The Effect of Mullite Addition on Wear Properties of SiO2 Doped ZrO2 Ceramics

Mullite (3Al2O3.2SiO2) and 10 mol% silica added zirconia (10 mol% SiO2 - 90 mol% ZrO2) ceramic powders were synthesized by conventional ceramic processing route. The mixtures were prepared by mechanical alloying method using zirconia ball mill in acetone environment. To synthesize mullite, Al2O3 and SiO2 powders mixture was prepared with stoichiometric proportions and fired it in the air at 1600 oC for 3 h. And the silica added zirconia composites were fired at 1300 oC for 2 h. Thus, silica - zirconia and mullite composite phases were obtained and milling and sieving processes were carried out. Then, mullite-free and 10% by weight mullite reinforced silicon oxide added zirconia mixtures were prepared by powder metallurgy method. The powders were compacted by uniaxial pressing. The formed samples were sintered in a high temperature furnace in air conditions for 1 and 5 h at 1500 and 1600 oC sintering temperatures. Finally, microstructure examinations of the composites with SEM, phase analysis with XRD, hardness, three-point bending and wear tests were performed. In addition, the results of water absorption, porosity and density from physical properties and the effect of mullite additive on the mechanical and especially wear properties of this mixture were investigated.