Electrodeposition of Coherent Deposits of Refractory Metals I . Niobium
Electrodeposition of Coherent Deposits of Refractory Metals I . Niobium
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DOI：
10.1149/1.2423521
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发表时间：
1967
影响因子：
3.9
通讯作者：
G. W. Mellors;S. Senderoff
中科院分区：
文献类型：
--
作者：
G. W. Mellors;S. Senderoff
已经找到了一种通过熔盐电解电沉积难熔金属的连贯致密沉积物的通用方法。通过将难熔金属氟化物溶解在碱金属氟化物的混合物中，可以沉积铬、铪、钼、铌、钽、钨、钒和锆的连贯厚涂层。不仅所有情况下的沉积物都具有理论密度，而且在大多数情况下都非常纯净，并且机械性能等于或优于市售的电子束熔化材料。虽然不同金属在电解质的组成和难熔金属的价态细节上存在差异，但一般过程可以用最先研究的金属之一铌来描述。使用商业纯铌作为阳极材料，在约775℃的温度和约50ma/cm 2 的电流密度下，从碱金属氟化物混合物中约10w/o NbF 5 的溶液中电沉积铌金属。阳极和阴极效率接近 100%，经常获得硬度为 85-100 DPH 的沉积物。获得的沉积物密度为理论值的 99.8% 或更高，并且镀液的均镀能力优于通常与商业镀镍相关的镀液。对基材没有大的限制，因为已经使用了钢、不锈钢、石墨、铜、哈氏合金等。电沉积厚度高达 I/4 英寸，表面极其光滑。沉积物的微观结构是典型的柱状晶粒结构，通常在无添加剂的电沉积中观察到，并且其健全性已通过机械测试得到证实。此外，还成功完成了电解精炼。
A general method has been found for the electrodeposition of coherent, dense deposits of refractory metals by electrolysis of molten salts. By dissolving the refractory metal fluoride in mixtures of alkali metal fluorides, one may deposit coherent thick coatings of chromium, hafnium, molybdenum, niobium, tantalum, tungsten, vanadium, and zirconium. Not only do the deposits in all cases have the theoretical density, but in most cases are extremely pure and equal to or better in mechanical properties than electron beam melted material available commercially. While differences exist from metal to metal in the details of the compositions of the electrolyte and the valence state of the refractory metal, the general process can be described in terms of one of the first metals studied, niobium. Niobium metal is eleetrodeposited from a solution about I0 w/o NbFs in a mixture of alkali fluorides at a temperature of about 775~ and a current density of about 50 ma/cm 2 with commercially pure niobium as anode material. Anode and cathode efHciencies are close to 100% and deposits with hardness of 85-100 DPH are obtained regularly. Deposits with densities of 99.8% of theoretical and higher are obtained and the throwing power of the bath is better than that usually associated with commercial nickel plating. There is no major restriction on substrates, since steel, stainless steel, graphite, copper, Hastelloy alloys, and others have been used. Thicknesses up to I/4 in. have been electrodeposited with a surprisingly smooth surface. The microstructures of the deposits are the typical columnar grain structure usually observed in electrodeposits without addition agents and their soundness has been confirmed by mechanical testing. Also, successful electrorefining has been accomplished.