摘要
近来AZ91D镁合金被用到汽车发动机中,而以往对其在冷却液中腐蚀行为的报道较少。采用浸泡和电化学测试方法,研究了汽车发动机用材AZ91D镁合金在不同体积分数乙二醇模拟冷却液中的腐蚀行为及腐蚀机理。结果表明:随着乙二醇体积分数的增加,AZ91D镁合金的腐蚀速率呈现先降低后增加的趋势,在乙二醇体积分数为80%时腐蚀速率最小,合金的腐蚀速率随着腐蚀时间的延长呈降低趋势;AZ91D镁合金在乙二醇-水溶液中会形成具有自愈合作用的Mg O/Mg(OH)2腐蚀产物膜,可以对合金表面起到良好的保护作用;AZ91D合金在乙二醇-水溶液中以析氢腐蚀为主,而在纯乙二醇中以Mg和乙二醇的化学腐蚀为主。
Corrosion behavior and mechanism of the AZ91 D alloy immersed in the simulated coolant with various volume fractions of glycol were investigated by immersion test and electrochemical method. Results showed that the corrosion rate of AZ91 D alloy decreased first and then increased with the increase of the volume fraction of glycol,and the lowest corrosion rate was obtained when the volume fraction of glycol was 80%.As the immersion time increased,the corrosion rate of AZ91 D alloy decreased. The corrosion product MgO / Mg( OH)2film of AZ91 D alloy in glycol water solution which had a self-healing function,could effectively protect the alloy. The corrosion mechanism in glycol water solution was mainly hydrogen-evolution corrosion while in pure glycol was mainly chemical corrosion of Mg and glycol.
出处
《材料保护》
CAS
CSCD
北大核心
2015年第7期55-57,65,共4页
Materials Protection
