镁铝钆合金在空气中的氧化与燃烧

Oxidation and combustion of Mg-Al-Gd alloy in air

摘要:

本文研究了在镁铝质量比为20:80的镁铝合金中加入稀土金属钆后，合金在空气中的氧化与燃烧特性。借助TG-DSC, SEM, XRD, EDS以及高速摄像仪等仪器对Mg-Al-Gd合金的氧化、燃烧过程及产物进行分析。结果表明：相对于不含钆的Mg-Al合金，Mg-Al-Gd合金在空气中的点火温度较低，约为487.6℃。在TG-DSC实验中，镁铝钆合金的氧化分为两个阶段，第一个阶段为镁的氧化反应，第二个阶段为氧化镁、铝以及氧气的反应，反应生成MgAl2O4。当Mg-Al-Gd合金在空气中燃烧时，合金粒子表面会形成一层薄的致密的氧化层，氧化层限制了合金粒子固相或液相的氧化，促进其气相燃烧，同时也导致燃烧出现喷射现象。燃烧没有生成MgAl2O4，而是形成了一种的新的产物AlN。

Abstract:

In this paper, the oxidation and combustion characteristics of Mg-Al-Gd alloy with the 2/8 mass ration of Mg/Al have been studied. The oxidation and combustion process as well as the reacted and unreacted particles of the alloy have been analyzed by using TG-DSC, SEM, XRD, EDS and high-speed camera. The results show that the ignition temperature of Mg-Al-Gd alloy in air is about 487.6 ℃, which is lower than the ignition temperature of Mg-Al alloy. Oxidation of the Mg-Al-Gd alloy in TG-DSC experiments is a staged process：The first stage is the oxidation of Mg and the second stage is the formation of MgAl2O4. When burning in air, a thin compact oxide layer will be formed firstly on the particle surface. This layer can hinder the solid or liquid phase oxidation and promote the gas phase combustion of the alloy. The combustion products of the Mg-Al-Gd alloy in air mainly contain MgO and AlN, MgAl2O4 has not been detected in the products.