SiC窑具材料氧化动力学方程的研究

RESEARCHES OF OXIDATIVE KINETICS OF SiC KILN FURNITURE

在硅微粉结合的SiC窑具材料中添加少量的铁矿渣矿化剂,使窑具在高温下形成一定量的液相,能使体积效应大的α-方石英转化成体积效应小的α-鳞石英,降低窑具的体积效应和提高热稳定性。同时形成的液相能使S i C表面形成一层致密的保护膜,堵塞气孔,隔离O2与SiC的接触,降低在界面上进行的氧化反应速度,以达到抗氧化的目的。实验结果表明:添加0.4%铁矿渣矿化剂的氧化度最小(G=6.1x10-5),确定0.4%为最佳的铁矿渣加入量。在1300℃下铁矿渣添加量分别为0和0.4wt%时的氧化动力学方程分别为:F(G1)=3.17×10-9,F(G2)=1.

The iron-ore slag of different contents was added to SiC kiln furniture bonded with fine silicon powder. Some amount of liquid, formed by Fe2O3 at high temperature, can make a-cristobalite crystallized from the fine silicon powder convert to stable α -tridymite so as to improve the heat-stability of kiln furniture and then to prolong its lifetime. The influences of iron-ore slag of different contents on the mechanical properties and oxidation of kiln furniture were discussed. The results show that the best proportion of the iron-ore slag added is to be 0.4wt%, with the oxidisability is 0.0061% after oxidation for 12 h. The oxidation equation at 1300℃ were F（G1）=3.17 × 10^-9 and F（G2）=1.75 × 10^-9 （with 0.4wt% iron-ore slag） respectively.