Hardness and fracture toughness of monolithic and composite ceramics

U ovom radu ispitivano je hoće li se dodavanjem cirkonij oksida smanjiti krhkost aluminij oksidne keramike, te kako će se zbog toga ponašati njena tvrdoća. Ispitivanje tvrdoće i lomne žilavosti provedeno je na četiri uzorka s različitim udjelom cirkonij oksida. Uzorak 1 je monolitna keramika u obliku čistog aluminij oksida (100 % Al2O3) dok uzorci 2, 3 i 4 predstavljaju ZTA kompozitnu keramiku s udjelima ojačala koji redom iznose 1 % ZrO2 (99 % Al2O3), 5 % ZrO2 (95 % Al2O3) i 10 % ZrO2 (90 % Al2O3). Na temelju izmjerenih vrijednosti tvrdoća i lomne žilavosti odabran je optimalni udjel cirkonij oksida u ZTA keramici.In this paper, it was analysed whether the addition of zirconium oxide would reduce the brittleness of aluminum oxide ceramics, and how it would affect the hardness. The hardness and fracture toughness test was performed on four samples with different zirconium oxide percentage. Sample 1 is a monolithic ceramic in the form of pure aluminum oxide (100% Al2O3) while samples 2, 3 and 4 represent ZTA composite ceramics with reinforcement proportions of 1% ZrO2 (99% Al2O3), 5% ZrO2 (95% Al2O3) and 10% ZrO2 (90% Al2O3). Based on the measured values of hardness and fracture toughness, the optimal content of zirconium oxide in ZTA ceramics was selected