Modification of αAI2O3 Platelet/ZrO2 Matrix Interface by Epitaxial Growth of β‐AI2O3 on the α‐AI2O3

Abstract

An epitaxial β‐alumina crystal growth method was used to modify α‐AI2O3 platelet surfaces before inclusion as a reinforcing phase in partially stabilized zirconia (3Y‐TZP). The as‐grown surface phase was Na‐β″‐AI2O3. This was converted to Ca‐β″‐AI2O3 by ion exchange, as the latter is more temperature‐stable at composite sintering temperatures. The conditions of formation, thermal stability, and chemical compatibility of these interfacial phases were examined. α‐AI2O3 platelets with Ca‐β″‐AI2O3 film were incorporated into 3Y‐TZP. The β″‐AI2O3/ZrO2 interface was found to promote platelet debonding and pullout, thus enhancing the α‐AI2O3 platelet/crack interactions during the fracture process.