Microstructures and intrinsic lubricity of in situ Ti3SiC2-TiSi2-TiC MAX phase composite fabricated by reactive spark plasma sintering (SPS)

MAX phase composite Ti3SiC2-TiSi2-TiC based on the Tin+1SiCn system was synthesized by spark plasma sintering (SPS) under vacuum sintering conditions. The microstructural evolution upon synthesis and Vickers indentation contact damage were characterized using scanning electron microscopy (SEM) and optical microscopy (OM). Tribological behaviour of the SPSed MAX phase composite was investigated under dry sliding ambient conditions for evidence of intrinsic lubricity as well as to understand the influence of second phase TiC particles on the wear behaviour of this composite system. Further, the underlying wear mechanisms was elucidated via detailed analyses of the worn surfaces using Raman spectroscopy, SEM-EDS and transmission electron microscopy (TEM). Exhaustive analyses of the worn surface revealed evidence of solid lubrication. Transition in friction and wear is attributed to change in wear mechanism from tribo-oxidative to deformation-induced wear due to the disruption of the tribofilm architecture.