激光熔覆Al-Ni-TiC-CeO2复合涂层的组织与耐腐蚀磨损性能

采用激光熔覆技术在S355海洋钢表面制备Al-Ni-TiC-CeO2熔覆涂层,通过SEM、EDS、XRD、显微硬度计等手段分析其表面-界面形貌、化学元素分布、物相组成及显微硬度,并研究其在3.5%(质量分数)NaCl溶液中耐腐蚀磨损与应力腐蚀开裂(stress corrosion cracking,SCC)等性能。结果表明:熔覆涂层主要由增强相TiC和连续相AlNi3,AlFe3组成,表面较为平整,无明显裂纹,稀释率为5%。涂层表面显微硬度达到809.3HV0.2,为基体的2.3倍。基体中交互作用主要以腐蚀加速磨损为主,而涂层中交互作用则以磨损加速腐蚀为主。基体材料与涂层的SCC敏感性分别为35.01%和17.69%,表明涂层能够明显抑制应力腐蚀开裂。

Microstructure and corrosion-wear resistance of laser cladding Al-Ni-TiC-CeO2 composite coatings

Al-Ni-TiC-CeO 2 composite coatings were prepared by laser cladding technique on S355 offshore steel.The surface-interface morphologies,chemical element distribution,phase compositions,microhardness of the as-prepared coatings were analyzed by means of scanning electron microscope(SEM),energy dispersive X-ray spectrometer(EDS),X-ray diffractometer(XRD)and microhardness tester.Also,the corrosive wear resistance and stress corrosion cracking(SCC)of the coatings in 3.5%(mass fraction)NaCl solution were studied.The results show that the coating is mainly composed of TiC and AlNi 3 phases as well as AlFe 3 phase.The surface of the coating is relatively smooth,there is no obvious crack,and the dilution rate is 5%.The surface hardness of the coating is 809.3HV 0.2,which is 2.3 times as high as the substrate.The interaction is mainly corrosion accelerating abrasion in the substrate,while it is wear accelerating corrosion in the coating.The SCC susceptibility of the substrate and coating are 35.01%and 17.69%respectively,which indicates that the coating can inhibit the SCC obviously.