迄今为止,有关电沉积单金属和电结晶,人们还不是探究的很透彻。由于金属共沉积需考虑2种或2种以上金属电沉积规律,以此,金属共沉积的规律和金属共沉积的理论是很难研究的。能形成合金共沉积的前提是:首先,在水溶液中合金必须有至少一种金属能单独沉积出来;其次,对于两种金属的析出电位要相等或大致相等,即φ析1 = φ析2[1]; 此外,如能形成金属间化合物的两种金属,往往在阴极上沉积出来的沉积物会是这个化合物。但是一般来说,金属的析出电位不会和标准电位相等,有时候差别还会很大,预测金属是否能共沉积用标准标准电位来衡量还是不够全面的,因为析出电位受到很多方面的影响,如离子的过电位,离子的络合状态以及金属离子的放电会相互影响等[13]。58137
含有钼或钨与铁类金属合金在各种技术应用广泛,钼的理化性质类似于钨但略差,然而,钼是一个更经济的选择,因为它便宜得多。金属钼具有良好的耐蚀性,在合金中加人钼,得到的合金能有高硬度,高耐磨,耐热,耐腐蚀以及良好的电催化性能。然而,论文网从水溶液中电沉积金属纯钼一直行不通,镀液中存在铁族元素时才有可能发生诱导共沉积。福岛认为诱导共沉积的机制是MoO42-离子在电沉积过程中,在阴极上还原成Mo4+的低价氧化物,有铁族元素存在下,能被铁族元素的不成对电子所结合的原子态氢还原成金属Mo并与之共沉积。总之,MoO42-不能直接还原成金属钼,需要其他元素存在,因而使其难以电沉积[14]。
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