Microstructural evolution and infrared radiation property of Ca2+-Cr3+ doped LaAlO3 in the presence of SiO2

The effects of SiO2 content on the phase and microstructures of high emissivity ceramic material, Ca2+-Cr3+ doped LaAlO3 (LCCA) was investigated. The addition of SiO2 led to the formation of silicate Ca2La8(SiO4)6, Ca2SiO4 and Al-Si-Ca-La-O glass phase in the LCCA pellets. With the increase of SiO2, doped LaAlO3 phase decomposed gradually and nearly disappeared at 20 wt% SiO2. Besides, the infrared radiation property attenuated with the content of SiO2. The emissivity was decreased from 0.93 in the absence of SiO2 to 0.88 in the presence of 20 wt% SiO2. It indicates that SiO2 content should be carefully controlled when SiO2 or SiO2-containing sol is used a high temperature binder.