烧结温度对不同粒度氟硅云母玻璃陶瓷收缩率及微观形貌的影响

Effect of sintering temperature on the shrinkage and microstructure of dental fluorosilicic mica glass-ceramics with different particle size

目的:探讨烧结温度对2 种颗粒粒度氟硅云母微晶玻璃烧结收缩率及微观形貌的影响.方法:选用颗粒平均粒度分别为4.5 μm和72.8 μm的氟硅云母玻璃粉,经冷等静压成型,分别在600～1 000 ℃之间不同温度烧结,比较2 种颗粒尺寸微晶玻璃的收缩率变化及微观形貌的差别.结果:随着烧结温度的增加,2 种粒度玻璃烧结收缩率均增加,但二者收缩率曲线差别明显,粒度较小者收缩率高于粒度较大者,而且体现烧结机制变化的温度转折点亦有显著差别,其微观形貌表现出相同的变化趋势.结论:小粒度氟硅云母玻璃粉体获得的烧结致密度优于大粒度粉体;采用小粒度玻璃粉体中温段加强烧结工艺,可以获得良好的烧结致密度.

Objective:To investigate the effect of sintering temperature on the shrinkage and microstructure of dental fluorosilicic mica glass-ceramic with two different particle size. Methods:Fluorosilicic mica glass powder with average particle diameter of 72.8 μm was named PO and that with average diameter of 4.5 μm was named Pm. PO and Pm were molded by cool isostatic pressing technique and then sintered at different temperatures between 600-1 000 ℃. The shrinkage and microstructure of the sintered blocks of PO and Pm were systematically compared with each other. Results:The shrinkage of PO and Pm blocks were all increased as the temperature ascended. However, the shrinkage curves were distinctly different. At the same sintering temperature the shringkage of Pm was larger than that of PO. Moreover, the turning points of temperature (reflecting transition of the sintering mechanisms) of Pm was higher than that of PO. The microstructure observation showed that sintering at 950 ℃ resulted in mica crystal in glass-ceramics and the best compactness of the sintered blocks of both PO and Pm. Conclusion:Sintering glass powder of smaller particle size at 700-850 ℃ may achieve better sintering compactness.