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在AZ91D镁合金上直接化学镀Ni-P和Ni-W-P镀层,并利用扫描电子显微镜、X射线衍射仪及电化学工作站研究后续热处理对化学镀层组织形貌、相组成及其耐蚀性的影响。结果表明,制备的Ni-P镀层为非晶态,而Ni-W-P镀层为纳米晶结构,两者在3.5%NaCl水溶液中的耐蚀性相当。热处理可以明显提高Ni-W-P镀层的耐蚀能力,但却稍微弱化Ni-P镀层的耐蚀能力,热处理后的Ni-W-P层自腐蚀电位相对于未处理的化学镀Ni-W-P或Ni-P层提高了约150 mV。
The electroless Ni-P and Ni-WP coatings were electrolessly plated on AZ91D magnesium alloy. The effects of subsequent heat treatment on the morphology, phase composition and corrosion resistance of electroless plating were studied by scanning electron microscopy, X-ray diffraction and electrochemical workstation . The results show that the prepared Ni-P coating is amorphous and the Ni-W-P coating is nanocrystalline. The corrosion resistance of the Ni-P coating in 3.5% NaCl aqueous solution is comparable. Heat treatment can significantly improve the corrosion resistance of Ni-WP coating, but slightly weakened the corrosion resistance of Ni-P coating. The self-corrosion potential of Ni-WP layer after heat treatment is lower than that of untreated electroless Ni-WP or Ni-P The layer is raised by about 150 mV.