Control and optimization of baths for electrodeposition of Co-Mo-B amorphous alloys

Prasad, Shiva; Marinho, Fabiano A.; Santana, François Sandini Marques De

doi:10.1590/s0104-66322000000400007

Cited by 16 publications

(14 citation statements)

References 12 publications

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“…They have argued that NaH 2 PO 2 acts as an accelerator that changes the kinetics of Co and Mo codeposition . Prasad et al have claimed that Co–Mo–B coatings obtained from citrate based baths are found to have interesting properties such as high hardness, corrosion resistance, wear resistance and also sufficient ductility . Balaraju et al have obtained Ni–W–P alloy coatings by electroless deposition and found that ternary Ni–W–P deposits have shown higher hardness values compared to binary Ni–W deposits .…”

Section: Introductionmentioning

confidence: 99%

Effect of P codeposition on the structure and microhardness of Co–W coatings electrodeposited from gluconate bath

Seenivasan

Bera

2016

Surface & Interface Analysis

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Effects of addition of P to Co-W coatings from gluconate bath using direct current (DC) and pulse current (PC) methods have been investigated in this study. Co-W-P coatings with different P concentrations are prepared by varying hypophosphite concentration in the bath. Current efficiency of the Co-W-P electrodeposition is lower than that for Co-W coatings. Increase in NaH 2 PO 2 concentration increases the cobalt content significantly and decreases the tungsten content drastically. Co-W-P coatings display 'cauliflower-like' morphology and roughness of the coatings increases with increasing P content. As-deposited Co-W-P deposits are amorphous while heat treatment at different temperatures has rendered them crystalline with the precipitation of stable species like, Co 3 W, Co 2 P, etc. Unlike Co-W coatings, Co-W-P shows two-step crystallization in differential scanning calorimetry (DSC) and on heat treatment, which is similar to the behavior of Co-P electrodeposited from gluconate baths. Moreover, inclusion of phosphorous and heat treatment have led to significant increase in microhardness of the Co-W-P coatings. X-ray photoelectron spectroscopy (XPS) studies provide a detailed insight into the nature of Co, W and P species in as-deposited and sputtered coatings. Microhardness of the heat-treated coatings is higher than the as-deposited counterparts and is comparable with that of hard chromium.

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Section: Introductionmentioning

confidence: 99%

Effect of P codeposition on the structure and microhardness of Co–W coatings electrodeposited from gluconate bath

Seenivasan

Bera

2016

Surface & Interface Analysis

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“…O objetivo principal da MSR é determinar as condições ótimas de operação para um sistema ou determinar uma região que satisfaça as especificações operacionais 13 . Para dar continuidade aos trabalhos que estão sendo desenvolvidos no Laboratório de Eletroquímica e Eletroanalítica da Universidade Federal de Campina Grande [14][15][16][17] , este trabalho deu ênfase ao processo de otimização do banho eletrolítico para eletrodeposição da liga de Fe-W-B em função da sua eficiência de deposição e resistência à corrosão . Foi usada a metodologia de superfície de resposta para auxiliar no processo de otimização.…”

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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“…But no experimental difficulty is experienced in codepositing tungsten with the group 8 metals. Several authors have investigated the process of electrodeposition of tungsten with iron group metals in aqueous solutions [2][3][4][5][6]. It is well known that alloys such as Co-W-B and Ni-W-B are characterized by high surface hardness; Vickers hardness values between 450 and 650 kgf mm )2 have been reported for these coatings in the as-deposited condition [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition and corrosion behaviour of a Ni–W–B amorphous alloy

et al. 2005

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Electrodeposition of Ni-W-B alloys from plating baths containing ammonia and citrate is reported. Optimum conditions for plating including current density, temperature, mechanical agitation and pH were studied. The corrosion resistance and amorphous character were also evaluated. The operational conditions for depositing the alloy with good corrosion resistance were: current density 35 mA cm )2 , bath temperature 40°C, pH 9.0 and cathode rotation at 90 rpm. The alloy was deposited at 38% current efficiency, with an average composition of 73 wt% Ni, 27 wt% W and traces of boron and with E corr )0.300 V and R p 3.369Â10 4 W. The deposit obtained under these conditions had an amorphous character with the presence of some microcracks on its surface reaching down to the copper substrate. Electrochemical corrosion tests verified that the Ni-W-B alloy had better corrosion resistance than Co-W-B.

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Control and optimization of baths for electrodeposition of Co-Mo-B amorphous alloys

Cited by 16 publications

References 12 publications

Effect of P codeposition on the structure and microhardness of Co–W coatings electrodeposited from gluconate bath

Effect of P codeposition on the structure and microhardness of Co–W coatings electrodeposited from gluconate bath

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

Electrodeposition and corrosion behaviour of a Ni–W–B amorphous alloy

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