温度制度对Mg稳定α-sialon陶瓷显微结构、力学与光学性能的影响

Influence of Temperature Scheme on Microstructure,Mechanical and Optical Properties of Mg-stabilized α-sialon Ceramics

本文以m=2n=0.84和1.2为组分,采用热压烧结在1850-1900℃制备出了Mg稳定α-sialon半透明陶瓷。并研究了延长保温时间与升高温度两种方式对Mg稳定α-sialon陶瓷的物相、显微结构、力学和光学性能的影响。XRD结果表明这两种方式均能影响m=2n=0.84组分中β-sialon的含量。相比保温时间的延长,升高温度更易导致晶粒长大,特别是β-sialon的异常长大。这些超大β-sialon有利提高断裂韧性(4.8 MPa·m^(1/2)),但严重恶化光学性能。m=2n=1.2在1900℃烧结1小时所得的样品在波长1.8-4.0μm内透过率超过55%。透过率的提高可主要归结为玻璃相的减少。m=2n=0.84在1850℃保温2小时具有最好的综合性能。

Translucent Mg-stabilized a-sialon ceramics with two compositions,i.e.,m = 2 n = 0. 84 and 1.2,were hot pressed in the range of 1850-1900℃.The influence of holding time and temperature on phase assemblage, microstructure, and mechanical and optical properties of Mg-stabilized α-sialon ceramics was investigated.XRD results show that the content of β-sialon for m = 2 n = 0. 84 was affected by both prolonging holding time and improving temperature. Compared with prolonging holding time,higher temperature could more readily facilitate the growth of grains.In this case, abnormal growth of β-sialon was developed in m = 2 n = 0. 84 at 1900℃ for 1 h, which could improve fracture toughness（4. 8 MPa · m^（1/2）） but seriously deteriorate optical properties.m 2 n= 1. 2 sample sintered at 1900℃ for 1 h exhibits high transmittance of 55%in the range of 1. 8-4. Oμm, which is attributed to the reduced glassy phase.However, the better combination of optical and mechanical properties was obtained in m = 2 n = 0. 84 sample sintered at 1850℃ for 2 h.