Effects of h-BN content and heat treatment temperature on the tribological behavior and toughness of laser-clad Mo2FeB2/WC/h-BN coatings.

In this study, h-BN-modified Mo 2 FeB 2 /WC composite coatings were fabricated via laser cladding. The Mo 2 FeB 2 /WC/10 wt% h-BN composite coatings were heat-treated at 400, 600, and 800 °C. The microstructure, microhardness, tribological properties, residual stress, fracture toughness and fracture morphology of the coatings were investigated. The results showed that h-BN addition combined with heat treatment promoted the distribution of elements and finer microstructure. The Mo 2 FeB 2 /WC/10 wt% h-BN coating heat-treated at 600 °C showed the highest microhardness (1416.8 HV 0.5) among the prepared coatings. The pristine and 600 °C heat-treated Mo 2 FeB 2 /WC/10 wt% h-BN coating showed excellent wear rates (1.97 and 1.84 × 10−5 mm3/Nm, respectively). The composite coatings modified with h-BN exhibited an abrasive wear mechanism after heat treatment. As the h-BN content and heat treatment temperature increased, there was a notable decrease in residual stress. Specifically, the coating subjected to heat treatment at 800 °C demonstrated the lowest residual tensile stress recorded at 168 MPa. Conversely, when heat-treated at 600 °C, the coating exhibited an optimal fracture toughness of 14.96 MPa⋅m1/2, with fracture behavior consistent with typical brittle fracture characteristics. [ABSTRACT FROM AUTHOR]