Wear Resistance of B4C-TiB2 Ceramic Composite

Abstract

The effects of microstructure and mechanical properties on the wear resistance of B4C-TiB2 ceramic composite were studied. The composite was hot pressed from a B4C-TiO2 precursor at a temperature range of 1800 and 1850 °C. Both the relative density and amount of TiB2 secondary phase of the B4C-TiB2 composite increased with the amount of TiO2 sintering additive in B4C-TiO2 precursor. The hardness of the composite increased with a secondary phase portion up to 29.8 vol.% TiB2. However, the positive effect of TiB2 secondary phase on the fracture toughness of B4C-TiB2 composite was measured in the complete experimental range, with the highest average attained value of 7.51 MPa·m1/2. The wear resistance of B4C-TiB2 composite increased with both the hardness and fracture toughness. The best wear resistance was achieved with the composite with a higher hardness value of 29.74 GPa. This sample consisted of 29.8 vol.% TiB2 secondary phase and reached a fracture toughness value of 6.91 MPa·m1/2. The fracture-induced mechanical wear of B4C-TiB2 composite was the main wear mechanism during the pin-on-disc wear test. Transgranular fracture with pullout of the surface and micro-crack formation in the direction perpendicular to the wear direction was observed on the worn surfaces