Study On The Microstructure And Performance Of Alumina Ceramic

Through doping of different MgO/TiO₂ ratios and adding amount of MgO-TiO₂ additives,mixing by ultrasonic or ball milling process, alumina ceramics were prepared at different sintering temperatures and holding times.The effects of additive content and ratio, the sintering temperature and holding time on alumina ceramic microstructure, bending strength and bulk density were investigated systematically by SEM, Three-point bending test instrument and density measuring device respectively.The results showed that additive amount and MgO/TiO₂ ratio, the sintering temperature and holding time all greatly affected the performance of alumina ceramic. The additive amount and MgO/TiO₂ ratio influenced grain size and morphology evidently. Sintering temperature could significantly change the crystal size and bending strength. Under the certain ratio of additives, the bending strength near the temperature of 1580℃was abnormal.Within holding time range studied,the effect of holding time on the performance of the sample changed with the MgO/TiO₂ ratio of additives .When MgO/TiO₂ ratio was less than 1, the grain size of the sample increased with increase of holding time,but bending strength reduced instead; when its ratio is more than 1, the grain size of the sample changed a little. The impact of mixing process on the microstructure of sample was not very significant,the density of sample prepared by ball milling process was slightly higher than that by ultrasound process.