Microstructure and electrical properties of aluminum oxide-reinforced 3 mol% yttria-stabilized tetragonal zirconia polycrystals/TiSi2 composites by vacuum sintering

3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP)/TiSi2 composites reinforced with aluminum oxide (Al2O3) were synthesized by vacuum sintering. This case investigated the effects of Al2O3 content ranging from 0 to 10 wt.% on the microstructure, mechanical, and electrical properties of 3Y-TP/TiSi2 composites. According to the results, the addition of Al2O3 hindered the densification of the material, resulting in a deterioration in the relative density of composites. On the contrary, the hardness, flexural strength, and average grain size of the conductive phase increased. The maximum value of hardness and flexural strength was 88.70 HRA with 7.5 wt.% Al2O3 and 635.45 MPa with 10 wt.% Al2O3, respectively. In addition, the addition of Al2O3 increases the ratio of grain size between the conductive and insulating phases in composites, leading to a decrease in the percolation threshold and a reduction in resistivity from 4.00 to 1.60 x 10(-3) Omega<middle dot>cm with increasing Al2O3 content. In conclusion, Al2O3 reinforced the comprehensive mechanical properties and optimized the electrical properties of composites by changing the microstructure of the material.