Electrochemical characterisation of the porosity and corrosion resistance of electrochemically deposited metal coatings

Walsh, Frank C.; León, Carlos Ponce de; Kerr, Charles; Court, S.; Barker, B.D.

doi:10.1016/j.surfcoat.2008.05.008

Cited by 109 publications

(43 citation statements)

References 24 publications

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“…Neutral chemical porosity tests were carried out to evaluate the coating porosity of the samples. An aqueous solution of red potassium prussiate was adopted as ferroxyl indicator [20,26]. The corrosive solution attacked the substrate through the pores during the test.…”

Section: Microstructure Analyses and Porosity Measurementsmentioning

confidence: 99%

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Corrosion Resistance Of Electroless Ni-P/Cu/Ni-P Multilayer Coatings

Zhao

Zou

Hao

et al. 2015

Archives of Metallurgy and Materials

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coatings were prepared by deposition of Cu layer between two Ni-P layers. The Cu layer was deposited by metal displacement reaction between Cu 2+ and Fe atoms. Corrosion behavior of single-layer Ni-P coatings, double-layer Ni-P/Cu coatings, and three-layer Ni-P/Cu/Ni-P coatings were investigated by electrochemical tests in 3.5% NaCl solution. The three-layer coatings exhibited more positive E corr and decreased I corr compared with conventional single-layer Ni-P coatings, which indicated an improved corrosion resistance. The polarization curves of the three-layer coatings were characterized by two passive regions. The improved corrosion resistance was not only attributed to the function of the blocked pores of Cu. The Cu interlayer also acted as a sacrificial layer instead of a barrier in the coatings, which altered the corrosion mechanism and further improved the corrosion resistance of the coatings.Keywords: electroless plating, multilayer coatings, porosity, electrochemical tests, crystalline Cu layerWielowarstwowe powłoki Ni-P/Cu/Ni-P wytworzono metodą osadzania miedzi pomiędzy dwoma warstwami Ni-P. Warstwę Cu otrzymano dzięki reakcji wypierania metalu przez metal (dla miedzi i żelaza). Aby określić właściwości korozyjne jednowarstwowej powłoki Ni-P, dwuwarstwowej Ni-P/Cu oraz trójwarstwowej Ni-P/Cu/Ni-P przeprowadzono pomiary elektrochemiczne w 3,5% roztworze NaCl. Powłoki trójwarstwowe w porównaniu do jednowarstwowych wykazały się większą wartością E corr , przy malejącej wartości I corr . Wskazuje to na poprawę odporności na korozję. Krzywe polaryzacji dla powłok trójwarstwowych charakteryzują się występowaniem dwóch obszarów pasywacji. Poprawa odporności na korozję jest skutkiem nie tylko tzw. zjawiska blokowania porów w miedzi. Powłoka z Cu działała także jako warstwa protektorowa, modyfikując mechanizm korozji i poprawiając odporność korozyjną powłok.

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Section: Microstructure Analyses and Porosity Measurementsmentioning

confidence: 99%

“…Adsorption of gas bubbles results in isolation of these locations from the plating bath and formation of coating defects [19][20][21]. In this study, a Cu interlayer was sandwiched by two Ni-P layers to block the holes in the coating.…”

Section: Introductionmentioning

confidence: 97%

Corrosion Resistance Of Electroless Ni-P/Cu/Ni-P Multilayer Coatings

Zhao

Zou

Hao

et al. 2015

Archives of Metallurgy and Materials

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“…The degree of corrosion of the basic material under protective coating is determined by the quantity and size of the surface defects, as well as the coating thickness 33) . The release of the Ni 2+ and Ti 4+ ions should be attributed to the pores found in disrupted surface coating 2,3) , and the variability in ion release should be attributed to greater variations in surface coating thickness and homogeneity between the specimens.…”

Section: Discussionmentioning

confidence: 99%

Effect of pH, fluoride and hydrofluoric acid concentration on ion release from NiTi wires with various coatings

Katić

Ćurković

Bošnjak³

et al. 2017

Dent. Mater. J.

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Aim was to determine effect of pH, fluoride (F − ) and hydrofluoric acid concentration (HF) on dynamic of nickel (Ni 2+ ) and titanium (Ti 4+ ) ions release. Nickel-titanium wires with untreated surface (NiTi), rhodium (RhNiTi) and nitride (NNiTi) coating were immersed once a week for five min in remineralizing agents, followed by immersion to artificial saliva. Ion release was recorded after 3, 7, 14, 21 and 28 days. Pearson correlations and linear regression were used for statistical analysis. Release of Ni 2+ from NiTi and NNiTi wires correlated highly linearly positively with HF (r=0.948 and 0.940, respectively); for RhNiTi the correlation was lower and negative (r=−0.605; p<0.05). The prediction of Ti 4+ release was significant for NiTi (r=0.797) and NNiTi (r=0.788; p<0.05) wire. Association with F − was lower; for pH it was not significant. HF predicts the release of ions from the NiTi wires better than the pH and F − of the prophylactic agents.

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“…Walsh et al [71] investigated the influence of the porosity of electrochemically deposited metal coatings on the corrosion properties of the specimen. Fig.…”

Section: Electroplatingmentioning

confidence: 99%

“…6 indicates a rapid decrease of the corrosion rate of nickel coatings on aluminum with increasing thickness of the layer. From a thickness of ~2.5 µm a horizontal region indicates a pore free passive film [71]. Hental et al [29] coated an aluminum substrate material with gold.…”

Section: Electroplatingmentioning

confidence: 99%