High temperature wear characteristics of TiC composite coatings formed by laser cladding with CNT additives

High temperature wear properties of titanium carbide (TiC) composite coatings fabricated by laser cladding with titanium powder and varied percentages of carbon nano-tube (CNT) powders on titanium substrates have been tested by pin-on-disk wear under dry sliding conditions. The results reveal that TiC composite coatings fabricated with proper addition of CNT give promising high temperature wear resistance which is ten times higher than that of the titanium substrate. The high temperature wear behavior and friction coefficient of the titanium substrate and the composite coatings were investigated. It was found that the wear behavior of the dominant wear mechanism of the TiC composite coatings is adhesive wear and oxidation, whereas the Ti substrate exhibits abrasive wear, adhesive wear, serious plastic deformation, and oxidation at high temperature. The improvement of the wear resistance is believed to be attributed to the reinforcement phase of TiC which can also provide high hardness according to the microstructure observation of the composite coatings by SEM, EDX and microhardness measurements.