4032铝合金活塞在中高温氨水环境中的腐蚀行为研究

Study on Corrosion Behavior of 4032 Aluminum Alloy Piston in High Temperature Ammonia Environment

近年来,氨(NH_(3))作为内燃机燃料得到广泛关注。氨燃烧会产生大量的水,然而未完全燃烧的氨在有水存在的中高温环境中对发动机活塞部件可能会产生腐蚀。以4032铝合金活塞材料为研究对象,研究其在恒温200℃下25%(质量分数)氨水溶液中的腐蚀行为,着重探讨了在不同时间尺度下铝合金的腐蚀失重、腐蚀产物形态、腐蚀电化学性质。结果表明,4032铝合金在中高温氨水环境中的腐蚀速率随浸泡时间的延长呈先增强后减弱的变化趋势,腐蚀产物主要以Al(OH)_(3)为主。随着浸泡时间的延长,4032铝合金的腐蚀电位Ecorr和极化电阻Rp均逐渐增大,腐蚀电流密度Jcorr逐渐减小,并进一步解析了其腐蚀机理。

In recent years,ammonia(NH_(3))has received widespread attention as a fuel for internal combustion engines.Ammonia combustion produces a large amount of water,but incomplete combustion of ammonia may cause corrosion to engine piston components in medium to high temperature environments with water present.In this work,taking 4032 aluminum alloy piston material as the research object,the corrosion be-havior in a 25%(mass fraction)ammonia solution was analyzed at a constant temperature of 200℃,and the corrosion weight loss,corrosion product morphology and corrosion electrochemical properties of aluminum alloys were explored emphatically at different time scales.Results showed that the corrosion rate of 4032 aluminum alloy in medium to high temperature ammonia environment exhibited a trend of first increasing and then decreasing with the prolongation of soaking time,and the corrosion products were mainly Al(OH)_(3).With the extension of soaking time,the corrosion potential Ecorr and polarization resistance Rp of 4032 aluminum alloy increased gradually,while the corrosion current density Jcorr decreased gradually,which further analyzed the corrosion mechanism.