热处理温度对镀镍钴钢带耐腐蚀性能的影响

对镀镍钴钢带进行不同温度的热处理,热处理温度为550℃、650℃、750℃,保温时间3h。采用电化学方法测试了不同热处理温度下镀镍钴钢带在1.0%NaCl和0.1%H2SO4混合溶液及10%NaOH溶液中的耐腐蚀性能,并通过扫描电子显微镜(SEM)、能谱分析仪(EDS)和X射线衍射仪(XRD)分析了镀镍钴钢带在不同热处理温度下的微观形貌、成分及织构变化。结果表明,随着热处理温度的升高,镀镍钴钢带表面镀层的晶粒尺寸逐渐长大,镀层和基底间形成了镍/钴/铁扩散层;当热处理温度为650℃时,镀镍钴钢带在1.0%NaCl和0.1%H2SO4混合溶液及10%NaOH溶液中的耐腐蚀性能均为最好的,当热处理温度超过650℃后其耐腐蚀性能降低。这说明合适的热处理温度能有效地提高镀层的耐腐蚀性能。

Effect of Heat Treatment Temperature on Corrosion Resistance of Electrodeposited Ni-Co Coating on Steel-Strip

The steel-strip with nickel-cobalt coating was heat treated for 3 h at the temperatures of 550 ℃,650 ℃ and 750 ℃.Electrochemical was used to test the corrosion resistance of nickel-cobalt coating on steel-strip in 1.0% NaCl and 0.1% H2SO4 mixed solutions and 10% NaOH solution before and after heat treatment.The morphology,composition and texture orientation of nickel-cobalt coating on steel-strip at different temperatures were studied by scanning electron microscopy(SEM),energy dispersive spectrometry(EDS) and X-ray diffraction(XRD).The results showed that with the increase of heat treatment temperatures,the grain size of nickel-cobalt coating increased correspondingly,a nickel-cobalt/iron diffusion layer between coating and substrate was formed.When the heat treatment temperature was 650 ℃,the corrosion resistance of nickel-cobalt coating on steel-strip was the best both in 1.0% NaCl-0.1% H2SO4 mixed solution and 10% NaOH solution,and then decreased when the temperature exceeded 650 ℃,indicating that a suitable heat treatment temperature can improve the corrosion resistance of the coating.