Al-Ga-Mg-Sn多元铝合金的水解产氢行为

Hydrogen generation by hydrolysis of Al-Ga-Mg-Sn multi-element aluminum alloy

采用坩埚电阻炉熔炼制备了6种不同成分的Al-Ga-Mg-Sn多元铝合金。利用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和产氢性能测试装置等系统研究了多元铝合金铸态下的显微组织和相组成、水解反应产物的相组成以及在30、50、70和90℃纯水中的产氢速率和产氢量。结果表明:Al-Ga-Mg-Sn多元铝合金铸态组织由铝基体相、Mg_2Sn和Ga_2Mg相组成,水解反应产物主要为Al O(OH)等;同一成分试样,产氢速率和产氢量均随温度的升高而增加;不同成分试样在同一温度下,产氢速率和产氢量与低熔点元素Ga含量和合金相中铝基体相/第二相的比例有关;产氢的起始温度主要由低熔点元素Ga+Sn含量决定。进一步分析发现:水解产氢行为发生后,产氢速率k与热力学温度T服从阿伦尼乌斯公式,即ln k与1/T呈线性规律。

Six kinds of Al-Ga-Mg-Sn multi-element aluminum alloys with different compositions were prepared by crucible resistance furnace. The microstructure and phase composition of as-cast aluminum alloy, the phase composition of the hydrolyzate, the hydrogen generation rate and hydrogen yield in pure water at 30, 50, 70 and 90 ℃ were investigated by means of optical microscope (OM),scanning electron microscopy (SEM),X-ray diffraction (XRD) and hydrogen generation performance test device. The results indicate that the as-cast Al-Ga-Mg-Sn multi-phase aluminum alloy consists of an aluminum matrix phase, Mg2Sn and Ga2Mg phases and the hydrolyzate is mainly AlO(OH).The hydrogen generation rate and hydrogen yield increase with the increment of temperature for the same composition. At the same temperature, for the samples with different compositions, the content of the low melting point element Ga, the proportion of the aluminum matrix phase and the second phase in the alloy phase depend on the hydrogen generation rate and hydrogen yield. The starting temperature of hydrogen generation is mainly determined by the content of low melting point elements Ga and Sn. Further analysis finds that the hydrogen generation rate k and thermodynamic temperature T obey Arrhenius formula, namely the ln k is linear with 1/T after hydrogen generation by hydrolysis occurring.