Plating on magnesium alloy diecastings

Dennis, J.K.; Wan, Maoyuan; Wake, S.

doi:10.1080/00202967.1985.11870711

Cited by 19 publications

(5 citation statements)

References 6 publications

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“…Huang et al [11] proposed a environment-friendly pretreatment with galvanostatic etching to obtain an adherent and uniformly covered copper deposit on pure Mg and Mg alloys of AZ31 and AZ61 in the alkaline Cu sulfate plating bath. Dennis et al [12,13] studied the effects of three proprietary pretreatment sequences, i.e., the Dow process, the Norsk-Hydro process and the WCM canning process on various Mg alloy diecasts, e.g. AZ91CC (Cold Chamber), AZ61CC, AZ91HC (Hot Chamber) and AZ71HC.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, metal electroplating is performed by the following processes: surface cleaning, acid pickling, activation, zincating, and metal electrodeposition. However, highly toxic chromic acid has sometimes been used in the acid pickling process, and poisonous cyanide has also sometimes been used in Cu electrodeposition to improve the adhesion strength of Cu layer to the Mg alloy substrate [12][13][14]. Moreover, zincate pretreatment has been carried out at 70-80 °C, temperatures at which the composition of the zincate bath may change due to rapid water evaporation, resulting in low reproducibility of pretreatment for an Mg alloy.…”

Section: Introductionmentioning

confidence: 99%

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Influence of zincate pretreatment on adhesion strength of a copper electroplating layer on AZ91 D magnesium alloy

Tang

Azumi

2011

Surface and Coatings Technology

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Cu was electrodeposited on AZ91 D Mg alloy with zincate pretreatment in an alkaline plating bath, and the effect of zincate pretreatment on adhesion strength of the Cu layer was investigated. Scanning electron microscopy results showed that Zn was mainly deposited on the α-phase surface, and ultrasonic agitation at the initial stage of the zincate pretreatment improved the coverage of the Zn layer even on the β-phase surface, resulting in enhancement of the adhesion strength of the Zn layer and the successive Cu layer to the substrate.Adhesion tests revealed that the plating layer peeled off at the mixed layer of Zn and Cu deposits formed at the interface between the zincated layer and the electrodeposited Cu layer.A smooth Cu surface was obtained in the plating bath containing H 3 BO 3 .

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of zincate pretreatment on adhesion strength of a copper electroplating layer on AZ91 D magnesium alloy

Tang

Azumi

2011

Surface and Coatings Technology

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“…Despite these difficulties, electroplating can provide potentially uniform coatings with good corrosion resistance for Mg alloys by using zincate pretreatment. [6][7][8][9][10][11] Application of zincate pretreatment to Mg alloys, however, has sometimes resulted in non-uniform Zn deposition, probably due to non-uniform dissolution of the substrate during the zincate process. 11 In the case of Al and its alloys, zincate pretreatment has also been optimized to obtain uniform Zn deposition.…”

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confidence: 99%

Effect of Copper Pretreatment on the Zincate Process and Subsequent Copper Electrodeposition of AZ31 Magnesium Alloy

Tang

Azumi

2011

J. Electrochem. Soc.

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A small amount of Cu 2þ ions was added to the activation bath used for pretreatment of the plating process of an AZ31 Mg alloy. In the activation process, a small amount of Cu was deposited at high density on the substrate surface accompanying Mg dissolution (Cu pretreatment). These Cu deposits acted as nucleation seeds for Zn deposition in the following zincate process and provided a uniform and dense Zn layer almost completely covering the substrate. The Cu layer electroplated on this zincated substrate showed considerable improvement in density and uniformity compared with those of the sample without Cu pretreatment. Crosssectional SEM observation revealed that a less-defective interface between the Cu layer and substrate was obtained for the Cu-prepared sample. This structure also contributed to the improvement of adhesion strength. The mechanism of this improvement was investigated using electrochemical measurement and scanning electron microscopy observation with energy dispersive X-ray spectroscopy analysis. Owing to their superior strength, light weight and rich natural resources, Mg and its alloys are attractive materials in various applications. Unfortunately, the surface of Mg is easily covered with a thick oxide or hydroxide layer with a high electric resistance, which may not be suitable for some applications such as electronic devices. Therefore, it is important to establish a plating method that can produce functional coatings on Mg alloys such as corrosion-resistant and electrically conductive coatings with sufficient adhesivity.Since a thick passivation film is formed on Mg under an ambient atmosphere, pretreatment is necessary to remove the surface layer and to suppress its reformation prior to the plating process. [1][2][3][4][5] It is also important to obtain a uniform surface condition on Mg alloys for plating because intermetallic compounds such as Mg x Al y are formed at grain boundaries. Despite these difficulties, electroplating can provide potentially uniform coatings with good corrosion resistance for Mg alloys by using zincate pretreatment.6-11 Application of zincate pretreatment to Mg alloys, however, has sometimes resulted in non-uniform Zn deposition, probably due to non-uniform dissolution of the substrate during the zincate process.11 In the case of Al and its alloys, zincate pretreatment has also been optimized to obtain uniform Zn deposition. The effectiveness of various methods for reducing the influence of intermetallic compounds of Al alloys in an electroless plating process has been studied. These methods include etching treatment, 12 formation of a seed layer by using a dry process, 13-17 and other techniques. Our group previously reported that addition of a small amount of Cu ions to the etching bath can dramatically improve the uniformity of Zn deposits on Al-Si alloys in the double zincate process because Cu deposits formed in the etching process acted as nucleation seeds for Zn deposition (Cu pretreatment).18 Since Cu pretreatment was effective for obtaining uniform Zn...

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“…With typical high-phosphorus applications, 4 MTO is the maximum bath life. The need to extend the operational life of EN solutions, or even to operate these endlessly, is probably as old as the technology itself.Different from the commonly used EN process on steel and aluminum alloys, the EN process on magnesium alloys has a unique formula [4][5][6][7]. It was found that nickel chloride and nickel sulphate may not be used as the source of nickel ions in the EN bath for magnesium alloys.…”

mentioning

confidence: 99%

“…Different from the commonly used EN process on steel and aluminum alloys, the EN process on magnesium alloys has a unique formula [4][5][6][7]. It was found that nickel chloride and nickel sulphate may not be used as the source of nickel ions in the EN bath for magnesium alloys.…”

mentioning

confidence: 99%

Reconditioning of Electroless Nickel Plating Bath on Magnesium Alloys

Liu

Xiang

et al. 2011

MSF

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The reconditioning operation of electroless nickel (EN) plating was studied and the influence of aging on the deposition speed, phosphorous content and stability of the operating solution was analyzed. The results showed that aging of the EN bath caused a dramatic declining of the deposition speed and the bath stability, while a slow increasing in phosphorous content of the deposit. Fluoride of NaF and NiF2would precipitate from the bath due to the accumulation of sodium and fluorine ions during the replenishment. The sediment of NaF and NiF2had a detrimental effect on the EN process and would deteriorate the protection of EN plating.

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Plating on magnesium alloy diecastings

Cited by 19 publications

References 6 publications

Influence of zincate pretreatment on adhesion strength of a copper electroplating layer on AZ91 D magnesium alloy

Influence of zincate pretreatment on adhesion strength of a copper electroplating layer on AZ91 D magnesium alloy

Effect of Copper Pretreatment on the Zincate Process and Subsequent Copper Electrodeposition of AZ31 Magnesium Alloy

Reconditioning of Electroless Nickel Plating Bath on Magnesium Alloys

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