Toughening of alumina/zirconia ceramic composites with silver particles

Al2O3/ZrO2/Ag composites were obtained by intense attrition milling of silver and alumina powders with TZP balls. The characteristics of mixtures and the mechanical properties of sintered samples were investigated. Milling in acetone for 7 h results in a homogeneous submicron mixture. Ag composites (10 vol.%) CIPed at 300 MPa contain 8.1 vol.% tetragonal zirconia and 8.0 vol.% silver after sintering in air for 2 h at 1550 °C. Fracture toughness and bending strength as high as 5.44 MPa m and 586 MPa were obtained (645 MPa by post-HIPing). The incorporation of more silver (20 vol.%) is detrimental to microstructure quality and strength, but fracture toughness remains high thanks to crack bridging effects developed by ductile metallic inclusions.