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Vaaler 和 Holt 二氏曾用硫酸钴、钨酸钠、柠檬酸和氢氧化铵(氢氧化铵是用来调节酸度的)的混合溶液,使普通金属电镀上一层钴钨合金。本文作者参考二氏的初步试验,再继续研究,求得电镀的各项条件,对于钴钨合金的成分和阴极电流效率的关系如下:(1)在中性附近时(pH=6.4—7.8),电镀溶液的酸度对于合金成分和阴极电流效率的影响并不很显著;(2)阴极电流密度增加时,合金中钨的含量稍有增加,而阴极电流效率则随之递减;(3)电镀溶液的温度增高时,合金中钨的含量和阴极电流效率都随之增加。含钨最多(54.19%)而且光亮平滑的钴钨合金面,可在下列条件下获得之:电镀溶液每公升含氯化钴(CoCl_2·6H_2O)16.6克,钨酸钠(Na_2WO_4·2H_2O)75克,柠檬酸(C_6H_8O_7·H_2O)66克,并加氢氧化铵调节酸度至中性附近;温度为摄氏70度,阴极电流密度每平方分米(dm.)20安培。
Vaaler and Holt II used cobalt sulfate, sodium tungstate, citric acid and ammonium hydroxide (ammonium hydroxide is used to adjust the acidity) of the mixed solution, ordinary metal plating on a layer of cobalt tungsten alloy. The authors refer to two preliminary tests, and then continue to study and find the conditions of electroplating, the composition of the cobalt-tungsten alloy and the cathode current efficiency is as follows: (1) near the neutral (pH = 6.4-7.8) , The acidity of the plating solution has no significant effect on the alloy composition and the cathode current efficiency; (2) when the cathode current density increases, the content of tungsten in the alloy slightly increases, while the cathode current efficiency decreases; (3) As the temperature of the solution increases, both the tungsten content and the cathode current efficiency in the alloy increase. The bright and smooth cobalt tungsten alloy with the highest tungsten content (54.19%) is obtained under the following conditions: 16.6 g of cobalt chloride (CoCl 2 · 6H 2 O) and 75 g of sodium tungstate (Na 2 WO 4 · 2H 2 O) per liter of plating solution , And 66 g of citric acid (C_6H_8O_7 · H_2O) with ammonium hydroxide added to adjust the acidity to near neutral; the temperature is 70 degrees Celsius and the cathode current density is 20 amperes per square decimeter (dm.).