Microstructure and properties of alumina ceramics prepared from submicrometer alumina powder with MgO–ZrO2 coated on alumina grain surface

Abstract

For preparing alumina ceramic prosthetic implants with dense microstructure and good mechanical properties, a combined technique of ball–milling, air–blowing, chemical precipitation and calcinations was explored and used to prepare submicrometer alumina powder with MgO–ZrO2 coated on alumina grain surface, and then alumina ceramics were prepared by sintering alumina green bodies made by cold isostatic pressing. Because of the well distribution of ZrO2 on the surface of alumina grains, the alumina ceramics obtain dense microstructure and excellent mechanical properties. With the increase of molar ratio between ZrO2 and alumina powder in raw material from 0.02 to 0.08, the alumina ceramics get almost fully dense microstructure and its flexural strength increases from 589 to 637 MPa, its fracture toughness increases from 5.62 to 6.16 MPa m1/2 and its Vickers hardness increases from 17.3 to 17.7 GPa. The alumina ceramics prepared in this work are promising prosthetic implants materials with excellent mechanical properties.