高锰ZA35合金中富锰相的电化学行为

Electrochemical Behavior of Mn-enriched Phase in High Mn ZA35 Alloy

为了探索析出的富锰相对高锰ZA35合金电化学腐蚀性能的影响规律,根据高锰ZA35合金中富锰相的元素组成,熔炼出析出相MnAl6。采用动电位极化方法测试了富锰相MnAl6和ZA35-1.2Mn合金在NaCl水溶液中的开路电位和极化曲线,利用X-射线衍射仪(XRD)检测了合金的相组成。结果表明,随着NaCl溶液温度升高,合金的开路电位下降,并且富锰相MnAl6较ZA35-1.2Mn合金的开路电位低,富锰相MnAl6较ZA35-1.2Mn合金腐蚀电流密度大。ZA35-1.2Mn合金在NaCl含量为3.5%的溶液中,析出的富锰相MnAl6将作为阳极区优先溶解。

Precipitate phase MnAl6 was fabricated based on element distribution of Mn-enriched in high Mn ZA35 alloy to understand effects of precipitated phase on electrochemical behavior of high Mn ZA35 alloy. Open circuit potential against time and polarization curves of Mn-enriched phase MnAl6 and ZA35-1.2Mn in NaCl aqueous solution were measured by potential dynamic polarization, and phase constituent of the alloy was examined by XRD （X-ray diffraction）. The results show that with increasing in temperature of NaCl solution, the open-circuit potential （OCP）of the alloy is shifted gradually into the negative direction, and the OCP of the Mn-enriched phase MnAl6 is lower than that of ZA35-1.2Mn alloy, while corrosion current density is higher than that of the ZA35-1.2 Mn alloy. The precipitate MnAl6 phase in ZA35-1.2Mn alloy is dissolved preferentially as anode zone in 3.5% NaCl aqueous solution.