DRY SLIDING FRICTION AND WEAR PROPERTIES OF Ti-TiC COMPOSITE FOAMS PREPARED BY SPARK PLASMA SINTERING AND DISSOLUTION PROCESS

Ti-TiC composite foams were prepared by combining different volume fractions of TiC (0, 5, 10, and 15 vol.%) with NaCl as a space holder (20, 40, and 60 vol.%) by using spark plasma sintering (SPS) and a dissolution process. The sintering properties (relative density, porosity and microhardness), pore structure, friction and wear properties of the prepared foams were systematically studied. The Ti-TiC composite foams sintered at 700 C had an average pore diameter of approximately 230 mu m. The microhardness of the Ti-10 vol.% TiC was significantly higher than that of porous Ti, with values ranging between 360.72 and 490.12 HV0.2 recorded for the composite. The average coefficient of friction (COF) for the Ti-TiC composite foams was measured as 0.12-0.17 using a pin-on-disk tribometer. The lowest COF was obtained for a foam with a volume fraction of added NaCl (V-NaCl) of 40%. The wear rate of the examined foams was inversely related to their porosity, and the addition of TiC particles significantly improved the wear resistance of the porous Ti. The foams with 10 vol.% TiC exhibited the highest wear resistance, with a COF of 0.1349 and a wear rate of 0.65 . 10(-12) m(3) . N-1 . m(-1). The wear mechanism of the Ti-TiC composite foams was a combination of adhesive and abrasive wear.