Abstract
Mullite ceramics containing 20-40 mass% zirconia were rapidly solidified (RS) to obtain amorphous ceramic powder using a Plasma Centrifugal Atomization (PCA) process. The RS and, for comparison, non RS powder were hot-pressed at various temperatures ranging from 1623 to 1823 K Transverse rupture strengths (TRS) of the hot pressed compacts were measured between 293 and 1473 K. The averaged TRS of the RS compacts at room temperature increased with increasing zirconia content However the TRS of the non RS compacts exhibited a peak value at 30 mass% zirconia content. Although the TRS for both materials decreased with increasing temperature, the RS material still had higher values than non RS material at elevated temperature. The improvement in the strength was attributed to a very fine microstructure in the RS compacts produced from amorphous powder.
