制备工艺对热压Y-α-SiAlON陶瓷微结构及光学性能的影响

采用两步热压烧结(Hot Pressing, HP)方法制备了高致密度的Y-α-SiAlON(Y1410,即m=1.4, n=1.0)陶瓷,研究了升温速率、烧结时间和驻留温度对陶瓷物相组成、微观结构以及光学性能的影响.结果表明:SiAlON陶瓷的相组成不受升温速率的影响,升温速率较快 (20 ℃/min) 时陶瓷的晶粒尺寸相对较小、分布较均齐、透过率相对较高,1.1 mm厚样品最大近红外透过率为50.2%,比升温速率为10 ℃/min的陶瓷高8.0%;烧结时间较短 (1 h) 时陶瓷的晶粒尺寸相对较小,透过率较高,1.1 mm厚样品最大近红外透过率为43.6%,而当烧结时间为2 h时陶瓷中有新相生成,且微结构均匀性较差,其最大透过率比烧结时间为1 h的低8.0%;较低的驻留温度易促进β-SiAlON形成和柱状晶发育,对提高SiAlON陶瓷透光性不利.

Effects of Processing on Microstructure and Optical Properties of Hot Pressed Y-α-SiAlON

Dense Y-α-SiAlON (Y1410 with m=1.4 and n=1.0) was prepared by two-steps hot pressing sintering, and the effects of heating rate, sintering time and holding temperature on phase composition, microstructure and optical properties of sintered samples are studied. The results show that heating rate have no effect on phase composition, but which affect microstructure and optical property, when heating rate is faster (20 ℃/min), microstructure of smaller grain and uniform distribution was observed, and the SiAlON ceramics show higher transmiitance, the maximum transmittance reaches 50.2% for 1.1 mm thickness sample, which is higher 8.0% than sample heating with 10 ℃/min; for the sample with shorter sintering time (1 h), its grain is small and transmittance is higher, the maximum value is 43.6% for 1.1 mm sample, however, for the sample sintered 2 h, new phase was detected, and the grain abnormal develop, which maximum transmittance is by 8.0% higher than that of samples sintered by 1 h; holding temperature at lower temperature during heating contributes to β-SiAlON form and grain abnormality development, which is disadvantage to improving transmittance of SiAlON ceramics.