Sintering and mechanical properties of hydroxyapatite-zirconia composite ceramics

Hydroxyapatite has weak mechanical properties, and therefore, despite its excellent biological compatibility, is only used as implant substitutes of not-load-bearing body parts such as inner ear bone, and as filler material. This study aimed at improving the mechanical properties of hydroxyapatite by TZP addition. Composites of HAP-TZP that contain 10 and 20% TZP were prepared via slip casting method and compared with a control sample not involving TZP. Preformed samples were sintered without pressure at 1100, 1200 and 1300°C for 1 hr. Following sintering mechanical properties like density, hardness, bending strength, and fracture toughness were determined. It was observed that ZrO₂ addition over 10%, and increasing reaction temperatures lead to deterioration in the mechanical properties of the samples.