Wear resistance of TiB/Ti composite coating fabricated by TIG cladding using Ti-TiB2 cored wire

10 vol%, 20 vol% and 30 vol% TiB whisker (TiBw) reinforced Ti composite coatings, namely B10, B20 and B30, were synthesized by TIG cladding using Ti-TiB2 cored wire. Wear rate and friction coefficient (COF) of the coatings were tested under 5 N, 10 N and 20 N applied loads. The microstructures of the coatings were comprised of pro-eutectic TiBw (B27-type) and eutectic TiBw (hybrid B27/Bf-type) formed due to hypereutectic solidification mechanism. As the applied load rose from 5 N to 20 N, both wear rate and COF decreased regardless of the content of TiB, which was ascribed to the formation of tribo-oxidation layer (TOL). The decreasing percentage of wear rate and COF varied with the TiB content, ranking as B30 (52.9 % and 30.3 %) > B20 (32.4 % and 23.8 %) > B10 (20.2 % and 16.1 %). The difference was attributed to the yield of TOL on wear surface was dictated by the content of pro-eutectic TiBw. The wear debris entrapment by pro-eutectic TiBw was revealed as the formation mechanism of TOL. B10 didn't exhibit enhanced wear resistance due to low ductility, while the load-bearing effect of pro-eutectic TiBw and the protective barrier of TOL contributed to superior wear performance of B20 and B30.