Abstract
Alumina-Zirconia (Al2O3-ZrO2) composites especially Zirconia Toughened Alumina (ZTA) shows better mechanical properties over alumina. Al2O3-ZrO2 composites were prepared by powder compaction method varying 3 mol% yttria stabilized zirconia (3Y-ZrO2) content from 0 to 20 vol% using small amount of MgO as sintering aid. The composites were sintered for two hours in air at 1580°C. At this temperature maximum density was achieved 99.31% of theoretical density for composite containing 20 vol% 3Y-ZrO2. Density measurement of sintered composites was carried out using Archimedes’s method. Hardness and fracture toughness measurement was carried out using Vickers indentation. Phase content and t-ZrO2 retention were detected by means of X-ray diffraction (XRD). Microstructure of the composites and grain size of alumina and zirconia was determined by Scanning Electron Microscopic (SEM) analysis. Maximum microhardness (17.46 GPa) was achieved for composite containing 5 vol% ZrO2 and maximum flexural strength (684.32 MPa) and fracture toughness (10.33 MPam0.5) was achieved for composite containing 20 vol% of 3Y-ZrO2. The aim of the present work is to investigate the optimum 3Y-ZrO2 content for obtaining maximum density, microhardness, flexural strength and fracture toughness of Al2O3-ZrO2 composites.
Highlights
Microstructure of the composites and grain size of alumina and zirconia was determined by Scanning Electron Microscopic (SEM) analysis
It is well known that the mechanical properties of alumina ceramics can be considerably increased by the incorporation of fine zirconia particles [6] [7] [8] [9]
An optimum amount of zirconia addition is expected to retain the favorable amount of tetragonal content which can enhance the thermal and mechanical properties of Alumina-Zirconia composites without any grain growth during sintering [18]
Summary
Demand of bioceramics has changed from maintaining an essentially physical function with eliciting a host response, to provide a more integrated interaction with the host This has been accompanied by increasing demand for medical devices to improve the quality of life as well as extended durability. AluminaZirconia composites are an important class of ceramic which exhibit high strength and toughness over alumina due to stress induced phase transformation (tetragonal to monoclinic zirconia) [10] [11] [12]. This phenomenon was first discovered by Clauson in 1976 [6]. Because t-ZrO2 particles are present within the matrix, overstabilization of tetragonal zirconia phase is
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