Tribology study on TiB₂+WSi₂ composite against WC

Titanium diboride (TiB₂) is one of the potential material for green energy applications such as neutron absorber in high temperature/advanced nuclear reactors, receiver materials for second generation concentrated solar power. We developed the process flow sheet for synthesis and consolidation of various series of TiB₂ based materials in our laboratory. Amongst these, TiB₂+WSi₂ exhibited better sinterability and oxidation resistance properties. In the present work, tribology properties of TiB₂+2.5%WSi₂ composite was studied against WC-Co ball using different normal loads (5, 10 and 20 N) and frequencies (10, 15 Hz) under dry condition. Coefficient of friction (COF) and wear rate was measured at all test conditions. Wear mechanism was analyzed by microstructural characterization. It was found that COF is decreased from 0.46 to 0.36 with increasing load (5 to 20 N) at 15 Hz frequency; whereas at 10 Hz frequency COF is measured a constant average value of 0.49. The specific wear rate measured was minimum at 5 N load and 15 Hz frequency combination and was found to be 2.84×10^-6 mm³/N m. The wear mechanisms identified during reciprocative sliding wear of composite were abrasion and surface tribo-oxidative reactions with delamination from tribo-zone.