阅读说明：本技术 一种利用天然矿物为原料的氮化硅晶须-氮化铝-刚玉三元复合陶瓷材料及其制备方法 (Silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials and preparation method thereof ) 是由 劳新斌 徐笑阳 江伟辉 梁健 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种利用天然矿物为原料的氮化硅晶须-氮化铝-刚玉三元复合陶瓷材料,包括基料和结合剂,所述基料的组成为铝硅酸盐矿物65～85wt％、金属铝粉10～30wt％、金属硅粉5～10wt％,所述结合剂的用量为基料的6～12wt％。此外,还公开了上述利用天然矿物为原料的氮化硅晶须-氮化铝-刚玉三元复合陶瓷材料的制备方法。本发明采用天然铝硅酸盐矿物-金属铝粉-金属硅粉为原料体系,通过原位合成的方式引入氮化硅晶须、氮化铝和刚玉,不仅节约了原料成本,简化了制备工艺,而且有效解决了现有技术工业粉料和骨料不易混匀的问题,提高了刚玉基复合陶瓷材料的品质与性能,有利于推广应用和行业技术的进步与发展。(The invention discloses a silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material taking natural minerals as raw materials, which comprises a base material and a bonding agent, wherein the base material comprises 65-85 wt% of aluminosilicate minerals, 10-30 wt% of metal aluminum powder and 5-10 wt% of metal silicon powder, and the amount of the bonding agent is 6-12 wt% of the base material. In addition, the preparation method of the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using the natural minerals as the raw materials is also disclosed. According to the invention, natural aluminosilicate mineral-metal aluminum powder-metal silicon powder are used as a raw material system, and silicon nitride whiskers, aluminum nitride and corundum are introduced in an in-situ synthesis manner, so that the raw material cost is saved, the preparation process is simplified, the problem that industrial powder and aggregate are not easy to mix uniformly in the prior art is effectively solved, the quality and performance of the corundum-based composite ceramic material are improved, and the popularization and application and the progress and development of industrial technology are facilitated.)

1. A silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials is characterized in that: the aluminum silicate aluminum powder aluminum.

2. The silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials according to claim 1, characterized in that: the aluminosilicate mineral is one, two or three of natural kaolin, ball clay, andalusite, sillimanite, kyanite and bauxite.

3. The silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials according to claim 1, characterized in that: the granularity of the aluminosilicate mineral is 80-325 meshes; the granularity of the metal aluminum powder is 100-700 meshes; the particle size of the metal silicon powder is 325-700 meshes.

4. The silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials according to claim 1, characterized in that: the binding agent is one or the combination of water, dextrin, waste paper pulp liquid and PVA solution with the concentration of 5 wt%.

5. A method for preparing the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material by using natural minerals as raw materials according to any one of claims 1 to 4, which is characterized by comprising the following steps of: mixing the base materials, adding a bonding agent, and uniformly mixing; and (3) pressing, molding and drying to obtain a green body, sintering under the conditions of nitrogen atmosphere and silicon nitride aggregate embedding, and firing to obtain the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material.

6. The method for preparing the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material by using natural minerals as raw materials according to claim 5, characterized in that: the moisture content of the dried green body is less than 1%.

7. The method for preparing the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material by using natural minerals as raw materials according to claim 5, characterized in that: the sintering temperature is 1350-1600 ℃, and the sintering time is 1-3 h.

Technical Field

The invention relates to the technical field of ceramic materials, in particular to a silicon nitride whisker-aluminum nitride-corundum composite ceramic material and a preparation method thereof.

Background

The corundum ceramic is a material with wide application, has the characteristics of high strength, good corrosion resistance, high refractoriness and the like, and can be used for high-temperature applications such as crucibles, roller beds and the like. However, corundum ceramics has the disadvantages of high thermal expansion coefficient, poor toughness, poor thermal shock resistance and the like, so when the corundum ceramics is used as high-temperature structural ceramics, the dimensional specification is limited to a certain extent. This is because the larger the gauge, the poorer the thermal shock resistance of the material. The silicon nitride and the aluminum nitride have the advantages of high thermal conductivity, low expansion, high thermal shock resistance and the like, and can just make up the defects in the aspect of the performance of corundum ceramics, so that the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material is a complex phase ceramic material integrating the advantages of the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material and has wide application in the fields of refractory materials, grinding materials and the like.

At present, in the prior art, the preparation of corundum-based composite ceramic materials mainly takes industrial silicon nitride powder, aluminum nitride powder and corundum powder as raw materials, namely, corundum powder is taken as aggregate, and silicon nitride powder and aluminum nitride powder are mixed for modification. The material system generally has the problems of high raw material cost, uneven mixing, uneven performance and the like. Even though the research adopts the mode of in-situ synthesis of whiskers to introduce silicon nitride and other raw materials, the aluminum source and the silicon source still adopt industrial raw materials, so that the product cost is high, the forming is difficult, and the product yield is low.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material which takes natural minerals as raw materials. The invention also aims to provide a preparation method of the silicon nitride whisker-aluminum nitride-corundum composite ceramic material by using natural minerals as raw materials.

The purpose of the invention is realized by the following technical scheme:

the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials comprises 65-85 wt% of aluminosilicate minerals, 10-30 wt% of metal aluminum powder and 5-10 wt% of metal silicon powder, and a bonding agent is 6-12 wt% of the base materials.

Furthermore, the aluminosilicate mineral is one, two or three of natural kaolin, ball clay, andalusite, sillimanite, kyanite and bauxite.

Further, the granularity of the aluminosilicate mineral is 80-325 meshes; the granularity of the metal aluminum powder is 100-700 meshes; the particle size of the metal silicon powder is 325-700 meshes.

In the scheme, the binding agent is one or a combination of water, dextrin, waste paper pulp liquid and 5 wt% PVA solution.

The other purpose of the invention is realized by the following technical scheme:

the preparation method of the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material using natural minerals as raw materials provided by the invention comprises the following steps: mixing the base materials, adding a bonding agent, and uniformly mixing; and (3) pressing, molding and drying to obtain a green body, sintering under the conditions of nitrogen atmosphere and silicon nitride aggregate embedding, and firing to obtain the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material.

Furthermore, the moisture content of the dried green body prepared by the preparation method is less than 1%.

In the scheme, the sintering temperature is 1350-1600 ℃, and the sintering time is 1-3 h.

The invention has the following beneficial effects:

(1) the invention adopts a raw material system of natural aluminosilicate mineral-metal aluminum powder and adopts a mode of silicon powder direct nitridation to synthesize Si in advance₃N₄As crystal nucleus of crystal whisker, and replacing metal silicon by the reaction of metal aluminum powder and silicon dioxide in mineral, reacting the metal silicon with the silicon dioxide in situ to generate SiO gas-phase product, reacting the SiO gas-phase product with nitrogen, and synthesizing Si from the synthesized Si in advance₃N₄Generating a large amount of silicon nitride whiskers in situ on the crystal nucleus; metal aluminium powder and nitrogen gas in atmosphereReacting to generate aluminum nitride in situ; the silicon dioxide in the aluminosilicate mineral is continuously replaced by the aluminum powder to be reacted and disappear, and the rest aluminum oxide is synthesized in situ to obtain the corundum. Because the target products (namely the silicon nitride whisker and the aluminum nitride) synthesized in situ can be uniformly distributed among the corundum particles, the problem that industrial powder and aggregate are not easy to mix uniformly in the prior art is effectively solved, and the performance of the silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material is greatly improved.

(2) The invention mainly uses natural minerals, wherein ball clay and kaolin have good plasticity and are beneficial to improving the forming performance, thereby obviously improving the yield of products; in addition, the used natural minerals have the advantages of large reserves, wide distribution, low price and the like, and are beneficial to reducing the product cost. The used metal aluminum powder has a lower melting point, can form a liquid phase at a lower sintering temperature and disperse in a blank, and is not only favorable for sintering materials, but also favorable for solving the problem of uneven performance.

(3) The silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material synthesized in situ has good thermal shock resistance, low firing shrinkage and high mechanical strength, and the main performance indexes are as follows: the addition amount of the natural minerals is more than or equal to 50 percent, the firing shrinkage is less than 2 percent, the thermal conductivity is more than 10W/(m.K), the breaking strength is more than or equal to 40MPa, the cracking does not occur after the thermal shock resistance cycle of 1100 ℃ to room temperature is carried out for 30 times, and the heat preservation is carried out for 1 hour at 1400 ℃ without softening and deforming.

(4) The invention has the advantages of easily obtained raw materials, simple process and low sintering temperature, and has important significance for improving the quality of the corundum-based ceramic material and saving the product cost, thereby having wide market prospect and being beneficial to popularization and application and the improvement and development of industrial technology.

Drawings

The invention will now be described in further detail with reference to the following examples and the accompanying drawings:

FIG. 1 is an X-ray diffraction spectrum of a silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material prepared by the embodiment of the invention;

FIG. 2 is a secondary electron image of a silicon nitride whisker-aluminum nitride-corundum ternary composite ceramic material prepared by the embodiment of the invention.

Detailed Description