水溶性胶态成型工艺制备氮化硅耐磨结构陶瓷

以氮化硅粉末为原料, 采用水溶性胶态成型工艺制备高耐磨氮化硅陶瓷. 采用正交设计的方法来优化制备高品质注浆料, 并研究了掺杂分散剂后Zeta电位的变化. 同时, 还对氮化硅陶瓷烧结体的显微结构、力学性能和耐磨性能进行了研究. 结果表明: 当氮化硅浆料中固相体积分数为45%时, 可制得体积密度较高的精细氮化硅陶瓷材料, 断裂韧性可达7.21MPa·m^1/2, 硬度为9.30GPa. 通过抗耐磨损实验研究表明: 干摩擦条件下, 氮化硅陶瓷发生了晶粒脆性断裂和脱落; 水润滑条件下, 摩擦表面产生了氢氧化硅 反应膜, 降低了磨损, 主要是化学腐蚀磨损.

Preparation of Silicon Nitride Ceramics with High Wear Resistance by Aqueous Colloidal Process

Advanced silicon nitride ceramics with high wear resistance were fabricated by colloidal process. Orthogonal design was utilized to optimize the process parameters.The change of Zeta potential for Si3N4 particles after adding dispersant was analyzed. Furthermore, the microstructure, mechanical properties and wear resistance of silicon nitride ceramics were investigated. The results indicate that the green body with high density can be formed when the volume fraction of solid phase of silicon nitride slurry is equal to 45%. And silicon nitride ceramics with fracture toughness of 7.21MPa·m^1/2, hardness of 9.30GPa is obtained in the optimum condition. The friction and wear tests show that silicon nitride ceramics happen to crisp rupture and break off in the dry condition; while in the water-lubricated condition, the film of Si(OH)₄ is formed on the friction surface, and the wear mechanism is mainly chemical fretting wear.