Al对Cu-20Ni-19Fe合金微观组织和高温抗氧化性能的影响

Effect of Al on the microstructure and high temperature oxidationperformance of Cu-20Ni-19Fe alloy

为了解决Cu-Ni-Fe惰性阳极在铝电解过程中高温抗氧化性能差的问题,采用真空熔炼法制备不同Al含量的Cu-20Ni-19Fe-x Al(x=0%,6%,8%,10%,质量分数,下同)合金,于850℃和1.013×10^(5) Pa氧分压下进行高温氧化实验,氧化时间为100 h,研究Al添加量对合金微观组织结构及高温氧化性能的影响。结果表明:铸造Cu-20Ni-19Fe合金由富Ni/Fe的枝晶相(γ_(1))和富Cu,Ni的基体相(γ_(2))组成;添加6%Al的Cu-20Ni-19Fe合金,Al固溶在合金基体中;添加8%和10%Al的Cu-20Ni-19Fe合金,微观组织中形成了针状或块状NiAl相,且NiAl相随Al含量的增加而增多;Cu-20Ni-19Fe合金在850℃和1.013×10^(5) Pa氧分压下氧化动力学呈直线规律;添加Al元素后,合金的高温氧化动力学曲线由直线转变为指数规律,Al含量越高,合金氧化速率指数越小。Al元素的加入提高了Cu-20Ni-19Fe合金的高温抗氧化性能,使其有望成为惰性阳极铝电解中的备选阳极材料。

In order to solve the problem of poor oxidation resistance of Cu-Ni-Fe inert anode at high temperature during aluminum electrolysis,Cu-20Ni-19Fe-x Al alloys(x=0%,6%,8%,10%)with different Al contents were prepared by vacuum melting method,and the alloys were used for the high temperature oxidation experiments which were carried out at 850℃with oxygen partial pressure of 1.013×10^(5) Pa and oxidation time of 100 h,and the effects of Al addition on the microstructure and high temperature oxidation properties of the alloy were investigated.The results show that the as-cast Cu-20Ni-19Fe alloy is composed of Ni/Fe-rich dendritic phase(γ_(1))and Cu/Ni-rich matrix phase(γ_(2));Al was dissolved in the Cu-20Ni-19Fe alloy matrix with 6%content of Al added;The needle-like or blocky NiAl phase was formed in the microstructure of Cu-20Ni-19Fe alloy with 8%and 10%Al added;The content of NiAl phase increases with the increasing addition of Al;The oxidation kinetics of Cu-20Ni-19Fe alloy follow the straight line under 850℃and oxygen partial pressure of 1.013×10^(5) Pa;After the addition of Al,the oxidation kinetic curve of Cu-20Ni-19Fe-x Al alloy follow an exponential law,and the oxidation rate index of the Cu-20Ni-19Fe-x Al alloy was much smaller with more content of Al.The high-temperature oxidation resistance of Cu-20Ni-19Fe alloy was greatly improved by the addition of Al,which proves the Cu-20Ni-19Fe alloy may be used as an alternative anode material for aluminum electrolysis.