多步电沉积纳米金属陶瓷复合层工艺及性能

Process and Properties of Nano-cermet Composite Coating by Multistep Electrodeposition

摘要:

为提高纳米金属陶瓷复合沉积层性能，采用多步电沉积工艺在合金钢表面制备 Ni-TiN-GO(氧化石墨烯)复合沉积层，分析其组织结构、成分、显微硬度、耐磨性和耐蚀性，确定最适宜的多步电沉积工艺，在此基础上对沉积层进行后处理， 探究后处理对沉积层耐蚀性的影响。结果表明:三步电沉积工艺获得的沉积层组织性能最好，沉积层与基体结合紧密，厚度为 24.6μm，表面均匀致密，晶粒尺寸约为 20nm，晶粒表现为(111)和(200)晶面双择优取向;沉积层显微硬度为 2249.44HV， 摩擦系数为 0.8，磨损机制以微弱磨粒磨损为主;Tafel 极化曲线测试表明，三步电沉积层自腐蚀电位为-0.677V，自腐蚀电流 密度为 1.71×10-5A·cm-2，96h 盐雾试验后，沉积层表面无明显变化;后处理后，三步电沉积层自腐蚀电位正移 60mV，自腐蚀电流密度下降一个数量级。

Abstract:

In order to improve the properties of nano-cermet composite electrodeposited coatings, Ni-TiN-GO (Graphene Oxide) composite electrodeposited coatings were prepared on the surface of alloy steel by multi-step electrodeposition process. Its microstructure, composition, microhardness, wear resistance and corrosion resistance were characterized and analyzed, and determine the most suitable multi-step electrodeposition process. On this basis, the coating was post-treatment, the effect of post-treatment on the corrosion resistance of the coating was studied. The results show that the microstructure and properties of the coating obtained by three-step electrodeposition are the best, good bonding with the substrate and the thickness is 24.6 μm, the coating obtained by three-step electrodeposition has uniform and dense surface, and the grain size is about 20nm, and the grains show double preferred orientation of (111) and (200) planes. The microhardness of the electrodeposited coating is 2249.44HV, and the friction coefficient is 0.8. the wear mechanism is mainly weak abrasive wear. The results of Tafel polarization curve test showed that the corrosion potential of the three-step electrodeposited coating is -0.677V, and the self-corrosion current density is 1.71×10-5A·cm-2, After 96h salt spray test, the morphology of the coating did not change obviously. After post-treatment, the self-corrosion potential of the three-step electrodeposited coating shifted positively to 60mV, and the self-corrosion current density decreased by an order of magnitude.