Mg添加对Al-Ga-In-Sn合金水解产氢性能的影响

Effect of Mg addition on hydrolysis hydrogen production of Al-Ga-In-Sn alloy

研究了不同含量的Mg对Al-3Ga-3In-3Sn铸态铝合金水解产氢性能的影响,采用X射线衍射(XRD)、扫描电镜(SEM)和能谱仪(EDS)分析了铝合金的显微组织和物相结构。结果表明:Mg添加导致铝合金析出Mg_(2) Sn新相,Al晶粒得到明显细化,由柱状变为棒状或粒状,Al晶界相由带状转变为花瓣状,同时铝合金表面分布大量裂纹缺陷。Mg含量为0.5%时铝合金的产氢性能最好,1 g的Al-3Ga-3In-3Sn-0.5Mg铝合金在温度为80℃条件下反应30 min,最大产氢量1300 mL、产氢速率达217 mL/(min·g),产氢转化率可达95.7%;当含Mg量低于2%时,Al晶粒周围低熔点晶界相和Mg_(2) Sn与Al形成原电池是铝合金提高产氢性能的主要因素;Mg含量超过2%后,产氢速率下降主要是由于随着Mg含量增加,铝合金的晶界相形态发生改变,与水接触面积减少,降低了其水解反应活性所致。

Effect of different content of Mg on hydrolysis hydrogen production of as-cast Al-3Ga-3In-3Sn aluminum alloy was studied.Microstructure and phase of the aluminum alloys were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS).The results show that the addition of Mg results in the precipitation of new Mg_(2) Sn phase in the aluminum alloy,the grain size of Al is obviously refined from columnar to rod-like or granular,the morphology of grain boundary phase is transformed from band-like to petal-like,and a large number of crack defects are distributed on the surface of the aluminum alloy.The aluminum alloy with Mg content of 0.5%has the best hydrogen production performance.When 1 g of Al-3Ga-3In-3Sn-0.5Mg aluminum alloy is reacted with water at 80℃for 30 min,the maximum hydrogen production is 1300 mL,the hydrogen yield rate is 217 mL/(min·g),and the hydrogen production conversion rate is 95.7%.When the Mg content is less than 2%,the low melting point grain boundary phase around the Al grain and the formation of micro-cell of Mg_(2) Sn phase and Al are the main factors to improve the hydrogen production performance of the aluminum alloy.When Mg content exceeds 2%,the decrease of hydrogen production rate is mainly due to the change of grain boundary phase morphology of the aluminum alloy with the increase of Mg content,and the decrease of contact area with water,which reduces its hydrolysis activity.