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Method for preparing high-strength and high-thermal-conductivity silicon nitride ceramic through two-step sintering
The invention belongs to the field of ceramic preparation, and particularly relates to a method for preparing high-strength and high-thermal-conductivity silicon nitride ceramic through two-step sintering. The method comprises the following steps: mixing silicon nitride powder and a sintering aid with an organic solvent according to a certain ratio, granulating, pressing, degreasing, pretreating for 1-5 hours under the conditions of low temperature, normal pressure and nitrogen introduction, and sintering at a high temperature under the nitrogen pressure of 0.9-10 MPa. In the first-step pretreatment, the content of the magnesium oxide sintering aid is adjusted according to the oxygen content of the silicon nitride powder, the oxygen content of a green body is reduced before sintering by utilizing the low-temperature reaction characteristic of magnesium oxide and silicon dioxide on the surface of the silicon nitride powder, and then the second-step air pressure sintering is performed. Compared with the sintered body which is not pretreated, the silicon nitride ceramic subjected to two-step sintering has higher density, the total oxygen content and the second phase content are obviously reduced, and the silicon nitride ceramic of which the thermal conductivity is greater than 90W/m.K and the bending strength is greater than 750MPa can be prepared.
本发明属于陶瓷制备领域，具体涉及一种两步烧结制备高强高导热氮化硅陶瓷的方法。该方法是将氮化硅粉体和烧结助剂按一定比例与有机溶剂混合后，经过造粒、压制、脱脂后，首先在低温、常压、通氮气条件下预处理1～5h，随后在高温、0.9～10MPa氮气压力下进行烧结。在第一步预处理中，根据氮化硅粉体氧含量调节氧化镁烧结助剂含量，利用氧化镁与氮化硅粉体表面二氧化硅低温反应特性，烧结前降低坯体氧含量，再进行第二步气压烧结。与未经过预处理的烧结体相比，经过两步烧结的氮化硅陶瓷具有更高的致密度，总氧含量和第二相含量有明显减少，可制备热导率大于90W/m·K，抗弯强度大于750MPa的氮化硅陶瓷。
Method for preparing high-strength and high-thermal-conductivity silicon nitride ceramic through two-step sintering
The invention belongs to the field of ceramic preparation, and particularly relates to a method for preparing high-strength and high-thermal-conductivity silicon nitride ceramic through two-step sintering. The method comprises the following steps: mixing silicon nitride powder and a sintering aid with an organic solvent according to a certain ratio, granulating, pressing, degreasing, pretreating for 1-5 hours under the conditions of low temperature, normal pressure and nitrogen introduction, and sintering at a high temperature under the nitrogen pressure of 0.9-10 MPa. In the first-step pretreatment, the content of the magnesium oxide sintering aid is adjusted according to the oxygen content of the silicon nitride powder, the oxygen content of a green body is reduced before sintering by utilizing the low-temperature reaction characteristic of magnesium oxide and silicon dioxide on the surface of the silicon nitride powder, and then the second-step air pressure sintering is performed. Compared with the sintered body which is not pretreated, the silicon nitride ceramic subjected to two-step sintering has higher density, the total oxygen content and the second phase content are obviously reduced, and the silicon nitride ceramic of which the thermal conductivity is greater than 90W/m.K and the bending strength is greater than 750MPa can be prepared.
本发明属于陶瓷制备领域，具体涉及一种两步烧结制备高强高导热氮化硅陶瓷的方法。该方法是将氮化硅粉体和烧结助剂按一定比例与有机溶剂混合后，经过造粒、压制、脱脂后，首先在低温、常压、通氮气条件下预处理1～5h，随后在高温、0.9～10MPa氮气压力下进行烧结。在第一步预处理中，根据氮化硅粉体氧含量调节氧化镁烧结助剂含量，利用氧化镁与氮化硅粉体表面二氧化硅低温反应特性，烧结前降低坯体氧含量，再进行第二步气压烧结。与未经过预处理的烧结体相比，经过两步烧结的氮化硅陶瓷具有更高的致密度，总氧含量和第二相含量有明显减少，可制备热导率大于90W/m·K，抗弯强度大于750MPa的氮化硅陶瓷。
Method for preparing high-strength and high-thermal-conductivity silicon nitride ceramic through two-step sintering
一种两步烧结制备高强高导热氮化硅陶瓷的方法
QIN MINGLI (author) / WANG YUELONG (author) / TIAN JIANJUN (author) / WU HAOYANG (author) / JIA BAORUI (author) / ZHANG YIMING (author) / ZHANG LIN (author) / QU XUANHUI (author)
2021-11-12
Patent
Electronic Resource
Chinese
IPC:
C04B
Kalk
,
LIME
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