Fe包覆Si_3N_4金属陶瓷相反应热力学分析

Thermodynamic analysis of phase reaction of Fe coating Si_3N_4 cermet

研究非均相沉淀热还原法制备Fe包覆α-Si3N4复合粉末常压烧结界面反应特性,并进行热力学分析。研究结果表明:在1 600℃下烧结时,α-Si3N4部分转变为β-Si3N4,Fe相消失,转而生成FeSi化合物;在1 700℃下烧结时,α-Si3N4基本转变为β-Si3N4,FeSi化合物消失,Fe相重新出现;在烧结过程中,FeSi化合物或Fe晶粒发生明显长大,呈圆球状分布在Si3N4晶粒之间,实验结果可通过热力学分析进行解释。

The interfacial reaction characteristics of pressure sintering of Fe coating α-Si3N4 prepared by heterogeneous precipitation-thermal reduction method was studied,and the thermodynamic analysis was carried out.The results show that when the sintering temperature is 1 600 ℃,parts of α-Si3N4 turns to β-Si3N4,and Fe phase disappears and turns into FeSi compounds;When the sintering temperature is 1 700 ℃,most α-Si3N4 changes into β-Si3N4,and FeSi compounds disappear and Fe phase reappears.During the sintering process,FeSi compounds and Fe grains distributed between the Si3N4 grains obviously grow up.The experimental results can be explained by the thermodynamic analysis.