激光重熔对喷射电沉积纳米结构镍涂层性能影响研究

采用喷射电沉积方法在45钢基体表面制备了纳米结构镍涂层,研究了激光重熔工艺对涂层性能的影响。用扫描电镜和X射线衍射仪对涂层表面形貌和晶粒尺寸进行分析,并对涂层做表面显微硬度测试和耐腐蚀性试验。结果表明:在优化的工艺参数下,喷射电沉积制备的镍涂层表面比较平整、结合较致密,由平均尺寸为13.7 nm的纳米晶颗粒组成,但涂层中仍存在一些孔隙及其它缺陷;经过激光重熔后,熔融区内的晶粒尺寸明显减小,涂层致密化程度有所提高并使涂层与基体由机械结合变为冶金结合,因此涂层的表面显微硬度和耐腐蚀性能得到明显的提高。

Research on Effect of Laser Remelting on Properties of Jet Electrodeposited Nanocrystalline Nickel Coatings

The nanocrystalline nickel coatings were prepared by jet electrodepositing on the substrate of 0.45% carbon steel,the effects of laser remelting on the properties of coatings were investigated.The surface morphology and the grain size of coating were analyzed by SEM and XRD,and the microhardness and corrosion resistance of coatings were also tested.The results show that the nickel coatings prepared by jet electrodepositing own a fine-grained structure(average grain size is 13.7 nm) with a smooth surface and high density under the optimum processing parameters.However,there are still some pores and other defects.After laser remelting,the grain size of coating is greatly reduced,the density of coating is also improved and the bonding state between the coating and substrate changes from mechanical combination to metallurgical combination.So the laser remelted specimen has higher hardness,better corrosion resistance than ad-deposited coating.