Thermo-mechanical properties of mullite–zirconia composites derived from reaction sintering of zircon and sillimanite beach sand: Effect of CaO

作     者：P.KUMAR M.NATH A.GHOSH H.S.TRIPATHI 

作者机构：Refractories Division CSIR–Central Glass and Ceramic Research Institute Academy of Scientific and Innovative Research (AcS IR) CSIR–Central Glass & Ceramic Research Institute 

出 版 物：《Transactions of Nonferrous Metals Society of China》 (中国有色金属学报（英文版）)

年 卷 期：2016年第26卷第9期

页      面：2397-2403页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：the Council of Scientific and Industrial Research (CSIR)  Govt. of India  for financial support under project No. ESC-0202 

主　　题：reaction sintering mullite-zirconia composites flexural strength refractory 

摘      要：Mullite–zirconia composites containing 20% zirconia（mass fraction） were prepared by reaction sintering route utilizing Indian coastal zircon flour and sillimanite beach sand. 4%-12% of CaO（mole fraction） with respect to zirconia was used as additive. The effect of additive on densification, microstructure as well as various mechanical and thermo-mechanical properties was studied. Incorporation of CaO reduced the densification temperature of the composites to 1550 ℃ compared to 1600 ℃（for CaO free samples）. CaO formed small amount of liquid phase（calcium aluminosilicate）, which facilitated sintering. Average grain size of the composites decreased up to 4% CaO addition, afterwards grain size increased with further addition of CaO. Samples with 4% CaO exhibited ～225 MPa of flexural strength, ～6 MPa·m^1/2 of fracture toughness and significant improvement in thermal shock resistance. CaO stabilized the tetragonal zirconia phase and thus improved the mechanical properties.