Densification of Ca-doped alumina nano-powders prepared by a new sol-gel route

Abstract

Ca-doped alumina nano-powders were prepared by a new sol-gel route using Ca-doped polyhydroxoaluminum (PHA) solution under seeding. The nano-powder calcined at 1173K consisted of about 80 nm α-alumina particles and γ-alumina nano-particles. The sintered samples from the nano-powder attained the relative density of >99% with the average grain size of 0.66 μm at 1648K by pressureless sintering. This result implies that the new sol-gel method using Ca-doped PHA solution combined with seeding would be an effective route for producing nano-sized alumina powders, hence leading to the fabrication of fine-grained alumina ceramics at lower sintering temperatures.