Sintering behavior and mechanical properties of hydroxyapatite-zirconia composites

摘要

The elaboration of composite materials has been considered one possibility to improve mechanical properties of bioactive phases based on hydroxyapatite used for medical implants. Ceramic and polymeric materials have been tested as the other phase. The aim of this study is to evaluate the sintering behavior and the mechanical properties (compressive strength, modulus of resiliency and microhardness) of hydroxyapatite-zirconia (ZH) composites prepared by precipitation method. Powders of hydroxyapatite-zirconia (ZH) cmposites, with 40 vol percent of zirconia content, and pure hydroxyapatite (HA) as well as pure ZrO_2 - CaO (ZO) were sintered at 900, 1100 and 1200 deg C in air at a pressure of 700 MPa for 3 hours, using uniaxial pressing. The products obtained at 1100 and 1200 deg C are dense, with density values over 91percent of the theoretical ones. Experimental results indicated that the sinterization process can be described as admitting a bi-modal structure for ZH composites consisting of a sphere of ZO embedded into a matrix of HA. In this structure the matrix is consider to sinter faster. Intermediate values (between those of pure phases of HA and ZO) of compressive strength and modulus of resiliency were found for ZH composites, suggesting that these composites have potential applications as implant materials.