Evaluation of sintering stresses of an Al 2O 3 powder with a self-loading apparatus

Abstract

The sintering stress of an Al 2O 3 powder, σ s, is evaluated from an equation σ s = F s/ ρS a, where F s is the uniaxial tensile force necessary to just stop the sintering contraction, ρ is the relative density, and S a is the cross-sectional area. During densification, σ s increases to the maximum at a relative density of 85%, and then abruptly decreases. The variation of σ s in the intermediate sintering stage suggests a simple cubic packing of particles. Densification in the final sintering stage is explained by shrinkage of the pores at the corners where four tetrakaidecahedra meet. The present surface tensions of the Al 2O 3 powder evaluated from the σ s roughly equal a reported value.