Tribological properties of pressureless sintered alumina matrix ceramic materials improved by diopside

In this paper, diopside was introduced into alumina as a sintering aid and fine structural alumina matrix ceramic materials were fabricated by the technology of pressureless sintering. The relative density, hardness and fracture toughness of the diopside-reinforced composites were investigated. Tribological tests were carried out at a rotation speed ranged from 40 to 160 rpm and in a normal load ranged from 50 to 200 N. SEM technique was employed to observe worn surfaces of the test specimens and wear mechanisms were simultaneously discussed. Analysis of the experimental data and observations on worn surfaces revealed that the improvement in wear resistance of composites may be attributed mainly to the stronger toughening effect due to addition of diopside in alumina matrix.