Microstructure and Tribological Properties of In-situ Synthesized TiB_2- TiC /Ni Based Composite Coating by Laser Cladding

摘要

A TiB_2 and TiC particles reinforced Ni based composites coating was prepared on TC4 alloy surface by chemical reaction among Ti, B and C elements using laser cladding technique. Microstructural analysis showed that the sizes of in-situ synthesized TiB_2 and TiC particles ranged within 5～10μm and 1～2μm, respectively, while both the two kinds of particles were uniformly distributed in the clad layer. The measurement of microhardness and wear and friction properties indicated that the microhardness of laser clad layer was HV900～1100, being three times of that of the TC4 alloy; the friction coefficient of the laser clad layer in air and in vacuum (10~(-5) Pa) ranged within 0.2～0.3 and 0.3～0.5, respectively; the wear rate in terms of mass loss was considerably lower than that of the TC4 alloy both in air and in vacuum environment.