中文摘要：

为了提高奥氏体不锈钢的高温耐磨性能，采用中空激光熔覆技术在1Cr18Ni9Ti奥氏体不锈钢表面制备出以（Cr，Fe）7C3为增强相γ-（Ni，Fe）固溶体为基体的高温耐磨复合涂层。分别在室温、300℃和600℃时测试了涂层和不锈钢基体的干滑动磨损性能，并讨论了其磨损机理。结果表明，涂层的耐磨性能明显优于不锈钢基体。室温时，不锈钢的磨损机理为粘着磨损，涂层为磨粒磨损；300℃时，不锈钢的磨损机理为粘着磨损和磨粒磨损，涂层为粘着磨损；600℃时，不锈钢磨损表面出现脆性断裂、塑性变形及严重氧化，涂层表面发生轻微的磨粒磨损和粘着磨损。由于摩擦抛光作用和均匀连续转移膜的形成，涂层在600℃时的耐磨性能高于300℃。

英文摘要：

Aiming at improving high-temperature wear resistance of austenitic stainless steel, a wear resistant composite coating reinforced with hard （Cr, Fe）TCa carbide and toughened by ductile 7- （Ni, Fe） solid solution matrix is fabricated by a novel central hollow laser cladding technique. Sliding wear tests of the composite coating and substrate are conducted at ambient temperature, 300 ℃ and 600℃, respectively, and the corresponding wear mechanisms are discussed. Results indicate that the composite coating exhibits superior wear resistance than substrate either at ambient or high temperatures. At ambient temperature, the wear mechanism of the substrate is dominated by adhesive wear while the coating shows abrasive. At 300 ℃ , the substrate＇s wear mechanism is the combination of adhesive and abrasive wear while the coating＇s is abrasive wear. As temperature attains 600 ℃, brittle fracture, plastic deformation and severe oxidation are discovered on the substate＇s worn surface, while the coating exhibits mild adhesive and abrasive wear. The coating shows better sliding wear resistance at 600 ℃ than that at 300℃ owing to polishing effect and formation of lubricative continuous transfer films, which implies that it has large potential in higher temperatures.