我厂生产用双金属片的化学成分:主面含铜60.5～63.5%,铁0.15%,余量为锌。被面含镍35～37%,铬0.15%,碳不大于0.2%,余量为铁。几年来要求分层分析,没有得到解决,其中主要向题就是如何正确制取试样的向题。近来,根据中西南地区络合滴定资料中钢丝铜锌镀层中锌的络合滴定法一文中介绍,铜锌镀层溶于NH_4OH 及 H_2O_2中,但钢丝不溶。对双金属片来说,黄铜层是能溶解一部分,〈溶解次数愈多,铜层溶解也较多〉,但总是溶解不完全,这样,仅能解决黄铜层一面的分析,对铁镍层还是不能解决。经过我们多次试验摸索,曾先后采用过不少溶剂处理,都无济于事。最后,我们认为在醋酸存在下滴加 H_2O_2,黄铜层才能完全溶解〈铁镍层稍有溶解但没有关系〉,然后,将剩下不溶解部分擦干,洗净作为定镍铁试样。试验结果表明,这种取样方法作为双金 I plant the production of bimetal chemical composition: the main surface of copper 60.5 ~ 63.5%, 0.15% iron, the balance of zinc. Nickel is 35 to 37%, chromium 0.15%, carbon not more than 0.2%, the balance of iron. Asked for years stratified analysis, has not been resolved, one of the main question is how to correctly prepare the sample questions. Recently, according to the complexometric titration method of zinc in the copper-zinc coating in the complexation titration data of Central-Southwest China, the copper-zinc coating dissolves in NH 4 OH and H 2 O 2, but the wire is insoluble. For the bimetal, the brass layer is able to dissolve part, "the more dissolved, the copper layer is more dissolved>, but always dissolved incomplete, so that only the analysis of the brass layer can be solved, the iron Nickel layer still can not be solved. After many trials we have explored, has adopted a lot of solvent treatment, are of no avail. Finally, we think that H 2 O 2 is added dropwise in the presence of acetic acid to completely dissolve the brass layer, but it does not matter if the iron-nickel layer dissolves slightly. Then, the remaining insoluble portion is dried and cleaned as a fixed nickel-iron sample. Test results show that this sampling method as a double gold