Low‐Temperature Sintering of Alumina with Liquid‐Forming Additives

Abstract

Simultaneous application of colloidal processing and liquid‐forming additives to alumina resulted in a sintered density of >99% in 1 h at a temperature as low as 1070°C for a commercial high‐purity alumina powder at a total dopant level of 2 mol%. The additives were 0.9% CuO + 0.9% TiO2+ 0.1% B2O3+ 0.1% MgO. At higher temperatures or after prolonged sintering, the doped alumina ceramic developed a duplex microstructure containing large elongated grains and exhibited a relatively high fracture toughness of ∼ 3.8 MPa · m1/2 as compared to a value of ∼ 2.6 MPa · m1/2 for the undoped alumina. Copyright © 1991, Wiley Blackwell. All rights reserved