Effect of Different Molar Ratios of MgO/Al203 on the Thermal Shock Behavior and Microstructure of MgO-Al203-4 mol % SiO2 Composite Ceramics
In this paper, MgO and Al2O3 were used as the main raw materials and SiO2 was used as the doping agent, composite ceramics were sintered at 1450 ℃ and 1550℃.The sintered samples were characterized by phase analysis and thermal cycling times.Moreover,field emission scanning electron microscope was also employed to study microstructure of the sintered samples before and after thermal shock.Effect of the different molar ratios of MgO/Al2O3 on the microstructure and thermal shock resistance of composite ceramics with doping 4 mol % SiO2 were investigated The results showed that the optimum molar ratio of MgO/Al2O3 is equal to 2/1, the phase composition of the sintered samples contain magnesium aluminate spinel and forsterite phase in addition to periclase phase at the moment, and the sample possess better thermal shock resistance, the number of thermal shock could approach twenty times until the sample was broken.The fine grain and polycrystalline structure was obvious by observing the microstructure of the sample which the molar ratio of MgO/Al2O3 was equal to 2/1, Magnesium aluminate spinel was observed with mesh structure connected to each other.Furthermore, the cracks appeared the phenomenon of deflection and bifurcation after thermal shock, the main crack propagation was restricted and more fracture energy was consumed.The thermal shock resistance of composite ceramics could be greatly improved.
magnesia composite ceramics microstructure thermal shock resistance
FENG Dong LUO Xudong ZHANG Guodong XIE Zhipeng
School of High Temperature Materials and Magnesium Resource Engineering,Liaoning University of Scien School of High Temperature Materials and Magnesium Resource Engineering,Liaoning University of Scien Key Laboratory of New Ceramics and Fine Processing,School of Materials Science and Engineering,Tsing
国际会议
西安
英文
1-5
2016-09-20（万方平台首次上网日期，不代表论文的发表时间）