雾化铝-镁合金粉缓慢加热氧化机理

Slow Heating Oxidation Mechanism of Sprayed Aluminum-magnesium Alloy Powder

为明确不同镁(Mg)含量的雾化铝-镁(Al-Mg)合金粉氧化反应历程,开展Al-Mg合金加热实验研究。采用热重分析-差示扫描量热法研究Al-Mg质量比分别为50∶50、80∶20、90∶10的雾化微米Al-Mg合金粉在空气环境下的缓慢加热氧化过程,并结合扫描电子显微镜和X射线粉末衍射仪,分析了雾化微米Al-Mg合金粉中Mg含量对氧化反应的影响。结果表明:随着雾化微米Al-Mg合金粉中Mg含量的增加,其起始反应温度逐渐降低,且雾化微米Al-Mg合金粉较Al粉反应更加完全;基于各个反应阶段的反应历程,提出了不同Mg含量的“核-壳”结构雾化Al-Mg合金粉在缓慢加热氧化过程中的热物理响应模型;采用热分析动力学法计算得到雾化Al-Mg合金粉各个阶段反应的活化能远小于纯Al粉,Mg的存在提高了雾化Al-Mg合金粉的反应速率。

The heating test of aluminum-magnesium(Al-Mg)was made to clarify the oxidation history of sprayed aluminum-magnesium alloy powders with different magnesium content.The slow heating oxidation processes of sprayed micro-aluminum-magnesium alloy powders with aluminum-magnesium ratio of 50∶50,80∶20 and 90∶10 in air environment were studied by TG-DSC method.The effect of Mg content in the sprayed micro-aluminum-magnesium alloy powder on the oxidation reaction is analyzed using scanning electron microscopy(SEM)and X-ray powder diffractometry(XRD).The results show that the initial reaction temperature decreases with the increase in Mg content in the sprayed micro-aluminum-magnesium alloy powder,and the atomized micro-aluminum-magnesium alloy powder reacts more completely than aluminum powder.Based on the reaction history of each reaction stage,a thermal physical response model of sprayed aluminum-magnesium alloy powders with different magnesium content in the process of slow heating oxidation is proposed.The activation energy of sprayed aluminum-magnesium alloy powder at various stages is calculated by thermal analysis kinetics method,which is much smaller than that of pure aluminum powder.The reaction rate of sprayed aluminum-magnesium alloy powder is improved in the presence of Mg.