Two methods for impeding the detrimental impact of iron (Fe) impurity in magnesium (Mg) alloys on the corrosion properties are studied: the addition of manganese (Mn) and the selection of melting temperature. Experimental work was carried out on Mg and AZ91 alloys with selected additions of Mn and selected settling temperatures. The settling velocity was evaluated using the Stokes equation. Extensive thermodynamic calculations using different databases in comparison were performed and supported by experimental observations. The conditions for the formation of the different types of precipitate phases and their detailed composition are revealed. Practical guidelines for settling temperature and time are proposed. The tolerance limit of Fe, expressed by the critical Fe/Mn ratio, could be related to key phase boundaries in the calculated Mg-Aluminum (Al)-(Zn)-Mn-Fe phase diagrams for AM and AZ types of alloys.

研究了两种阻止镁合金中铁杂质对腐蚀性能的有害影响的方法：添加锰和选择熔化温度。在选定的Mn添加量和选定的沉降温度下对Mg和AZ91合金进行了实验工作。使用斯托克斯方程评估沉降速度。进行了比较，使用不同的数据库进行了广泛的热力学计算，并得到了实验观察的支持。揭示了形成不同类型的沉淀相的条件及其详细的组成。提出了解决温度和时间的实用指南。铁的公差极限，用临界铁/锰比表示，