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 solidifi-cation 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.

Automated summary

TiB whisker reinforced Ti composite coatings with different TiB content were synthesized by TIG cladding. The wear rate and friction coefficient of the coatings decreased with the increase of applied load, regardless of TiB content. The formation of tribo-oxidation layer (TOL) was responsible for the decrease in wear rate and COF. The yield of TOL was influenced by the content of pro-eutectic TiBw. The wear debris entrapment by pro-eutectic TiBw contributed to the formation of TOL. B20 and B30 exhibited superior wear performance due to the load-bearing effect of pro-eutectic TiBw and the protective barrier of TOL.