Hot Hardness Behavior of Yttrium Sialon Ceramics

Abstract
The hot hardness of polycrystalline single‐phase α‐ or β‐ sialon ceramics declines with increasing temperature, but the measured Vickers hardness (HV1) at 1100°C is still about 1550 and 1300 for the α‐sialon and the low‐substituted β‐sialon materials, respectively. The hardness of ‘composite’β‐ or α‐β‐sialon ceramics containing a high volume fraction of glassy phase is lower at all temperatures and drops significantly above about 900°C.