Evaluation of hardness and wear behavior of laser cladding zirconia-alumina-titania ceramic top coating on pure Ti6Al4V

Abstract The paper deals with the synthesis and evaluation of hardness and wear-resistant properties of the ceramic composite (zirconia-alumina-titania) coating on commercially available pure Ti6Al4V (cpTi) substrate. The coating is produced by laser irradiation of the pre-mixed pre-placed nanopowders of Ti6Al4V and yttria-stabilized ZrO2(YSZ). The influence of the magnitude of incident laser energy on the cross-sectional microstructure change, hardness, coefficient of friction has been discussed. The X-ray diffraction test of the laser cladding samples shows the in-situ formation of ceramic particles such as titania and alumina apart from zirconia. The zirconia exists in the solution of titania and alumina in the matrix of Ti6Al4V. The hardness of the coating is found to be 3 times higher than the substrate. The coefficient of friction of the metal matrix reinforced with the ceramic composite coating is significantly lower than the substrate material. The existence of both monoclinic and tetragonal structure of zirconia attributes not only the toughness but also thermal stability to the ceramic coating at a higher temperature.