7075铝合金化学镀对镍磷合金镀膜组织和性能的影响

金属表面处理直接影响7075铝合金的力学性能及耐腐蚀性能.以7075-T6铝合金为基体,采用化学镀(EN)技术在光滑基体表面均匀镀覆一定厚度的镍磷(Ni-P)镀膜,镀膜厚度分别为3.64、5.87和7.33 μm,并通过扫描电子显微镜(SEM)、X射线衍射(XRD)、硬度测试及电化学工作站等手段分析膜层特性及膜厚对70...

Effect of electroless for 7075 aluminum alloy on microstructure and properties of Ni-P alloy coatings

Surface treatment directly affects mechanical properties and corrosion resistance of 7075 aluminum alloy. The base material used in the experiment was 7075-T6 aluminum alloy, the Ni-P coating with a certain thickness was fabricated by electroless nickel (EN) on the surface of smooth substrate surface, and the coating thicknesses were 3.64, 5.87 and 7.33 μm, respectively. The effect of characteristics and thickness of the coating on mechanical and corrosion properties of 7075-T6 aluminum alloy was analyzed using methods such as scanning electron microscope (SEM), X-ray diffraction (XRD), hardness test and electrochemical workstation. The experimental results showed that electroless nickel plating could form Ni-P layer on the surface of 7075 aluminum alloy, and the Ni-P coating was observed by SEM, which was tightly bonded to the substrate. The XRD analysis showed that the coating presented a microcrystalline morphology, and the coating showed good adhesion through observation by Rockwell-C indentation test. In terms of mechanical properties, the fatigue strength decreased slightly, and the elongation decreased more obviously, while the hardness, yield strength, tensile strength and elastic modulus were significantly improved. In terms of corrosion resistance, the Ni-P coating could significantly improve the corrosion resistance of the surface for 7075-T6 aluminum alloy by one order of magnitude, and the base material can be better protected.