Abstract: The incorporation of ceramic phases generally enhances the wear resistance of alloys but often at the expense of their corrosion resistance. In this study, a novel strategy is proposed to synergistically improve both the wear and corrosion resistance of high-speed steel by the construction of mutually encapsulated ceramic phases, enabling effective reduction of potential differences. The advantage of rapid cooling in laser cladding is utilised to form a structure of M₂₃(C, B)₆-type encapsulated of nanoscale M₂(C, N, B)-type, achieved by introducing boron and nitrogen sources. Meanwhile, the composite carbides (M₂₃(C, B)₆-type, M₂(C, N, B)-type and M(C, N, B)-type) formed in the composite coatings, which can achieve a hardness of 1120.1 HV_0.2, a wear rate of (4.46 ± 0.1) × 10^-10 mm³/(mm N), and significantly enhanced tribocorrosion performance. We systematically investigated the influence of ceramic phase type and content, establishing that bulk ceramic phases, unlike fine ceramic phases, enhance performance in materials lacking passivation films. A pathway for improving corrosion resistance in highly wear-resistant materials is paved by the strategy proposed, enabling their application in mission-critical industrial components.

Key words: High speed steel, Carboborides, Carbonitrides, Tribocorrosion, Laser cladding