Sintered Microstructure and Mechanical Properties of High Purity Alumina Ceramics Made by High-Speed Centrifugal Compaction Process

摘要

An alumina powder with a purity of 99.99 and an average particle size of 0.22 mu m, which is dispersed into a slip, and compacted under a centrifugal force of 10-20 kG. The compact can sinter at a rather low temperature of 1503 K in 5.4 ks to give superior mechanical properties with no additive, and retains a homogeneous microstructure in a wide range of sintering conditions up to 1773 K for 5.4 ks. The highest value of the four-point bending strength of this newly developed alumina is 975 MPa, which is about l.3 times . higher than that of the alumina made of the same starting material and sintered to the same porosity and to the same grain size.