非水解溶胶－凝胶结合碳热还原氮化法制备β-SiAlON 粉体

摘要

This work aims at synthesizing β-SiAlON powder with good properties at lower temperatures.Theβ-SiAlON powder was synthesized by carbonthermal reduction nitridation process,during which the precur-sor gel was synthesized by non-hydrolytic sol-gel method using tetraethoxysilane,anhydrous AlCl3 and di-chloromethane as main starting materials,followed by mixing with carbon black and CaF2 .The effects of precalcined temperatures of dry gel (without precalcination,300 and 500 ℃),carbon black dosages (n(C) n(Al)is 6.50 1,3.25 1 and 2.75 1),synthesis temperatures (1 400,1 450 and 1 500 ℃)and 3%CaF2 addition on the synthesis of the powder were studied by XRD and SEM.The results show that the pre-calcination at 300 ℃ can keep a high activity of the dry gel;β-SiAlON has a relatively higher yield rate in the case of n(C)n(Al)=6.50 1;higher synthesis temperature and 3% CaF2 addition can promote the synthe-sis of β-SiAlON powder;the average size of the powder is 150 nm.%为了在较低温度下合成性能较好的β-SiAlON 粉体，先以正硅酸乙酯、无水氯化铝和二氯甲烷等为原料采用非水解溶胶－凝胶法合成前驱体凝胶，然后与炭黑和 CaF2混合后以碳热还原氮化法合成β-SiAlON 粉体，并采用 XRD 及 SEM研究了干凝胶预焙烧温度（300和500℃）、炭黑用量（n（C）n（Al）分别为6．501、3．251和2．751）、合成温度（1400、1450和1500℃）及添加3％（w）CaF2对粉体合成的影响。结果表明：在300℃下预焙烧能保持干凝胶的高活性；n（C）n（Al）＝6．501时β-SiAlON 合成率较高；提高合成温度和引入3％（w）CaF2能促进β-SiAlON 粉体的合成；合成的β-SiAlON 粉体平均粒径为150 nm。