In this study, a boride cladding layer with Mo₂FeB₂ hard phase was prepared on the GCr15 steel via plasma cladding. The phase composition, microstructure, thermal fatigue resistance, microhardness, and wear resistance of the boride cladding layer were investigated. The results revealed that the hard phases in the boride cladding layer were Mo₂FeB₂ and (Cr,Fe)₂₃(C,B)₆, while the binder phase consisted of α-Fe martensite. When the thermal fatigue times increased, the indentation crack length extended in a quadratic pattern, and the crack propagation rate increased. Crack propagation in the cladding layer occurred via both transgranular and intergranular modes. When the thermal fatigue temperature was below 600 °C, the cladding layer exhibited good thermal stability, and a reliable metallurgical bond was formed between the cladding layer and the GCr15 steel substrate. The microhardness of the cladding layer reached 1022.1 HV_0.5, approximately 2.6 times that of the GCr15 steel. The mass loss of the cladding layer increased with the increase in wear load and wear time. The wear of the cladding layer was mainly three-body abrasion wear, resulting from brittle spalling of the hard phase on the worn surface. This study demonstrates the potential of Mo₂FeB₂-based cladding layers for extending the service life of high-value industrial components.

Co-Cu-Ti composite coatings were fabricated on Ti6Al4V substrates by laser cladding. The Criteria Importance Through Intercriteria Correlation–Technique for Order Preference by Similarity to Ideal Solution methodology was employed to determine the optimal parameters. The effect of varying the scanning speed, a critical parameter, was investigated to evaluate its influence on the coating’s microstructure and performance. The phase composition of the coatings comprises Co-Ti phases and Cu-Ti phases. The microhardness and wear resistance of the coatings initially increase as the scanning speed rises, reaching a peak before subsequently declining. The predominant wear mechanisms of the coatings are abrasive wear, with minor contributions from adhesive wear and fatigue wear. The wear resistance of the coating is superior to that of the TC4 substrate, primarily due to the synergistic enhancement from the strengthening effect of the Co-Ti phase and the lubricating effect of the Cu-Ti phase. The composite coatings fabricated at a scanning speed of 3 mm/s exhibited superior properties. Specifically, the microhardness measures 788 HV_0.2, the coefficient of friction is approximately 0.57, and the wear cross-sectional area is 3.57 × 10⁻⁹ mm². At this speed, these two effects achieve an optimal balance, making it the best process parameter for wear resistance.