out, so that the process flow is reduced, and the ceramic material obtains the alternating current conductivity; a small amount of oxide can be formed in the liquid phase sintering process, a layer of thin film is formed among the rest silicon carbide crystal grains, the sintering time is prolonged, the content of oxygen and aluminum in the material is reduced, the thickness of the thin film is reduced, the silicon carbide crystal grains are dissolved and then precipitated on the surfaces of the tetrapod-shaped zinc oxide crystal grains along with the generation of the tetrapod-shaped zinc oxide and are inserted in the thin film, the silicon carbide crystal grains are subjected to long-time sintering in the liquid phase, the silicon carbide is changed into a composite phase doped with aluminum and oxygen, the silicon carbide has electric conduction capability, a crossed three-dimensional electric conduction network is formed together with the zinc oxide, the electric conduction performance is enhanced, and the electric.

After sintering, gradient temperature rapid-drop cooling is carried out, and as the ceramic material has cold and heat resistance, the ceramic material cannot be affected.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The high-performance ceramic material with relatively high conductivity is characterized by comprising the following raw materials in parts by weight:

20-30 parts of zirconium oxide, 80-120 parts of silicon carbide, 8-16 parts of aluminum oxide, 10-25 parts of zinc powder, 2-4 parts of yttrium oxide, 20-40 parts of sintering aid and 30-60 parts of polyvinyl alcohol.

Preferably, the sintering aid is formed by wrapping alumina and yttrium oxide with polyvinyl alcohol.

The second aspect of the present invention provides: a preparation method of a high-performance ceramic material with stronger electrical conductivity is characterized by comprising the following steps:

the process flow for preparing the high-performance ceramic material with stronger electrical conductivity comprises the following steps:

ball-milling ceramic raw materials, special high-temperature calcination, secondary ball milling, preparing a sintering aid, liquid-phase sintering, and cooling to obtain a finished product.

Preferably, the method comprises the following specific steps:

(1) mixing zirconium oxide and silicon carbide according to a certain proportion to form a mixed material;

(2) adding a material to the mixed material according to the volume ratio of 1: 1, preparing a wet material by using absolute ethyl alcohol, and grinding the wet material in a ceramic ball mill for 1.5-3 hours;

(3) placing the mixed material in a roasting furnace for first high-temperature calcination;

(4) adjusting the temperature, introducing nitrogen, and performing secondary high-temperature calcination;

(5) keeping the temperature unchanged, and introducing pulse current into the mixed material for carrying out third high-temperature calcination, wherein the current is 1kA, and the period is 0.08S;

(6) adding zinc powder after high-temperature calcination, placing the mixed material in a ceramic ball mill, and carrying out secondary ball milling;

(7) soaking alumina and yttria in polyvinyl alcohol of three times volume to prepare a sintering aid;

(8) adding a sintering aid into the mixed material subjected to secondary ball milling, and performing liquid phase sintering, wherein the sintering temperature is kept at 930-1100 ℃;

(9) after sintering, performing gradient temperature quick-drop cooling to obtain a finished product.

Preferably, in the step (1): the mass ratio of the zirconium oxide to the silicon carbide is 1: 4.

preferably, in the step (3): the first high-temperature calcination temperature is 1700-1900 ℃.

Preferably, in the step (4): the second high-temperature calcination temperature is 2100-2300 ℃.

Preferably, in the step (6): adding zinc powder and the mixed materials in a volume ratio of 1: 8.

preferably, in the step (7): the mass ratio of the aluminum oxide to the yttrium oxide is 4: 1.

preferably, in the step (9): and when the temperature is reduced, the temperature reduction speed is 200 ℃/h, the heat preservation is carried out every 1h, and the heat preservation time is 0.5 h.

Example 1: the first high-performance ceramic material with stronger conductivity:

a high-performance ceramic material with strong electrical conductivity comprises the following components in parts by weight:

20 parts of zirconium oxide, 80 parts of silicon carbide, 8 parts of aluminum oxide, 10 parts of zinc powder, 2 parts of yttrium oxide, 20 parts of sintering aid and 30 parts of polyvinyl alcohol.

The preparation method of the ceramic material comprises the following steps:

(1) mixing 20 parts by weight of zirconia and 80 parts by weight of silicon carbide to form a mixed material;

(2) adding a material to the mixed material according to the volume ratio of 1: 1, preparing a wet material by using absolute ethyl alcohol, and grinding the wet material in a ceramic ball mill for 1.5 hours;

(3) placing the mixed material in a roasting furnace for primary high-temperature calcination, wherein the calcination temperature is 1700 ℃;

(4) regulating the temperature to 2100 ℃, introducing nitrogen, and performing secondary high-temperature calcination;

(5) keeping the temperature unchanged, and introducing pulse current into the mixed material for carrying out third high-temperature calcination, wherein the current is 1kA, and the period is 0.08S;

(6) after high-temperature calcination, adding 10 parts by weight of zinc powder, placing the mixture in a ceramic ball mill, and carrying out secondary ball milling;

(7) soaking 8 parts of alumina and 2 parts of yttrium oxide in three times of volume of polyvinyl alcohol to prepare a sintering aid;

(8) adding a sintering aid into the mixed material subjected to secondary ball milling, and performing liquid phase sintering, wherein the sintering temperature is kept at 1000 ℃;

(9) after sintering, performing gradient temperature rapid-reduction type cooling at the cooling speed of 200 ℃/h, performing heat preservation every 1h for 0.5h, and thus obtaining a finished product.

Example 2: the first high-performance ceramic material with stronger conductivity:

a high-performance ceramic material with strong electrical conductivity comprises the following components in parts by weight:

30 parts of zirconia, 120 parts of silicon carbide, 16 parts of alumina, 25 parts of zinc powder, 4 parts of yttrium oxide, 40 parts of sintering aid and 60 parts of polyvinyl alcohol.

The preparation method of the ceramic material comprises the following steps:

(1) mixing 30 parts by weight of zirconium oxide and 120 parts by weight of silicon carbide to form a mixed material;

(2) adding a material to the mixed material according to the volume ratio of 1: 1, preparing a wet material by using absolute ethyl alcohol, and grinding the wet material in a ceramic ball mill for 3 hours;

(3) placing the mixed material in a roasting furnace for primary high-temperature calcination, wherein the calcination temperature is 1900 ℃;

(4) adjusting the temperature to 2300 ℃, introducing nitrogen, and performing secondary high-temperature calcination;

(5) keeping the temperature unchanged, and introducing pulse current into the mixed material for carrying out third high-temperature calcination, wherein the current is 1kA, and the period is 0.08S;

(6) after high-temperature calcination, adding 25 parts by weight of zinc powder, placing the mixture in a ceramic ball mill, and carrying out secondary ball milling;

(7) soaking 16 parts of alumina and 4 parts of yttrium oxide in three times of volume of polyvinyl alcohol to prepare a sintering aid;

(8) adding a sintering aid into the mixed material subjected to secondary ball milling, and performing liquid phase sintering, wherein the sintering temperature is kept at 1100 ℃;

(9) after sintering, performing gradient temperature rapid-reduction type cooling at the cooling speed of 200 ℃/h, performing heat preservation every 1h for 0.5h, and thus obtaining a finished product.

Comparative example 1

The formulation of comparative example 1 was the same as example 1. The preparation method of the high-performance ceramic material with stronger conductivity is different from the preparation method of the embodiment 1 only in that the preparation processes of the steps (3), (4) and (5) are not carried out, and the step (6) is modified into the following steps: and (3) calcining the mixed material obtained in the step (2) at a high temperature of 1900 ℃, and adding 10 parts by weight of zinc powder to perform secondary ball milling after calcination. The rest of the preparation steps are the same as example 1.

Comparative example 2

Comparative example 2 was formulated as in example 1. The preparation method of the high-performance ceramic material with strong electrical conductivity is different from that of the ceramic material in the embodiment 1 only in that the preparation in the step (7) is not carried out, and the polyvinyl alcohol, the wrapped alumina and the yttrium oxide are added in the step (8) in sequence. The rest of the preparation steps are the same as example 1.

Comparative example 3

The formulation of comparative example 3 was the same as example 1. The preparation method of the high-performance ceramic material with stronger conductivity is different from the embodiment 1 only in the step (9), and the step (9) is modified as follows: and naturally cooling to room temperature after sintering to obtain a finished product. The rest of the preparation steps are the same as example 1.

Test example 1

1. Test method

Example 1 is a control test with respect to comparative examples 1, 2 and 3, and the ceramic material is subjected to resistivity measurements for comparison.

2. Test results

Example 1 is resistivity-compared to comparative examples 1, 2, 3.

TABLE 1 resistivity of the ceramic materials

	Resistivity (omega cm)
		Example 1	36.95
Comparative example 1	59.37
		Comparative example 2	44.21
Comparative example 3	40.99

Compared with the resistivity of the comparative examples 1, 2 and 3, the resistivity of the ceramic material prepared in the example 1 is obviously lower, while the resistivity of the comparative examples 1 and 2 is higher, the lower the resistivity is, the stronger the conductivity is, which shows that the ceramic material prepared in the example 1 has stronger conductivity, and the fact that the high-performance ceramic material with stronger conductivity prepared in the invention has the advantages of conductivity and excellent conductivity is predicted.

Test example 2

1. Test method

Example 1 and comparative example 1 are comparative tests in which a ceramic material is heated in air to 1500 ℃, subjected to 10 rapid cooling and heating, observed for surface change of the ceramic, and subjected to a cold-hot impact resistance test for comparison.

2. Test results

Comparison of example 1 with comparative example 2 against Cold thermal shock

TABLE 2 ceramic surface variation

	5 times of rapid cooling and heating	10 times of rapid cooling and heating
			Example 1	Smooth surface of ceramic	Smooth surface of ceramic
Comparative example 2	Fine cracks appear on the surface of the ceramic	Obvious cracks appear on the surface of the ceramic

Compared with the comparative example 2, the cold and heat impact resistance of the example 1 is obviously found that no crack appears on the surface of the example 1 after 10 times of rapid cooling and heating, which shows that the special multi-time calcination mode used in the example 1 can improve the performance of the ceramic material and enhance the cold and heat impact resistance of the ceramic material, and indicates that the high-performance ceramic material with stronger conductivity prepared by the invention has excellent conductivity and stronger cold and heat impact resistance.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.