氮化硅陶瓷直接凝固注模成型的凝固动力学

Solidification Kinetics of Silicon Nitride Suspension by Direct Coagulation Casting

直接凝固注模成型（ＤＣＣ）是一种新的近净尺寸陶瓷成型工艺；它是通过可控制反应速率的酶催化反应来实现浆料原位固化的．本文将悬浮体流变学与陶瓷浆料的成型工艺学有机结合，通过陶瓷浆料的动态弛豫实验，研究了Ｓｉ３Ｎ４浆料ＤＣＣ成型的凝固动力学．结果表明：“凝固时间”可以成功地描述陶瓷浆料的凝固过程，动态弛豫实验为陶瓷浆料的凝固动力学提供了一条简便可行的研究方法．在Ｓｉ３Ｎ４浆料ＤＣＣ成型工艺条件优化的基础上，制备出了气孔分布均匀的Ｓｉ３Ｎ４坯体．

Direct coagulation casting (DCC) is a novel-net-shape method for forming ceramic green bodies, which is based on the principle of the in-situ coagulation of a powder suspension via a reaction-rate-controlled enzyme-catalyzed reaction after casting. Combining the rheology with the shape-forming technology of ceramic suspension, the coagulation kinetics of silicon nitride suspension for DCC forming were investigated. The experimental results indicate that the coagulation kinetics can be successfully studied by the dynamic relaxation experiments in terms of' coagulation time',which provides a convenient and practicable way to research the coagulation kinetics of ceramic suspension. After optimizing the processing conditions of the silicon nitride suspension for DCC forming, a green body with uniform, narrow and unimodal pore size distribution was prepared.