Sintering of AlN ceramics with Y₂O₃:2wt%-Al₂O₃:3wt% of the eutectic point composition

Abstract

We investigated effects of sintering additives having the eutectic point composition (1760°C) in the phase diagram of the Y₂O₃-Al₂O₃ system on sintering process of AlN ceramics. Two kinds of the sintering additives were added to AlN powder. One of these additives was Y₂O₃:Al₂O₃=2:3 wt%, another was Y₂O₃:Al₂O₃=4:6 wt%. Samples of AlN with the additives were sintered at temperatures of 1600∼1750°C for 0.5∼5h in N₂ atmosphere. Shrinkage, weight loss, density and XRD measurements and SEM observation were performed on the sintered samples. From the shrinkage and density measurements, it was found that densification of the samples drastically developed at greater than the temperature of 1750°C. The densification depends upon the eutectic point temperature.