为了提升钢制结构表面的耐磨耐蚀性能,采用激光熔覆技术在N80基体上制备了CoCrMnNiMox(x=0.1,0.2,0.3,0.4)系4种不同成分的高熵合金涂层,研究了Mo含量变化对高熵合金组织与耐磨耐蚀性的影响。结果表明:CoCrMnNiMox涂层结构为单一FCC相,随Mo含量的增加,涂层硬度提升,CoCrMnNiMo0.4平均维氏硬度高达628 HV,相较于N80基体硬度(165 HV)提升了3.8倍;摩擦系数先降低后增加,Mo含量为0.3时达到最低(0.38),相比于N80基体降低了0.40;熔覆层磨损机理由黏着磨损变为磨粒磨损,耐磨抗力增加。熔覆层动态腐蚀与静态腐蚀皆在Mo0.3时达到最优。与基体相比,Mo含量为0.3时的动态腐蚀电位上升了0.20 V,腐蚀电流密度下降了1个数量级。但由于磨损对腐蚀的促进作用,熔覆层耐蚀性较静态腐蚀相比均有较大程度降低。腐蚀磨损耦合测试结果表明,随Mo含量的增加,电位先逐渐增加后又降低,Mo含量为0.3时电位达到最高(-0.28 V),摩擦状态下耐蚀性能最好,相比于N80基体(-0.50 V)提升了0.22 V,很好地改善了基体表面的耐磨蚀性能。试样腐蚀下的摩擦系数先增加后减小,除Mo0.2摩擦系数较高,其余成分在稳定磨合阶段的摩擦系数均较低,腐蚀条件下耐磨性能相对较好。
In order to increase the wear and corrosion resistance of the surface of the steel structures, four kinds of CoCrMnNiMox (x=0.1, 0.2, 0.3, 0.4) high entropy alloy (HEA) coatings with different compositions were prepared on N80 steel substrate by laser cladding. The effect of Mo content on microstructure, wear resistance and corrosion resistance of HEA coating was studied. Results showed that the CoCrMnNiMox coating structure was a single FCC phase. With the increase of Mo content, the coating hardness increased. The average Vickers hardness of the CoCrMnNiMo0.4 HEA coating was up to 628 HV, which was 3.8 times higher than that of N80 steel substrate (165 HV). The friction coefficient decreased first and then increased, reaching the lowest (0.38) at Mo content of 0.3, which reduced by 0.40 compared to that of N80 substrate. The wear mechanism of clad layer changed from adhesive wear to abrasive wear and the wear resistance increased. The dynamic corrosion and static corrosion of clad layer reached the optimum at Mo content of 0.3. Compared with the substrate, the dynamic corrosion potential increased by 0.2 V at Mo content of 0.3, and the corrosion current density decreased by one order of magnitude. However, the corrosion resistance of the clad layer was greatly reduced compared with the static corrosion due to the promoting effect of wear on corrosion. The corrosion wear coupling test results showed that with the increase of Mo content, the potential first gradually increased and then decreased. The potential reached the highest (-0.28 V) at Mo content of 0.3. The corrosion resistance under friction condition was the best, which was 0.22 V higher than that of N80 substrate (-0.50 V). The wear and corrosion resistance of the substrate surface were well improved. The friction coefficient of the sample under corrosion increased first and then decreased. Except for the high friction coefficient at Mo content of 0.2, the friction coefficient of the other samples was low in the stable run-in stage, and the wear resistance under corrosion condition was relatively good.
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