为提高HSn62-1铜合金表面抗点蚀能力,解决高铝青铜涂层制备过程中相变和氧化造成涂层耐腐蚀性能降低的问题,采用低温超音速喷涂技术,在HSn62-1铜合金表面制备不含γ2相的高铝青铜涂层.利用场发射扫描电镜(SEM)、电子能谱仪(EDS)、X射线衍射仪等分析粉末和涂层的组织结构、表/截面形貌等特征;利用电化学工作站、盐雾腐蚀试验箱等测定分析NaCI溶液环境中涂层及基体的耐腐蚀性能及失效机制.结果表明:制备的高铝青铜涂层结构致密,结合良好,无池相和氧化夹杂生成,涂层腐蚀敏感性均一;涂层自腐蚀电流密度为6.938 μA/cm2,较HSn62-1铜合金基体降低了1个数量级,涂层自身具有较好的耐腐蚀性能,可有效阻挡腐蚀介质向涂层更深处渗入;盐雾环境中,高铝青铜涂层表面腐蚀产物薄膜反复地剥落和生成使其腐蚀失效机制宏观上表现为均匀腐蚀.
To improve the pitting resistance of HSn62-1 brass alloy and solve the phase transition and oxidation of aluminumrich bronze coating in the process of preparing,an aluminum-rich bronze coating excluding γ2 phase was prepared by low thermal supersonic spraying technique on HSn62-1 brass alloy surface.Microstructure and morphology of the coating were investigated by SEM,EDS and XRD.Corrosion properties were investigated by electrochemical workstation.The results show that the Al-rich coating possesses high density and good bonding state.γ2 phase and oxides are not detected in the coating.Corrosion current density achieved from polarization curves is 6.938 μA/cm2 on the coating,which is ten times lower than the current density on substrate.The result of lower corrosion rate of the coating gains insight into its promising anti-corrosion application in harsh environments.Moreover,the coating offers a long-term corrosion protection in the salt spraying environment for HSn62-1 brass alloy,and the failure mechanism of aluminum-rich bronze coating is uniform corrosion on macro scale based on repeated formation and peeling for corrosion film.
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