镍基金属陶瓷涂层在人工海水中的摩擦学性能

Tribological Properties of Ni-based Cermet Coatings in Artificial Seawater

目的探讨镍基金属陶瓷涂层在海水中的耐腐蚀磨损性能。方法采用激光熔覆技术在45钢表面制备了1.1 mm厚的镍基金属陶瓷涂层。采用电化学测试系统,对比分析了涂层的耐蚀性。采用往复式摩擦磨损试验机,测量了涂层在干摩擦及海水环境下的摩擦系数。采用扫描电镜等手段分析了涂层和磨痕的表面形貌。结果镍基金属陶瓷涂层的表面硬度约为基体的3倍,且硬度较均匀。在结合区开始,硬度剧烈下降,直至降为基体硬度。在3.5%Na Cl溶液中,镍基金属陶瓷涂层的腐蚀倾向低于316L不锈钢及316L堆焊层,而腐蚀速率介于两者之间。干摩擦条件下,镍基金属陶瓷涂层明显降低了基体的摩擦系数(从0.58降低至0.49)和磨损量(降低了50%)。与干摩擦实验相比,人工海水明显降低了镍基金属陶瓷涂层的摩擦系数(从0.49降低至0.37)和磨损量(降低了40%)。结论由于具有良好的耐蚀性和较高的硬度,镍基金属陶瓷涂层在人工海水中表现出了良好的耐磨耐蚀性能。磨损过程中,人工海水的冷却、润滑作用和其中盐类的隔离作用,有效改善了摩擦界面的接触状态,提高了镍基金属陶瓷涂层的耐磨性。

The work aims to study corrosion wear resistance of Ni-based cermet in seawater. 1.1 mm thick Ni-based cermet coatings were prepared by adopting laser cladding technology on 45# steel. Corrosion resistance of the coatings was contrastively analyzed with an electrochemical test system. Friction coefficient of the coatings was measured under conditions of dry friction and seawater environment with a reciprocating friction-abrasion testing machine. Surface morphology of the coatings and grinding cracks was analyzed with SEM, etc. Surface hardness of the Ni-based cermet coatings was uniform and nearly 3 times of the substrate. The hardness decreased dramatically from bond zone until it reduced to hardness of the substrate. In 3.5%Na Cl solution, corrosion tendency of Ni-based cermet coatings was lower than that of 316 L stainless steel and 316 L surfacing layer, while corrosion rate of the Ni-based cermet coatings was between that of the two. The Ni-based cermet coatings significantly reduced friction coefficient（from 0.58 to 0.49） and wear loss（decreased by 50%） of the substrate under the condition of dry friction. Compared with dry friction experiment, the artificial seawater clearly reduced friction coefficient（from 0.49 to 0.37） and wear loss（decreased by 40%） of the Ni-based cermet coatings. The Ni-based cermet coatings exhibit good corrosion wear resistance in artificial seawater due to excellent corrosion resistance and high hardness. During wear process, contact status of friction interface is effectively improved, and wear resistance of the Ni-based cermet coatings is enhanced under cooling and lubrication effect of artificial seawater, and isolation effect of salts in artificial seawater.