保温时间对不同粒度氟硅云母玻璃粉体烧结行为的影响

目的研究保温时间变化对2种不同粒度氟硅云母玻璃陶瓷粉体烧结后的收缩率及微观形貌的影响。方法制备颗粒平均粒度分别为4．5μm和72．8μm的氟硅云母玻璃粉体，经冷等静压成型后，在设定相同烧结温度、升温速率，不同的保温时间下进行烧结。结果2种粒度玻璃陶瓷的收缩率随着保温时间的增加均呈现升高趋势，起始阶段升高幅度大，随着保温时间的延长而逐渐减缓，最终到达平衡状态，但二者升高的幅度和时间有所差别，小粒度粉体的收缩率总体高于粒度较大者，且其达到最大收缩率的时间也较粒度大者明显缩短。结论小粒度粉体对热效应较为敏感，其最佳保温时间为1h，而粒度较大者则为4h。

Effects of the heat-preserving-time on sintering behaviors of fluorosilicic mica powder of different particle sizes

Objective To investigate the effects of heat-preserving-time on sintering shrinkage and microstructure of dental fluorosilicic mica glass powder of two different particle sizes. Methods Fluorosilicic mica glass powder of two different particle sizes was prepared. The powder with an average particle diameter of 72.8μm was named P0 and that with an average diameter of 4.5 μm was named Pro. P0 and Pm were molded by cool isostatic pressing technique and then sintered at the same temperature, same calefactive velocity but different heat-- preserving time. Results The shrinkages of both P0 and Pm were increased and the increasing velocity was slower and slower with prolongation of the heat-preserving-time; the shrinkage of Pm was evidently higher than that of P0; Pm needed much shorter heat-preserving-time to achieve ultimate compactness than the bigger one. Conclusion The glass powder with smaller particle size was much sensitive to heat-preserving, whose proper heat-preserving time should be 1 hour, while that of glass powder with larger particle size should be 4 hours.