碳化硅复合镍磷合金涂层的组织结构、显微硬度及腐蚀性能研究

镍基复合涂层是一项有望替代电镀铬涂层的先进绿色环保表面处理技术。 本文在铝合金表面制备了纯 Ni、 NiP及其与SiC复合涂层， 利用SEM、 EDS和XRD研究了Ni、 NiP及其复合涂层的微观形貌、 成分与组织结构， 利用显微硬度计与电化学工作站研究了其硬度与耐腐蚀性能。 研究结果表明： SiC 复合电镀纯镍涂层的表面较为 粗糙， SiC 复合电镀镍磷合金涂层中晶粒轮廓明显； 电沉积镍磷合金涂层的相结构包括晶体 Ni2P、 Ni12P5 和非晶 NiP。 铝合金基体表面 Ni-P 合金涂层的显微硬度显著高于纯 Ni 涂层， 引入 SiC 纳米颗粒形成复合涂层可提高其 显微硬度； SiC 颗粒有助于提高复合涂层在氯化钠溶液中的腐蚀电位， 降低腐蚀电流密度， 提高其耐蚀性能。

Component, Structure, Micro-hardness and Anti-corrosion Properties of Silicon Carbide Composite Nickel-phosphorus Alloy Coating

Electro deposition of nickel and composite coatings has been developed as an advanced environmentally-friendly surface treatment technology for replacing chromium elctro-plating. In this research, pure nickel, nickel-phosphorus and their composite coatings have been electro-deposited on aluminium alloy surfaces. The surface morphology, component and structure are studied by SEM, EDS and XRD. Microhardness tester and electrochemical workstation are used to investigate the hardness and anti-corrosion properties. The results showed that the surfaces of SiC composite Ni coatings were roughness and the profile of NiP cells is distinct on NiP-SiC composite coatings. The structures of NiP-SiC composite coatings included crystalline Ni2P, Ni12P5 and amorphous NiP. The microhardness of NiP coatings on Al substrates was higher than that of pure Ni coatings. Introducing SiC nanoparticles to form composite coatings would improve the microhardness. Furthermore, SiC nanoparticles would increase the corrosion electric potential of the composite coatings in NaCl solution and decrease the electric current density, resulting in better anti corrosion properties.