铸态和喷射成形ZA35-3．5Mn合金盐雾腐蚀行为

Salt Spray Corrosion Behavior of As-cast and Spray Formed ZA35-3.5Mn Alloy

采用喷射沉积技术制备Mn含量为3.5%的ZA35合金,在质量分数为3.5%的NaCl盐雾条件下研究ZA35合金的腐蚀行为。结果表明,喷射成形态合金腐蚀动力学曲线满足抛物线型,腐蚀速率远远低于符合直线动力学规律的铸态合金。产生腐蚀的原因是富Zn-η相的优先溶解。铸态合金中大量片状富Mn相MnAl6的存在,提供了η相溶解的快速通道,加速腐蚀;喷射成形态合金中Mn全部固溶,降低了η相和α相电位差,减缓腐蚀。

Corrosion behavior of as-cast and spray formed ZA35 alloy containing 3.5% Mn was observed in 3.5% NaCl salt spray atmosphere.The results indicate that the corrosion dynamic curves of spray formed alloy are accordant with the parabola curves,and the corrosion rate is remarkably slower than that of as-cast alloy which is accordant with linear dynamics.The corrosion mechanism is attributed to the prefer dissolution of η phase.The existence of amounts of lamellar MnAl6 phase provides a rapid channel for η phase dissolution in as-cast ZA35 alloy,resulting in the acceleration of corrosion,while Mn in the spray formed is totally solved,which decreases the potential difference between η phase and α phase,relieving the corrosion behavior.