Evaluation of residual stress and corrosion behaviour of electroless plated Ni-P/Ni-Mo-P coatings

化学沉积Ni-P/Ni-Mo-P镀层的残余应力和腐蚀行为评价（英文）

Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating.The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis,and the corrosion behaviour of the coatings in10%HCl solution was evaluated by electrochemical methods,to establish the correlation between the residual stresses and corrosion behaviour of the coatings.The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of241and206MPa respectively,while the single Ni-Mo-P coating exhibited a residual tensile stress of257MPa.The residual compressive stress impeded the growth of the pre-existing porosity in the coatings,protecting the integrity of the coating.The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating.In addition,the stress states affect the corrosive form of coatings.

通过化学沉积法制备Ni-P、Ni-Mo-P单镀层以及与其成分相同的Ni-P/Ni-Mo-P双镀层。采用纳米压痕法和AFM分析测量镀层表面和截面的残余应力,并用电化学法评估镀层在10%HCl溶液中的腐蚀行为,以获得镀层残余应力与腐蚀行为之间的关系。结果表明:Ni-P单镀层和Ni-P/Ni-Mo-P双镀层表现为残余压应力,分别为241和206 MPa;Ni-Mo-P单镀层呈现出257 MPa的残余拉应力。残余压应力阻止镀层中孔洞的生长,保护镀层的完整性。Ni-P/Ni-Mo-P双镀层比它们的单镀层具有更好的耐蚀性。此外,镀层的应力状态影响其腐蚀形式。