AZ91D镁合金的均一化前处理与化学镀Ni-P

摘要

Electroless nickel plating on AZ91D substrate with a new and eco-friendly pretreatment process based on tuning an electrochemical homogeneous surface was investigated. The morphology, deposition process, chemical composition and microstructure of Ni−P coating were studied. It is indicated that β phases are selectively removed, producing a microstructural homogeneous surface and the subsequent uniform and compact Zn immersion layer. A defect-free and well adhesive Ni−P coating can be successfully obtained due to its uniform nucleation and growth based on such pretreatment. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests reveal that Ni−P coating could significantly improve the corrosion resistance of AZ91D substrate.%采用新型环保的均一化前处理工艺在AZ91D镁合金表面制备了化学镀Ni−P镀层。研究了前处理过程中AZ91D基体微观形貌、镀层沉积过程、成分和相结构。研究结果表明：基体表面的β相在前处理过程中被选择性去除，表面组织得到均一化，从而获得均匀致密的浸Zn层。Ni−P颗粒均匀形核生长，并最终形成致密的镀层。镀层具有优良的耐腐蚀性能。