Preparation and enhanced wear resistance of HVAF-sprayed Fe-TiB2 cermet coating reinforced by carbon nanotubes

Carbon nanotubes (CNTs) with superior properties were introduced for the first time into Fe-TiB2 cermet coating to strengthen its wear resistance. Initially, composite feedstock in which every powder was not only highly spherical and dense but also contained uniform CNTs and TiB2 were successfully prepared. Then, Fe-based metallic and Fe-TiB2 cermet coating with or without CNTs were deposited via high velocity air fuel (HVAF) to mainly investigate the effect of CNT addition on the microstructure and wear behavior of coatings. It shows that, with incorporation of 2.5 vol% CNTs, the coating microstructure became denser and the microhardness and fracture toughness of Fe-TiB2 cermet coating obtain increases of 32% and 44% (or 61%). As a result, the improved tribological properties, the lowest porosity and fewest wear crack contribute to its best wear resistance with specific wear rate of 2.47 × 10−6 mm3/N·m. Oxidative and mild abrasive wears rather than severe adhesive wear were the dominant wear mechanism of coating reinforced by CNTs. [Display omitted] •Spherical and dense composite feedstock with uniform CNT and TiB2 were prepared.•Adding CNTs achieved significant increase in microhardness and fracture toughness.•Obvious enhancement in tribological properties was obtained via doping CNT.