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镁合金的氧化膜多孔、不密集,不能保护金属不被氧化(其他金属表面附着一层很厚的氧化膜时,对金属具有防护作用)。在空气中,特别是在高温下,随着温度与时间的增加,氧化程度也随着增加,液态的镁甚至会燃烧起来。因此,在空气中熔锻镁合金是不可能的,需要采取特殊方法。这种特殊熔炼方法可在下述几种条件下进行:1．真空下; 2．合金中加入降低氧化性的金属; 3．在复盖着的熔剂层的保护下。但是,在真空中熔炼镁合金,现在在工业上还有困难,还未采用,而在合金中加入降低氧化性的金属问题,现在可用的金属也只有铍(Be)一种,其他还不适合,铍可以使金属表面氧化膜严密,但加入数量有限,超过一定限量时,对合金性能有害,旦不能从根本上解决氧化问题(只能减少氧化的程度)。因此,唯一的方法是在熔剂的保护层下进行。
Magnesium alloy oxide film porous, non-dense, can not protect the metal from oxidation (other metal surface attached to a thick oxide film, the metal has a protective effect). In the air, especially at high temperatures, as the temperature and time increase, the degree of oxidation also increases with the liquid magnesium even burning. Therefore, it is impossible to melt the magnesium alloy in the air and require special methods. This special melting method can be carried out in the following conditions: 1. Under vacuum; 2. Add the alloy to reduce the oxidation of metals; 3. Under the protection of covered flux layer. However, smelting magnesium alloys in vacuum is still industrially difficult and has not been adopted yet. However, the addition of an oxidizing metal to the alloys is only available for beryllium (Be) and others are not suitable Beryllium can make the metal surface oxide film tight, but a limited number of addition, more than a certain limit, the performance of the alloy is harmful, once can not fundamentally solve the oxidation problem (only reduce the degree of oxidation). Therefore, the only way is under the protective layer of flux.