冷喷涂铜锌合金复合涂层的腐蚀行为研究

Study on Corrosion Behavior of Copper Zinc Alloy Composite Coating Prepared by Cold Spraying

研究了镁合金上低压冷喷涂法制备的铜锌合金复合涂层的结构和耐蚀性。采用低压冷喷涂技术在镁合金表面制备铜锌合金复合涂层。通过微观观察、结合力测试、电化学极化法和电化学阻抗谱测试研究了该涂层的结构和腐蚀行为。结果表明:采用低压冷喷涂法可在镁合金上制备铜锌合金复合涂层,涂层中合金颗粒发生大塑性变形后紧密结合,涂层结构致密,孔隙率低。铜锌合金复合涂层与镁合金基体具有较强的结合性能,结合力测试得到的结合力超过23MPa,且拉伸断口发生在涂层内部,涂层和基体间结合力强。铜锌合金复合涂层在盐溶液中具有较好的耐蚀性,其自腐蚀电位明显高于镁合金基体的,自腐蚀电流显著小于基体的,长期浸泡腐蚀仍然保持较高的电阻,涂层长效防护效果优异。

The structure and corrosion resistance of copper zinc alloy composite coating prepared by low-pressure cold spraying on magnesium alloys were studied. The copper zinc alloy composite coating was prepared on the surface of magnesium alloy by low-pressure cold spraying technology. The structure and corrosion behavior of the coating were studied by microscopic observation, binding force test, electrochemical polarization method and electrochemical impedance spectroscopy test. The results show that the low-pressure cold spraying method can be used to prepare copper zinc alloy composite coatings on magnesium alloys. The alloy particles in the coatings are tightly bonded after large plastic deformation,and the coating structure is dense and the porosity is low. The copper zinc alloy composite coating has a strong bonding property with the magnesium alloy substrate. The bonding force obtained by the binding fore test exceeds 23 MPa, and the tensile fracture occurs inside the coating. The bonding force between the coating and the substrate is strong. The copper zinc alloy composite coating has better corrosion resistance in salt solution. Its self-corrosion potential is significantly higher than that of the magnesium alloy substrate. The self-corrosion current is significantly smaller than that of the substrate. The long-term immersion corrosion maintains high resistance, and the coating has long-lasting excellent protection effect.