阅读说明：本技术 一种陶瓷及其制备方法 (Ceramic and preparation method thereof ) 是由 宋涛 张大军 于宏林 崔凯 王浩然 张永翠 张栋 段文婷 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种陶瓷以及其制备方法,所述陶瓷由以下原料制备而成：氧化铝粉、钛白粉、含金属元素的烧结助剂；所述氧化铝粉包括第一氧化铝粉、第二氧化铝粉,所述第一氧化铝粉的平均粒径大于第二氧化铝粉的平均粒径；所述陶瓷存有若干间隔分布的裂痕,所述裂痕所述裂痕的长度1.5～15um；所述陶瓷吸水率为0.2～2％；热膨胀系数为-0.5～1.5×10～(-6)/℃；抗热震性为温度在650～25℃急冷循环50次不裂。通过所述陶瓷原料包括第一氧化铝粉、第二氧化铝粉、钛白粉,解决了日用陶瓷领域采用锂质耐热瓷导致的原材料紧张问题；同时解决了吸水较大问题,提高了日用陶瓷烧饭的质量、安全性以及使用寿命。(The invention discloses a ceramic and a preparation method thereof, wherein the ceramic is prepared from the following raw materials: alumina powder, titanium dioxide and a sintering aid containing metal elements; the alumina powder comprises a first alumina powder and a second alumina powder, and the average particle size of the first alumina powder is larger than that of the second alumina powder; the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 1.5-15 um; the water absorption rate of the ceramic is 0.2-2%; a coefficient of thermal expansion of-0.5 to 1.5X 10 ‑6 /° c; the thermal shock resistance is that the crack is not generated after 50 times of quenching circulation at the temperature of 650-25 ℃. The problem of raw material shortage caused by adopting lithium heat-resistant porcelain in the field of daily ceramics is solved by the ceramic raw materials comprising the first alumina powder, the second alumina powder and the titanium dioxide; simultaneously solves the problem of large water absorption, improves the quality and the safety of the daily ceramic cooked rice and prolongs the service life of the daily ceramic cooked rice.)

1. The ceramic is characterized by being prepared from the following raw materials: alumina powder, titanium dioxide and a sintering aid containing metal elements;

the alumina powder comprises a first alumina powder and a second alumina powder, and the average particle size of the first alumina powder is larger than that of the second alumina powder;

the ceramic has a plurality of cracks distributed at intervals, and the length of each crack is 1.5-15 um.

2. The ceramic of claim 1, wherein the ceramic comprises 70 to 95% aluminum titanate particles;

the water absorption rate is 0.2-3%; and/or a coefficient of thermal expansion of-0.5 to 1.5 x 10^-6/° c; and/or the thermal shock resistance is that the crack is not generated after 50 times of quenching circulation at the temperature of 650-25 ℃.

3. The ceramic of claim 1, wherein the raw material further comprises a reinforcing agent comprising mullite powder and/or fused silica powder; the mullite powder accounts for 0-15% of the total solid raw material in addition;

the fused quartz accounts for 0-2% of the total mass of the solid raw materials.

4. The ceramic according to claim 1, wherein the first alumina powder particle size D50 is 40-55% of the total solid raw material addition mass in a 2-5 μm part; the part with the second alumina granularity D50 being less than or equal to 0.5 mu m accounts for 0-3% of the total mass of the solid raw materials;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 30-50% of the addition mass of the total solid raw materials.

5. The ceramic of claim 1, wherein the metal element-containing sintering aid comprises talc;

the ratio of the particle size of the talc to the particle size of the alumina powder is (3:10) - (7: 10);

and/or

The sintering aid containing the metal elements comprises at least one of magnesium oxide, magnesium hydroxide and iron oxide, and the particle size ratio of the magnesium oxide, the magnesium hydroxide and the iron oxide to the alumina powder is (2:10) - (5: 10).

6. A method for preparing ceramics is characterized by comprising the following steps:

mixing and grinding first alumina powder, second alumina powder, titanium dioxide, a sintering aid containing metal elements and water to prepare ceramic slurry, wherein the average particle size of the first alumina powder is larger than that of the second alumina powder;

and preparing the ceramic slurry into a ceramic blank, and sintering the ceramic blank to obtain the ceramic material.

7. The method of claim 6, wherein the sintering aid containing a metal element comprises one or more of magnesium hydroxide, magnesium oxide, talc, iron oxide; the sintering temperature of the ceramic body is 1370-1500 ℃, and the cooling rate between 900-1350 ℃ is 2-5 ℃/min in the heating process;

or

The ceramic slurry further comprises a reinforcing agent; the sintering aid containing the metal elements comprises one or more of magnesium hydroxide, magnesium oxide, talc, iron oxide, zirconium oxide and zirconium silicate; the sintering temperature of the ceramic body is 1350-1520 ℃, and in the cooling process, the cooling rate between 1520 ℃ and 1100 ℃ is more than or equal to 3 ℃/min.

8. The method for preparing ceramic according to claim 7, wherein the ceramic slurry is prepared into a ceramic body before the ceramic slurry is prepared into the ceramic body, and the ceramic slurry is prepared secondarily by the following steps:

carrying out heat treatment on the ceramic slurry to prepare first ceramic powder;

and mixing and adding zirconium oxide and/or zirconium silicate, the first ceramic powder, the reinforcing agent and water into a grinding device for grinding to finish secondary preparation of the ceramic slurry.

9. The method for preparing ceramic according to claim 8, wherein the reinforcing agent comprises mullite powder and/or fused silica powder;

the mullite powder comprises a first mullite powder and a second mullite powder, wherein the first mullite powder accounts for 28-32% of the total mullite powder, and the second mullite powder accounts for 68-72% of the total mullite powder;

the grain size ratio of the first mullite powder to the first ceramic powder is (5:1) - (10:1), and the grain size ratio of the second mullite powder to the first ceramic powder is (30:1) - (68: 1);

and/or

The fused quartz powder comprises a first fused quartz powder and a second fused quartz powder, wherein the fused quartz powder accounts for 28-32% of the total fused quartz powder, and the second fused quartz powder accounts for 68-72% of the total fused quartz powder;

the particle size ratio of the first fused quartz powder to the first ceramic powder is (5:1) - (10:1), and the particle size ratio of the second fused quartz powder to the first ceramic powder is (30:1) - (68: 1).

10. The method for preparing ceramic according to claim 8, wherein the heat treatment of the ceramic slurry comprises a first heat treatment temperature and a second heat treatment temperature, wherein the first heat treatment temperature is 950-1050 ℃, the heat treatment time is 2-5 h, and the temperature rise rate of 950-1050 ℃ is 2-3 ℃/min;

the second heat treatment temperature is 1350-1550 ℃, and the heat treatment time is 2.5-3.5 h.

Technical Field

The invention relates to the field of ceramics, in particular to the field of domestic ceramics.

Background

The high thermal shock heat-resistant domestic ceramic is widely used for ceramic stewing pots, electric heating kettle ceramic heating plates, ceramic baking trays, ceramic electric cookers, oven heating ceramic panels and the like; but the high thermal shock heat-resistant domestic ceramic in the market is lithium heat-resistant ceramic; the high thermal shock property is realized by mainly utilizing the characteristic of low thermal expansion coefficient of the ceramic material. At present, the lithium heat-resistant porcelain is mostly prepared by taking spodumene or petalite as a main raw material and clay as an auxiliary raw material through the processes of proportioning, pulping, filter pressing, ageing, molding, drying, glazing, firing and the like.

The conventional lithium heat-resistant porcelain has the following problems: firstly, the raw material resources are limited, the spodumene or petalite mineral resources which can be used for producing the lithic heat-resistant porcelain have limitation, and the shortage of the spodumene or petalite mineral resources is aggravated by the requirement of the lithium battery industry; in the aspect of preparation process, rolling, grouting and other forming methods are generally adopted, wet blank drying processes exist, and preparation efficiency is relatively low. Limited by the characteristics of the forming process, the problems that the bottom of a rolling roller is easy to wear, the thickness of the bottom of a ceramic appliance is not uniform, the size precision of the final ceramic product is low due to the drying deformation of a wet blank and the like exist; thirdly, the water absorption rate is higher by 3-12%, so that the problems of tainting of odor of the stewing pot and the electric cooker and incapability of long-term water storage of the heating plate of the electric kettle (heating cracking of the ceramic after water absorption due to long-term water storage) are easily caused.

Disclosure of Invention

The invention aims to solve the problem of raw material shortage caused by adopting lithium heat-resistant porcelain in the field of daily ceramics; simultaneously, the problem of large water absorption is solved, and the quality, the safety and the service life of the daily ceramic cooked rice are improved; the ceramic is prepared from the following raw materials: alumina powder, titanium dioxide and a sintering aid containing metal elements, wherein the alumina powder comprises a first alumina powder,The average particle size of the first alumina powder is larger than that of the second alumina powder, a plurality of cracks distributed at intervals exist in the ceramic, and the length of each crack is 1.5-15 um; the water absorption rate of the ceramic is 0.2-2%; a coefficient of thermal expansion of-0.5 to 1.5X 10^-6/° c; the thermal shock resistance is that the crack is not generated after 50 times of quenching circulation at the temperature of 650-25 ℃.

In order to achieve the purpose, the technical scheme of the invention is as follows:

according to one aspect of the invention, the ceramic is prepared from the following raw materials: alumina powder, titanium dioxide and a sintering aid containing metal elements; the alumina powder comprises a first alumina powder and a second alumina powder, and the average particle size of the first alumina powder is larger than that of the second alumina powder; the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 1.5-15 um; the cracks are very small micro cracks, and the characterization method of the micro cracks adopts electron microscope detection, and is preferably observed from crystal-penetrating cracks.

Compared with the prior art, the ceramic has the beneficial effects that the ceramic is prepared from the following raw materials: the aluminum titanate ceramic is realized, and the problem of raw material shortage caused by the fact that the ceramic is made of lithium heat-resistant ceramic is solved; the ceramic raw material also comprises a sintering aid containing metal elements, so that the thermal expansion coefficient range of the ceramic can be adjusted and controlled, and the water absorption of the ceramic can be reduced; grading the main raw materials by the mean particle size of the first alumina powder being larger than that of the second alumina powder, so that the particle size of the aluminum titanate ceramic is favorably 3-5 um, the aluminum titanate ceramic has high thermal shock resistance, and the service life of the ceramic in daily use is favorably prolonged; cracks distributed at intervals exist in the ceramic, so that the thermal expansion property can be low, namely when the temperature of the ceramic is changed, the cracks are expanded and filled by ceramic internal particles along with the rise of the temperature, and the external size of the ceramic cannot be obviously increased; meanwhile, the length of the microcrack is 1.5-15 um, so that the microcrack can change along with the temperature for many times, the phenomena of crack extension and enlargement or ceramic cracking caused by the mutual combination of cracks and the like can not occur, and the thermal shock resistance of the ceramic can be improved.

Further, the ceramic comprises 70-95% of aluminum titanate particles; the water absorption rate of the ceramic is 0.2-3%; and/or a coefficient of thermal expansion of-0.5 to 1.5 x 10 < -6 >/DEG C; and/or the thermal shock resistance is that the crack is not generated after 50 times of quenching circulation at the temperature of 650-25 ℃.

The technical scheme adopted in the previous step has the beneficial effects that the ceramic comprises 70-95% of aluminum titanate particles, so that the problem of raw material tension caused by the fact that the ceramic adopts a lithium raw material is solved, and the thermal expansion coefficient of the ceramic is favorably reduced; the water absorption rate of the ceramic is 0.2-2%, so that the phenomenon that the ceramic has odor in the using process is avoided, and the problem that the ceramic is heated and cracked after water is absorbed when water is stored in the ceramic for a long time is solved; the ceramic does not crack after being subjected to quenching circulation for 50 times at 650-25 ℃ through thermal shock resistance, so that the problem of cracking or slag falling can be avoided when the ceramic is frequently heated and cooled in daily use, and the service life of the ceramic is prolonged; the traditional aluminum titanate is frequently heated and cooled within the service temperature range of the domestic ceramics, and the cracking or slag falling phenomenon can occur, so that the traditional aluminum titanate can not be normally used for a long time.

Further, the raw materials also comprise a reinforcing agent, and the reinforcing agent comprises mullite powder and/or fused quartz powder; the mullite powder accounts for 0-15% of the total solid raw material in addition; the fused quartz accounts for 0-2% of the total mass of the solid raw materials.

The technical scheme has the beneficial effects that the ceramic comprises mullite powder and fused quartz, so that a framework is formed in the ceramic, the thermal shock resistance of the ceramic is favorably improved, and the service life of the ceramic is prolonged.

Further, the part with the particle size D50 of the first alumina powder being 2-5 mu m accounts for 40-55% of the added mass of the total solid raw materials; the part with the second alumina granularity D50 being less than or equal to 0.5 mu m accounts for 0-3% of the total mass of the solid raw materials;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 30-50% of the addition mass of the total solid raw materials.

The technical scheme adopted in the previous step has the beneficial effects that the particle size distribution of the aluminum oxide powder and the particle size distribution of the titanium dioxide are beneficial to realizing that the particle size of the aluminum titanate ceramic is 3-5 um and the particle size of the aluminum titanate ceramic is 3-5 um, so that the aluminum titanate ceramic has high thermal shock property; meanwhile, the micro-cracks in the ceramic can be changed along with the temperature for many times, the phenomena of crack extension and enlargement, ceramic cracking caused by mutual combination of cracks and the like can not occur, and the thermal shock property of the ceramic can be improved; therefore, thermal shock resistance is realized, the ceramic does not crack after being subjected to quenching circulation for 50 times at 650-25 ℃, the problem of cracking or slag falling is avoided when the ceramic is frequently heated and cooled in daily use, and the service life of the ceramic is prolonged.

Further, the sintering aid containing the metal element comprises talc; the ratio of the particle size of the talc to the particle size of the alumina powder is (3:10) - (7: 10); and/or the sintering aid containing the metal elements comprises at least one of magnesium oxide, magnesium hydroxide and iron oxide, and the particle size ratio of the magnesium oxide, the magnesium hydroxide and the iron oxide to the alumina powder is (2:10) - (5: 10).

The technical scheme adopted in the previous step has the beneficial effects that the raw materials comprise the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide, and the crystal grains of the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide are favorable for reducing the water absorption of the ceramic; meanwhile, the ratio of the particle size of the talc to the particle size of the alumina powder is (3:10) - (7: 10); the particle size ratio of the magnesium oxide, the magnesium hydroxide and the iron oxide to the alumina powder is (2:10) - (5:10), so that gaps among ceramic particles are obviously reduced, the water absorption of the ceramic is further reduced, and the water absorption of the ceramic is finally realized to be 0.2-2%; the thermal shock daily ceramic has no odor tainting in the using process, and the problem that the ceramic is heated and cracked after water is stored for a long time due to long-term water storage of the ceramic is avoided.

According to another aspect of the present invention, there is provided a method for preparing a ceramic, comprising the steps of: mixing and grinding first alumina powder, second alumina powder, titanium dioxide, a sintering aid containing metal elements and water to prepare ceramic slurry, wherein the average particle size of the first alumina powder is larger than that of the second alumina powder; and preparing the ceramic slurry into a ceramic blank, and sintering the ceramic blank to obtain the ceramic material.

Mixing and grinding the first alumina powder, the second alumina powder, the titanium dioxide and the sintering aid containing the metal element, which are weighed according to the formula proportion, with water in grinding equipment to prepare ceramic slurry;

the part of the alumina powder with the granularity D50 of 2-5 mu m accounts for 40-55% of the total solid addition mass; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 0-3% of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 30-50% of the total solid addition mass;

filtering the ceramic slurry by a 100-mesh screen, granulating by adopting spray drying equipment to prepare ceramic powder, and screening the ceramic powder with 60-250 meshes to prepare a ceramic blank; drying and sintering the ceramic blank to obtain ceramic; sieving the granulated ceramic powder to obtain 60-250-mesh intermediate powder, and performing dry pressing/semi-dry pressing/wet bag isostatic pressing/dry bag isostatic pressing on the intermediate powder, and then trimming to obtain a ceramic blank; or filtering the ceramic slurry through a 100-mesh screen and then performing grouting forming to obtain a ceramic blank; preferably, performing ball milling on the raw materials in ball milling equipment for 4-24 hours to prepare ceramic slurry; the granularity D50 of the prepared ceramic slurry is more than or equal to 3.5 mu m, and then the ceramic slurry with 80-120 meshes is obtained by sieving and screening.

Compared with the prior art, the invention has the beneficial effects that common commercial materials of alumina powder and titanium dioxide are added in the ceramic slurry preparation, so that the aluminum titanate is included in the ceramic, and the problem of raw material shortage caused by the adoption of lithium heat-resistant porcelain in the ceramic is solved; the sintering aid containing the metal element is added into the prepared ceramic slurry, so that the thermal expansion coefficient range of the ceramic is favorably adjusted and controlled, and the water absorption of the ceramic is favorably reduced; the water absorption rate of the ceramic is 0.2-2%; the thermal shock daily ceramic has no odor tainting in the using process, and the problem that the ceramic is heated and cracked after water is absorbed due to long-term water storage of the ceramic is avoided;

the average particle size of the added first alumina powder is larger than that of the second alumina powder, the added material particle size grading is realized, the particle size of aluminum titanate ceramic is favorably realized at 3-5 um, the particle size of the aluminum titanate ceramic is at 3-5 um, and the aluminum titanate ceramic has high thermal shock resistance, so that the thermal shock resistance is realized, the ceramic does not crack at 650-25 ℃ in a quenching circulation for 50 times, the problem of cracking or slag falling can be avoided when the ceramic is frequently heated and cooled in daily use, and the service life of the ceramic is prolonged.

Further, the sintering aid containing the metal element comprises one or more of magnesium hydroxide, magnesium oxide, talc and iron oxide; the sintering temperature of the ceramic body is 1370-1500 ℃, and the cooling rate between 900-1350 ℃ is 2-5 ℃/min in the heating process; preferably, the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide respectively account for 1.3-12%, 1-9%, 2-15% and 0-2% of the total solid addition mass;

or

The ceramic slurry further comprises a reinforcing agent; the sintering aid containing the metal elements comprises one or more of magnesium hydroxide, magnesium oxide, talc, iron oxide, zirconium oxide and zirconium silicate; the sintering temperature of the ceramic body is 1350-1520 ℃, and in the cooling process, the cooling rate between 1520 ℃ and 1100 ℃ is more than or equal to 3 ℃/min; preferably, the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide respectively account for 1.3-12%, 1-9%, 2-15% and 0-2% of the total solid addition mass; in the preparation process of the ceramic slurry, the reinforcing agent comprises mullite powder and/or fused quartz; the ratio of the particle size of the mullite powder to the particle size of the fused quartz powder to the particle size of the alumina powder is (10:1) - (49: 1).

The technical scheme has the beneficial effects that the sintering temperature and the heating rate are beneficial to the aluminum titanate particles with the sizes of 3-5 um, uniform interval distribution of microcracks in the ceramic is realized, the microcrack length is 1.5-15 um, the size and the size are moderate, the thermal shock property is finally improved, and the thermal expansion coefficient is-0.5-1.5 multiplied by 10^-6/DEG C; meanwhile, the sintering aid containing the metal elements comprises materials and the proportion of the materials is favorable for realizing low ceramic absorptivity.

Further, the ceramic slurry secondary preparation is also included before the ceramic slurry is made into a ceramic body, and the ceramic slurry secondary preparation includes: carrying out heat treatment on the ceramic slurry to prepare first ceramic powder; mixing zirconium oxide and/or zirconium silicate with the first ceramic powder, a reinforcing agent and water, adding the mixture into a grinding device, and grinding to finish secondary preparation of ceramic slurry;

preferably, drying, crushing or spray drying the ceramic slurry to prepare primary ceramic powder; screening the primary ceramic powder to obtain a material with the grain size smaller than 100 meshes, carrying out heat treatment, and then grinding and screening the material with the grain size smaller than 100 meshes again to obtain first ceramic powder;

mixing zirconium oxide and/or zirconium silicate with the first ceramic powder, a reinforcing agent and water, adding the mixture into a grinding device, carrying out ball milling, wherein the mass ratio of solid materials to water is 0-60%, preparing ceramic slurry with the granularity D50 of 2.5-4 mu m after 4-24 h, adding PVA (polyvinyl alcohol) serving as a binder, and finishing the secondary preparation of the ceramic slurry, wherein the addition amount of the PVA is 0.3-1.2% of the mass of the solid in the secondary preparation process.

The technical scheme adopted by the previous step has the beneficial effects that the ceramic slurry is prepared for the second time before the ceramic blank is prepared by the ceramic slurry, and the secondary preparation process of the ceramic slurry comprises heat treatment;

the uniform mixing of the main raw materials of alumina powder and titanium dioxide is realized, aluminum titanate particles with uniform particle size are obtained after heat treatment, the uniform aluminum titanate particles are mixed and ground with the reinforcing agent and water to finish the secondary preparation of the ceramic slurry, the uniform mixing of the aluminum titanate and the reinforcing agent is realized, grading can be carried out according to the particle size, the reinforcing agent framework is favorably distributed around the aluminum titanate, the limitation and fixation of microcracks in the aluminum titanate can be effectively realized, the extension and expansion of the microcracks are avoided when the microcracks stretch and shrink along with the temperature change, and the thermal shock performance of the ceramic is improved;

after the ceramic slurry is prepared for the second time, the granularity of the ceramic slurry is D50 and is 2.5-4 mu m, PVA is added to serve as a binder, the ceramic blank particles are uniform, the ceramic blank is high in strength, pores generated during sintering and binder removal are small, the ceramic water absorption rate is finally obtained, internal microcracks can be uniformly distributed at intervals, and thermal shock resistance is improved.

Further, the reinforcing agent comprises mullite powder and/or fused quartz powder; the mullite powder comprises a first mullite powder and a second mullite powder, wherein the first mullite powder accounts for 28-32% of the total mullite powder, and the second mullite powder accounts for 68-72% of the total mullite powder; the grain size ratio of the first mullite powder to the first ceramic powder is (5:1) - (10:1), and the grain size ratio of the second mullite powder to the first ceramic powder is (30:1) - (68: 1); and/or the fused quartz powder comprises a first fused quartz powder and a second fused quartz powder, wherein the fused quartz powder accounts for 28-32% of the total added amount of the fused quartz powder, and the second fused quartz powder accounts for 68-72% of the total added amount of the fused quartz powder; the particle size ratio of the first fused quartz powder to the first ceramic powder is (5:1) - (10:1), and the particle size ratio of the second fused quartz powder to the first ceramic powder is (30:1) - (68: 1).

The technical scheme adopted in the previous step has the beneficial effects that the size and the quantity of microcracks in the final ceramic aluminum titanate can be balanced against the expansion caused by temperature change and the contraction caused by cold through the grading of the particle sizes of the mullite powder, the fused quartz powder and the secondary ceramic powder, the change of the ceramic along with the volume is avoided, and the uniform distribution without microcracks and high strength are realized; the mullite powder and the fused quartz form a framework in proportion and are distributed around the aluminum titanate, so that the limitation and fixation of microcracks in the aluminum titanate are effectively realized, the expansion of the microcracks is avoided when the microcracks expand and contract along with the temperature change, and the thermal shock performance of the ceramic is improved; meanwhile, the ordered particle size distribution in the ceramic is realized, the clearance in the unit volume of the ceramic is small, and the reduction of the water absorption of the ceramic is facilitated.

Further, the ceramic slurry is subjected to heat treatment at a first heat treatment temperature and a second heat treatment temperature, wherein the first heat treatment temperature is 950-1050 ℃, the heat treatment time is 2-5 hours, and the temperature rise rate of 950-1050 ℃ is 2-3 ℃/min. (ii) a Namely, the heat treatment time comprises temperature rise time and constant temperature time, and the constant temperature is preferably kept at 1000 ℃; the second heat treatment temperature is 1350-1550 ℃, and the heat treatment time is 2.5-3.5 h.

By the last stepThe technical scheme has the beneficial effects that the aluminum titanate ceramic is formed in the prepared first ceramic powder firstly through heat treatment including a first heat treatment temperature and a second heat treatment temperature, the particle size of the aluminum titanate ceramic is 3-5 um, and the particle size is uniform; through the sintering temperature and the heating rate, the aluminum titanate particles are favorably distributed at 3-5 um, the internal microcracks of the ceramic are uniformly distributed at intervals, the size and the size are moderate, the thermal shock property is finally improved, and the thermal expansion coefficient is-0.5-1.5 multiplied by 10^-6/℃。

Detailed Description

In order to better understand the technical solution of the present invention, the following embodiments are provided to further explain the present invention.

Example 1:

one aspect of the present disclosure provides a ceramic, which is prepared from the following raw materials: the first alumina powder, the second alumina powder, mullite powder, fused quartz, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium oxide; the average particle size of the first alumina powder is larger than that of the second alumina powder;

the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 1.5 um; the water absorption of the ceramic is 0.2%; coefficient of thermal expansion of-0.5X 10^-6/° c; the thermal shock resistance is that the thermal shock resistance is not cracked after 50 times of quenching circulation at the temperature of 650-25 ℃;

the ceramic comprises 70% aluminum titanate particles, i.e., the aluminum titanate comprises 70% of the total mass of the ceramic; the mullite powder accounts for 10% of the total mass of the ceramic; the fused quartz accounts for 2% of the total mass of the ceramic; the other components account for 18 percent of the total mass of the ceramic.

In another aspect of the present invention, there is provided a method for preparing a ceramic, including the steps of: mixing and grinding alumina powder, titanium dioxide, magnesium hydroxide, magnesium oxide, talc and iron oxide which are weighed according to the formula proportion with water in ball milling equipment to prepare ceramic slurry, wherein the ball milling time is 4 hours, the granularity of the ceramic slurry is D50 which is more than or equal to 3.5 mu m, and then screening the ceramic slurry with 80-120 meshes;

the granularity D50 of the alumina powder is 55% of the total solid addition mass of the part with the granularity of 2-5 mu m; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 0.8 percent of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and the titanium dioxide accounts for 40.2 percent of the total solid addition mass; the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide respectively account for 1.2 percent, 0.8 percent, 1.5 percent and 0.5 percent of the total solid adding mass;

the ratio of the particle size of the talc to the particle size of the alumina powder is 3: 10; the ratio of the particle size of the magnesium oxide, the magnesium hydroxide and the iron oxide to the particle size of the alumina powder is 2: 10.

Carrying out secondary preparation on the ceramic slurry; the secondary preparation process of the ceramic slurry comprises the following specific steps: drying, crushing or spray drying the ceramic slurry to prepare primary ceramic powder; screening the primary ceramic powder to obtain a material with the grain size smaller than 100 meshes, carrying out heat treatment, and then grinding and screening the material with the grain size smaller than 100 meshes again to obtain first ceramic powder; mixing zirconium oxide, the first ceramic powder, mullite powder, fused quartz and water, adding the mixture into a grinding device, and carrying out ball milling, wherein the mass ratio of solid materials to water is 20%, the granularity of the ceramic slurry prepared after 4 hours is 2.5-4 mu m, PVA is added as a binder, and the addition amount is 0.3% of the solid mass in the secondary preparation process, so that the secondary preparation of the ceramic slurry is completed; the ceramic slurry is subjected to heat treatment at a first heat treatment temperature and a second heat treatment temperature, wherein the first heat treatment temperature is 950-1050 ℃, the heat treatment time is 3.83 hours, and the temperature rise rate of 950-1050 ℃ is 2 ℃/min; the second heat treatment temperature is 1350 ℃, and the heat treatment time is 3.5 h.

The ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 5:1, and the part accounts for 28 percent of the addition amount of the total mullite powder; the ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 30:1, and the part accounts for 72 percent of the total addition amount of the mullite powder;

the ratio of the particle size of the fused quartz powder to the particle size of the secondary ceramic powder is 5:1, and the part accounts for 28 percent of the total addition amount of the fused quartz powder; the ratio of the particle size of the fused quartz powder to the particle size of the secondary ceramic powder is 30:1, and the part accounts for 72 percent of the total addition amount of the fused quartz powder;

filtering the ceramic slurry after the secondary preparation by using a 100-mesh screen, granulating by using spray drying equipment to prepare ceramic powder, and screening the ceramic powder with 60-250 meshes to prepare a ceramic blank; drying and sintering the ceramic blank to obtain ceramic; the granulated ceramic powder is sieved to obtain 60-250 mesh intermediate powder, and the intermediate powder is subjected to dry pressing and fettling to obtain a ceramic blank; the temperature for preparing the ceramic by sintering the ceramic blank is 1370 ℃, and the cooling rate between 900 ℃ and 1350 ℃ is 2 ℃/min during temperature rising.

Example 2

The same contents of this embodiment as embodiment 1 are not described again;

one aspect of the present embodiments provides a ceramic prepared from the following raw materials: the aluminum oxide powder comprises first aluminum oxide powder, second aluminum oxide powder, mullite powder, fused quartz, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium silicate;

the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 3 um;

the water absorption of the ceramic is 1.1%; coefficient of thermal expansion of 1X 10^-6/° c; the ceramic comprises 82.5% aluminum titanate particles, i.e., the aluminum titanate comprises 82.5% of the total mass of the ceramic; the mullite powder accounts for 7.5 percent of the total mass of the ceramic; the fused quartz accounts for 1% of the total mass of the ceramic; the other components account for 9 percent of the total mass of the ceramic.

In another aspect of the embodiment, a ceramic preparation method is provided, wherein the ball milling time is 18 hours, the particle size of the obtained ceramic slurry is D50 which is more than or equal to 3.5 mu m, and then 80-120 meshes of ceramic slurry are sieved;

the granularity D50 of the alumina powder is about 46 percent of the total solid adding mass of the part with the granularity of 2-5 mu m; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 1.4 percent of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 45.6 percent of the total solid addition mass;

the magnesium hydroxide, the magnesium oxide, the talc and the iron oxide respectively account for 2%, 1.5%, 3.5% and 1% of the total solid adding mass;

the ratio of the particle size of the talc to the particle size of the alumina powder is 5: 10; the ratio of the particle size of the magnesium oxide, the magnesium hydroxide and the iron oxide to the particle size of the alumina powder is 3.5: 10.

The ceramic slurry is subjected to heat treatment at a first heat treatment temperature and a second heat treatment temperature, wherein the first heat treatment temperature is 950-1050 ℃, the heat treatment time is 2.66 hours, and the temperature rise rate of 950-1050 ℃ is 2.5 ℃/min; the second heat treatment temperature is 1450 ℃, and the heat treatment time is 3 hours.

Mixing zirconium silicate, the first ceramic powder, mullite powder and molten quartz water, adding the mixture into a grinding device for ball milling, wherein the mass ratio of solid materials to water is 40%, preparing ceramic slurry with the granularity D50 of 2.5-4 mu m after 14 hours, adding PVA as a binder, and finishing the secondary preparation of the ceramic slurry, wherein the addition amount of the PVA is 0.75% of the solid mass in the secondary preparation process;

the ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 7.5:1, and the part accounts for 30 percent of the addition amount of the total mullite powder; the ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 49:1, and the part accounts for 70 percent of the total addition amount of the mullite powder;

the proportion of the granularity in the fused quartz powder to the granularity of the secondary ceramic powder is 7.5:1, and the proportion accounts for 30 percent of the addition amount of the total fused quartz powder; the ratio of the particle size of the fused quartz powder to the particle size of the secondary ceramic powder is 49: part 1 accounts for 70% of the total addition amount of the fused quartz powder;

the temperature for preparing the ceramic by sintering the ceramic blank is 1435 ℃, and the cooling rate between 900 and 135 ℃ is 3 ℃/min when the temperature is raised.

Example 3:

the same contents of this embodiment as embodiment 1 are not described again;

one aspect of the present embodiments provides a ceramic prepared from the following raw materials: the first alumina powder, the second alumina powder, mullite powder, fused quartz, magnesium hydroxide, magnesium oxide, talc and iron oxide;

the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 5 um;

the water absorption of the ceramic is 2%; coefficient of thermal expansion of 1.5X 10^-6/° c; the ceramic comprises 95% aluminum titanate particles, i.e., the aluminum titanate comprises 95% of the total mass of the ceramic; the mullite powder accounts for 2% of the total mass of the ceramic; the fused quartz accounts for 0.2% of the total mass of the ceramic; the other components account for 2.8 percent of the total mass of the ceramic.

Another aspect of the present embodiment provides a method of preparing a ceramic,

ball milling is carried out for 4-24 h to obtain ceramic slurry with the particle size D50 being more than or equal to 3.5 mu m, and then 80-120 meshes of ceramic slurry is sieved;

the part of the alumina powder with the granularity D50 of 2-5 mu m accounts for 50% of the total solid addition mass; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 0.4 percent of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 48.6 percent of the total solid addition mass;

the magnesium hydroxide, the magnesium oxide, the talcum and the iron oxide account for 0.3 percent, 0.15 percent, 0.45 percent and 0.1 percent of the total solid adding mass respectively;

the ratio of the particle size of the talc to the particle size of the alumina powder is 7: 10; the ratio of the particle size of the magnesium oxide, the magnesium hydroxide and the iron oxide to the particle size of the alumina powder is 5: 10.

The ceramic slurry is subjected to heat treatment at a first heat treatment temperature and a second heat treatment temperature, wherein the first heat treatment temperature is 950-1050 ℃, the heat treatment time is 5.55h, and the temperature rise rate of 950-1050 ℃ is 3 ℃/min; the second heat treatment temperature is 1550 ℃, and the heat treatment time is 2.5 h.

Mixing the first ceramic powder with mullite powder, fused quartz and water, adding the mixture into a grinding device, carrying out ball milling, wherein the mass ratio of a solid material to water is 60%, preparing ceramic slurry with the granularity D50 of 2.5-4 mu m after 24 hours, adding PVA as a binder, and finishing the secondary preparation of the ceramic slurry, wherein the addition amount of the PVA is 0.3% of the solid mass in the secondary preparation process;

the ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 10:1, and the part accounts for 32% of the addition amount of the total mullite powder; the ratio of the grain size of the mullite powder to the grain size of the secondary ceramic powder is 68:1, and the part accounts for 68% of the total addition amount of the mullite powder;

the proportion of the granularity in the fused quartz powder to the granularity of the secondary ceramic powder is 10:1, and the part accounts for 32% of the total addition amount of the fused quartz powder; the proportion of the granularity in the fused quartz powder to the granularity of the secondary ceramic powder is 68:1, and the fused quartz powder accounts for 68% of the total addition amount of the fused quartz powder;

the temperature for preparing the ceramic by sintering the ceramic blank is 1500 ℃, and the cooling rate is 5 ℃/min between 900 ℃ and 1350 ℃ when the temperature is increased.

Example 4:

the same contents of this embodiment as embodiment 1 are not described again;

one aspect of the present disclosure provides a ceramic, which is prepared from the following raw materials: the first alumina powder, the second alumina powder, mullite powder, fused quartz, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium oxide;

the ceramic has a plurality of cracks distributed at intervals, and the length of each crack is 5um

The ceramic comprises 70% aluminum titanate particles, i.e., the aluminum titanate comprises 70% of the total mass of the ceramic; the mullite powder accounts for 15% of the total mass of the ceramic; the fused quartz accounts for 2% of the total mass of the ceramic; the other components account for 13 percent of the total mass of the ceramic.

In another aspect of this embodiment, a method for preparing a ceramic is provided, which includes the steps of: mixing and grinding alumina powder, titanium dioxide, mullite powder, fused quartz powder, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium oxide which are weighed according to the formula proportion with water in ball milling equipment to prepare ceramic slurry, wherein the ceramic slurry does not need to be prepared secondarily;

the part of the alumina powder with the granularity D50 of 2-5 mu m accounts for 40% of the total solid addition mass; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 1 percent of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 35% of the total solid addition mass;

the magnesium hydroxide, the magnesium oxide, the talc, the iron oxide and the zirconium oxide respectively account for 1.7%, 1%, 2.5%, 0.5% and 1% of the total solid adding mass;

the mullite powder accounts for 15% of the total mass of the ceramic; the fused quartz accounts for 2% of the total mass of the ceramic;

the ratio of the particle sizes of the mullite powder and the fused quartz powder to the particle size of the alumina powder is 10: 1; ball milling is carried out for 4 hours to obtain ceramic slurry with the granularity D50 of 2.8-5 mu m, and then PVA is added as a binder, wherein the addition amount is 0.3% of the mass of the solid; then granulating the ceramic slurry filtered by a 100-mesh screen by adopting spray drying equipment to prepare ceramic powder, and screening the ceramic powder with 60-250 meshes to prepare a ceramic blank; drying and sintering the ceramic blank to obtain ceramic; sieving the granulated ceramic powder to obtain 60-250-mesh intermediate powder, performing dry pressing, and trimming to obtain a ceramic blank; the temperature for preparing the ceramic by sintering the ceramic blank is 1350 ℃, and the cooling rate between 1350 ℃ and 1100 ℃ is more than or equal to 3 ℃/min during cooling.

Example 5:

the same contents of this embodiment as embodiment 1 are not described again;

one aspect of the present invention provides a ceramic, which is prepared from the following raw materials: the aluminum oxide powder comprises first aluminum oxide powder, second aluminum oxide powder, mullite powder, fused quartz, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium silicate;

the ceramic is provided with a plurality of cracks distributed at intervals, and the length of each crack is 10 mu m; the water absorption of the ceramic is 1%; coefficient of thermal expansion of 1X 10^-6/℃；

The ceramic comprises 78% aluminum titanate particles, i.e., the aluminum titanate comprises 78% of the total mass of the ceramic; the mullite powder accounts for 7% of the total mass of the ceramic; the fused quartz accounts for 1% of the total mass of the ceramic; the other components account for 14 percent of the total mass of the ceramic.

In another aspect of the present invention, there is provided a method for preparing a ceramic, including the steps of: mixing and grinding alumina powder, titanium dioxide, mullite powder, fused quartz powder, magnesium hydroxide, magnesium oxide, talc, iron oxide and zirconium silicate which are weighed according to the formula proportion with water in ball milling equipment to prepare ceramic slurry, wherein the ceramic slurry does not need to be prepared secondarily;

the granularity D50 of the alumina powder is that the part with the granularity of 2-5 mu m accounts for 45% of the total solid addition mass; the part of the alumina powder with the granularity D50 not more than 0.5 mu m accounts for 2 percent of the total solid addition mass;

the titanium dioxide is rutile type, the granularity D50 is less than or equal to 0.7 mu m, and accounts for 39% of the total solid addition mass;

the magnesium hydroxide, the magnesium oxide, the talc, the iron oxide and the zirconium silicate respectively account for 1.5%, 1%, 2%, 0.2% and 1% of the total solid addition mass;

the mullite powder accounts for 7% of the total mass of the ceramic; the fused quartz accounts for 1% of the total mass of the ceramic;

the ratio of the particle sizes of the mullite powder and the fused quartz powder to the particle size of the alumina powder is 49: 1; the ball milling time is 24 hours, the granularity D50 of the obtained ceramic slurry is 2.8-5 mu m, then PVA is added as a binder, and the addition amount is 0.3% of the mass of the solid; then granulating the ceramic slurry filtered by a 100-mesh screen by adopting spray drying equipment to prepare ceramic powder, and screening the ceramic powder with 60-250 meshes to prepare a ceramic blank; drying and sintering the ceramic blank to obtain ceramic; sieving the granulated ceramic powder to obtain 60-250-mesh intermediate powder, performing dry pressing, and trimming to obtain a ceramic blank; the temperature for preparing the ceramic by sintering the ceramic blank is 1520 ℃, and the cooling rate between 1520 ℃ and 1100 ℃ is more than or equal to 3 ℃/min during cooling.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the features described above have similar functions to (but are not limited to) those disclosed in this application.