Electrodeposition of Thick Chromium Coatings from an Environmentally Acceptable Chromium (III)-Glycine Complex

El‐Sharif, M.; McDougall, J. L.; Chisholm, C. U.

doi:10.1080/00202967.1999.11871269

Cited by 52 publications

(36 citation statements)

References 16 publications

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“…The working lifetime of the electrolyte containing HCOONa alone is very short and the maximum thickness of Cr coating is about 2-3 lm, whereas a thick coating (about 30lm) of good quality may be obtained in bath containing the optimum concentrations of both formate and urea. It is known [6] 5 ] 2+ ions and HCOO ) . Accumulation of Cr(II) particles (catalysts for an olation reaction) in the diffusion layer may be responsible for collapse of the deposition rate.…”

Section: Resultsmentioning

confidence: 99%

“…Anions that easily enter into the co-coordinated sphere and displace OH ) groups can effectively prevent olation [8]. Some of organic ligands influence the plating rate and the quality of the coatings due to the formation of Cr(III) active complexes [1][2][3][4][5]. However, the reasons why thick chromium coatings are difficult to obtain in Cr(III) baths have not been fully clarified.…”

Section: Introductionmentioning

confidence: 99%

“…To destabilize the strong hexa-aqua chromium(III) complex some of the complexing agents (formic acid, urea, acetate, glycine, etc.) may be used [1][2][3][4][5][6][7]. The most important fact is that Cr(III) does not oxidize organic compounds.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Cr(III) solution chemistry on electrodeposition of chromium

Surviliene¹,

Nivinskienė²,

Češūnienė³

et al. 2006

J Appl Electrochem

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This work provides a new insight into the interaction of urea with formate during the chromium electrodeposition from a sulphate-based Cr(III) solution. The influence of solution chemistry on chromium electrodeposition in a Cr(III) bath containing sodium formate and urea as complexing agents was studied by FT-IR, XPS and AFM. The results show that good quality Cr coatings may be obtained only in those cases when the secondary ligand with the carbamidic group predominates over urea in the electrolyte. This suggests that electrodeposition of good quality chromium deposit is possible due to the formation of active chromium-carbamid complexes [Cr(carbamid) n (H 2 O) 6-n ] 3+ . These complexes delay the formation of the stable oligomeric species, and thus provide a prolonged working lifetime in the Cr(III) formate-urea electrolyte.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Cr(III) solution chemistry on electrodeposition of chromium

Surviliene¹,

Nivinskienė²,

Češūnienė³

et al. 2006

J Appl Electrochem

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“…It was found that improvement could be achieved when glycine (H 2 N-CH 2 -COOH) is added to an electrolyte containing polyoxialkylene (PEG or PPG) [12]. However, it is believed, that ammonium ions are necessary to achieve adequate interaction of Cr(III) with glycine [10,13]. The mechanism of the effect of ammonium ions during the Zn-Cr co-deposition is not clear yet.…”

Section: Introductionmentioning

confidence: 99%

Deposition of Zn–Cr alloy coatings from sulfate electrolyte: effect of polypropylene glycol 620 and glycine and combinations thereof

et al. 2008

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The effect of polypropylene glycol with molecular mass 620 (PPG 620) and glycine as additives in electrodeposition of Zn-Cr alloy coatings from acidic sulfate electrolyte containing (NH 4 ) 2 SO 4 and H 3 BO 3 , at ambient temperature, without agitation is investigated. PPG 620 inhibits the Zn reaction causing significant proximity of the deposition potentials of Zn and Cr, and a co-deposition at a less negative potential of -1.8 V (vs. Hg/Hg 2 SO 4 ) as compared to the case when polyethylene glycol 1500 (PEG 1500) is used. Depending on the deposition conditions, alloy coatings containing up to 23 mass % Cr can be obtained. Glycine itself does not facilitate the co-deposition of Cr and Zn. Added to the electrolyte containing PPG 620, glycine causes a decrease of the Cr content in the alloy. However, the alloy coatings deposited in the presence of both additives are denser, have better overall appearance and good adherence to the steel substrate. Moreover, glycine increases the buffer capacity of the electrolyte. At short deposition times, the alloy coatings consist mainly of bcc C x -(Zn, Cr) phase with lattice parameter about 3.035 (3) Å and mean crystallite size of the order of 25 nm. Cr content in the coatings can be controlled by changing the concentration of Cr(III) and pH of the electrolyte as well as the current density. Depending on the working conditions, the cathode current efficiency is within 35-55%.

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“…So far, the development of different coatings on steel through electrodeposition has been investigated, such as Zn coating, Ni coating and Cr coating, and they appeared to provide corrosion resistance to various degrees in air and a range of gaseous environments (Moniruzzaman and Roy, 2011;Ou et al, 2008;Steffani et al, 1997;Trethewey and Chamberlain, 1995). Electrodeposited Cr is widely used as the outer surface of precision parts due to its attractive appearance and superior corrosion resistance (Brooman, 1994;El-Sharif et al, 1999;Brooman et al, 1994). Until now, Cr deposits were commonly obtained using an electroplating bath with hexavalent Cr ions.…”

Section: Introductionmentioning

confidence: 99%

Cr-Ni Alloy Electrodeposition and Comparison with Conventional Pure Cr Coating Technique

Moniruzzaman¹,

Rakib²,

Matin³

2012

Int J Automot Mech Eng

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Cr coating is widely used as the outer surface of precision parts due to its attractive appearance and superior corrosion resistance properties. It is obtained by electrodeposition via a conventional bath with hexavalent Cr ions. This manufacturing technique has many drawbacks, such as very low efficiency and high operating temperature and it is hazardous to health. In this work, we studied a Cr-Ni alloy deposition technique and compared the alloy coating properties to those with conventional Cr coating. Sequential two-step alloy electrodeposition was also compared. We took varying concentrations of Cr, Ni and complexing agents for the electrodeposition of Cr-Ni alloy and sequential Cr-Ni alloy coating on mild steel. Operating parameters, i.e. current density and temperature, were varied to examine their effects on the coating properties. The coatings thus obtained were characterized by visual observation, corrosion test, microhardness measurement, morphology and chemical analysis. The Cr-Ni alloy coating was found to be more corrosion resistant in 5% NaCl solution and harder than the pure Cr coating obtained by conventional electrodeposition. Toxic gas was produced in a much lower extent in the alloy coating than the conventional Cr coating technique. Again, the two-step Cr-Ni alloy coating was found better in terms of corrosion resistance as well as hardness compared to the Cr-Ni alloy coating. The process was also found to be much more environmentally friendly.

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Electrodeposition of Thick Chromium Coatings from an Environmentally Acceptable Chromium (III)-Glycine Complex

Cited by 52 publications

References 16 publications

Effect of Cr(III) solution chemistry on electrodeposition of chromium

Effect of Cr(III) solution chemistry on electrodeposition of chromium

Deposition of Zn–Cr alloy coatings from sulfate electrolyte: effect of polypropylene glycol 620 and glycine and combinations thereof

Cr-Ni Alloy Electrodeposition and Comparison with Conventional Pure Cr Coating Technique

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