Sintering of a transition alumina: Effects of phase transformation, powdercharacteristics and thermal cycle

The effects of several parameters on the pressureless sintering of a commer cially available transition alumina has been investigated. The capacity of the particles to re-arrange during the phase transformation into the a-alum ina phase has been shown to be a key feature in the densification mechanism . The degree to which the particle re-arrangement can lead to an enhanced d ensification over and above the change in density due to the phase transfor mation from gamma to a phase depends on several parameters. compact density , heating rate and the amount of a-alumina present in the as-supplied raw p owder. The parameters influencing the degree of particle re-arrangement and what directions to take to improve on the above densities and grain sizes are discussed. (C) 1999 Elsevier Science Limited. All rights reserved.