Codeposition of Tungsten and Nickel from an Aqueous Ammoniacal Citrate Bath

Vaaler, L. E.; Holt, M. L.

doi:10.1149/1.3071730

Cited by 37 publications

(20 citation statements)

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“…It was later suggested (10) that the reduction of W w to the metal in the carbonate-tungstate bath appeared to be due to the presence of small amounts of iron present as an impurity in the materials used; this was also found to be true for the phosphate bath (11) and the citric acid bath (7). Other work (12) reported that Ni ++, Co ++, Fe ++ and Fe +++ definitely aid in the cathodic reduction of tungstates in the carbonate bath, in acid baths (13,14,15), and in other types of alkaline baths (16,17,18). The patents of Armstrong and iV[enefee (19) also mention certain of these metals as codepositing with tungsten.…”

Section: Reduction Of IV V~ To W ~ In the Presence Of Certain Cationsmentioning

confidence: 82%

Electrolytic Reduction of Aqueous Tungstate Solutions

Holt

Vaaler

1948

J. Electrochem. Soc.

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A "catalytic reduction" theory is proposed to explain the electrolytic reduction of aqueous tungstate solutions in the presence of codepositing metals such as iron, nickel, and cobalt. Two cathode reactions are suggested as being essential to the reduction process:Reaction A proceeds until the cathode is covered with a thin deposit of metal, IV[, which then acts as a catalyst for reaction B. When this metal catalyst is covered with a layer of tungsten reaction B stops and reaction A again proceeds to give a new catalyst surface; thus alternate layers of metal (Ni, Co, or Fe) and tungsten are deposited on the cathode. Evidence for this postulated mechanism is based in part OR polarographic studies, cathode potential measurements, and the laminated structure of the cathode deposits.

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Section: Reduction Of IV V~ To W ~ In the Presence Of Certain Cationsmentioning

confidence: 82%

Electrolytic Reduction of Aqueous Tungstate Solutions

Holt

Vaaler

1948

J. Electrochem. Soc.

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“…Holt and his students investigated the electrodeposition of IG-W alloys from ammonium citrate solutions (28). After complexation, atomic hydrogen reduction was suggested as a means to co-deposit IG-W alloys via a 2-step reduction process involving alternating deposition of the IG species catalyzing the reduction of the tungstate ion based on polarographic studies and cathode potential measurements.…”

Section: Electrodeposition Mechanismmentioning

confidence: 99%

Aqueous Electrodeposition and Mechanism of Iron Group-Vanadium Ternary Alloys

2011

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Composition of ternary CoFeV deposits can be varied and tailored by control of the [Fe]/[Fe + Co] solution molar ratios and solution pH. Near 2V Permendur compositions were obtained with B s of 2.35T and B s of 2.39T for direct current (DC) and pulse current (PC) deposits, respectively. Annealing deposits in vacuum at 820 o C for 2 hours increased B r to equivalent 2V Permendur. X-ray diffraction patterns show microstructures of mixed HCP, FCC and BCC planes, depending on deposit composition. Co-rich deposits had HCP preferred orientation but as Fe content increases HCP plane disappeared and Fe BCC plane became the preferred orientation. Surface morphology changed from a needle-like structure in Co-rich deposits to nodular appearance with increasing Fe content. A hydrogen atom mechanism for the reduction of the oxovanadium, Co(II) and Fe(II) within the heterodinuclear and heterotrinuclear biscitrate complexes is proposed. This mechanism is also applicable to aqueous electrodeposition of IG-Mo and IG-W alloys.

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“…Um exemplo de codeposição induzida são as ligas de W com os elementos Ni, Co, e Fe 7,8 . Muitos autores investigaram o processo de eletrodeposição do tungstênio com os metais do grupo do ferro em soluções aquosas 9,10 . O metal tungstênio e suas ligas são utilizados em situações que necessitam de altas temperaturas.…”

Section: Introductionunclassified

Otimização do banho eletrolítico da liga Fe-W-B resistente à corrosão

Santana¹,

Campos²,

Prasad³

et al. 2007

Quím. Nova

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Recebido em 2/2/06; aceito em 12/6/06; publicado na web em 28/11/06 OPTIMIZATION OF THE ELECTROLYTIC BATH FOR ELECTRODEPOSITION OF CORROSION RESISTANT Fe-W-B ALLOYS. A study on optimization of bath parameters for electrodeposition of Fe-W-B alloys from plating baths containing ammonia and citrate is reported. A 2 3 full factorial design was successfully employed for experimental design analysis of the results. The corrosion resistance and amorphous character were evaluated. The bath conditions obtained for depositing the alloy with good corrosion resistance were: 0.01 M iron sulfate, 0.10 M sodium tungstate and 0.60 M ammonium citrate. The alloy was deposited at 12% current efficiency. The alloy obtained had Ecorr -0.841 V and Rp 1.463 x 10 4 Ohm cm 2 . The deposit obtained under these conditions had an amorphous character and no microcracks were observed on its surface. Besides this, the bath conditions obtained for depositing the alloy with the highest deposition efficiency were: 0.09 M iron sulfate, 0.30 M sodium tungstate and 0.50 M ammonium citrate. The alloy was deposited at 50% current efficiency, with an average composition of 34 wt% W, 66 wt% Fe and traces of boron. The alloy obtained had Ecorr -0.800 V and Rp 1.895 x 10 3 Ohm cm 2 . Electrochemical corrosion tests verified that the Fe-W-B alloy deposited under both conditions had better corrosion resistance than Fe-Mo-B.Keywords: Fe-W-B alloy; electrodeposition; corrosion resistance. INTRODUÇÃOOs revestimentos protetores, além de constituírem uma importante forma de prevenção à corrosão metálica, principalmente a atmosférica, podem melhorar consideravelmente as propriedades fí-sico-químicas das superfícies. Os revestimentos mais comuns são os de cobre, níquel e cromo 1 . A eletrodeposição representa uma boa maneira de revestir as superfícies metálicas 2,3 ; uma das aplicações industriais mais importantes da eletrodeposição é o revestimento com finalidade de inibir a corrosão, que ocorre na superfície do metal e nas suas estruturas sob influência do meio ambiente 4,5 . O termo "codeposição induzida" foi apresentado por Brenner para descrever uma situação em que um metal não pode ser eletrodepositado a partir de solução aquosa na sua forma pura e sim, codepositado na presença de outro metal, formando dessa forma uma liga 6 . Um exemplo de codeposição induzida são as ligas de W com os elementos Ni, Co, e Fe 7,8 . Muitos autores investigaram o processo de eletrodeposição do tungstênio com os metais do grupo do ferro em soluções aquosas 9,10 . O metal tungstênio e suas ligas são utilizados em situações que necessitam de altas temperaturas. O tungstênio apresenta as seguintes propriedades: alta resistência à corrosão, dureza, mesmo em temperaturas elevadas, baixo coeficiente de dilatação, alta condutividade térmica, além de não ser atacado por nenhum ácido mineral à temperatura ambiente 11 e forma ligas duras com o cobalto, retendo algumas de suas propriedades incomuns 1 . O planejamento fatorial experimental apresenta muitas vantagens sobre os métodos univa...

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Codeposition of Tungsten and Nickel from an Aqueous Ammoniacal Citrate Bath

Cited by 37 publications

References 0 publications

Electrolytic Reduction of Aqueous Tungstate Solutions

Electrolytic Reduction of Aqueous Tungstate Solutions

Aqueous Electrodeposition and Mechanism of Iron Group-Vanadium Ternary Alloys

Otimização do banho eletrolítico da liga Fe-W-B resistente à corrosão

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