复合添加剂对熔融石英陶瓷析晶的影响

以粒径≤0.10 mm的熔融石英粉为主要原料,分别添加相对于熔融石英粉质量1%、2%、3%的复合添加剂B4C-Yb2O3(B4C与Yb2O3的质量比为1:1)或Si3N4-Nd2O3(Si3N4与Nd2O3的质量比为1:1),以聚乙烯醇为结合剂,经搅拌、成型、干燥后,分别于1300、1350和1400℃埋炭(石墨)保温1 h热处理,然后在常温～1200℃对烧后试样进行热膨胀试验,并对其进行XRD分析,以研究复合添加剂B4C-Yb2O3和Si3N4-Nd2O3对熔融石英陶瓷在热处理过程中析晶的影响。结果表明:添加B4C-Yb2O3或Si3N4-Nd2O3对熔融石英热处理过程中的析晶均有不同程度的抑制作用,且B4C-Yb2O3抑制熔融石英析晶的效果比Si3N4-Nd2O3的更好,尤其是在较高的热处理温度下。

Effects of composite additives on crystallization behavior of fused quartz ceramics

Fused quartz ceramics were prepared using fused quartz powder(≤0.10 mm) as main starting material,B4C-Yb2O3 or Si3N4-Nd2O3 with 1:1 of mass ratio as composite additives with dosages of separate 1%(in mass,similarly hereinafter),2% and 3% of fused quartz ceramics powder mass,polyvinyl alcohol as binder,mixing,shaping,drying,and graphite-embedded firing at 1300,1350 and 1400 ℃ for 1 h,respectively.The thermal expansion test from ambient temperature to 1 200 ℃ and XRD analysis of fired specimens were carried out to research the effects of composite additives B4C-Yb2O3 or Si3N4-Nd2O3 on crystallization behavior of fused quartz ceramics during firing.The results indicate that both B4C-Yb2O3 and Si3N4-Nd2O3 inhibit the crystallization to a certain degree,and the former has better inhibiting effect that the latter,especially at higher firing temperatures.