BLACK Ni-BASED GALVANIC COATINGS

Shcherbina, Ekaterina; Abrashov, A. A.; Grigoryan, N. S.; Vagramyan, T. A.; Menshikov, Vladimir

doi:10.37904/metal.2019.901

Cited by 2 publications

(1 citation statement)

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“…According to the results of the study were obtained survey spectra of coatings, which were decomposed into the constituent spectra of the elements after subtracting the background [9,10].…”

Section: Methodsmentioning

confidence: 99%

Low-temperature deposition process for black phosphate-selenide coatings

Aleshina¹,

Abrashov²,

Grigoryan³

et al. 2021

cisisr

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Oxide coatings are widely used as protective and decorative coatings on ferrous metals under non-harsh operating conditions. For protective and decorative oxidation, a chemical oxidation method is widely used using concentrated alkaline solutions (600-800 g/l NaOH) operating at very high temperatures (130-150 °C). The obvious disadvantages of the process are the high energy consumption, difficult working conditions, the aggressiveness of the solutions used and low protective ability of the coatings due to their high porosity. In addition, it is known that to harden the surfaces of machine parts in order to increase wear resistance, they are thermally laser treated. The surface hardening is the more effective, the higher the absorption coefficient of the treated surface. For laser heat treatment, high-temperature (95-98 °C) processes of applying black phosphate coatings with a high absorption coefficient (0.8-0.9) are used. The disadvantages of these processes are also the instability of solutions and the irreproducibility of the results. This work is about to the study of the process of formation of phosphate-selenide coatings on steel in order to replace high-temperature solutions of black oxidation and phosphating. A low-temperature process has been developed for the deposition of black selenide-containing phosphate coatings on steel, corresponding to a point of 10 on a ten-point color scale, in a solution containing: 4-8 g/l Na 2 SeO 3 ; 1-4 g/l CuSO 4 ⋅5H 2 O; 0.5-5 g/l NaH 2 PO 4 and 0.25-2.5 g/l Na 2 HPO 4 ([NaH 2 PO 4 ]/[Na 2 HPO 4 ] molar ratio is 2); 5 min at pH = 2-3, t = 18-25 °C. Oiling the coatings in I-20A industrial oil for 2 min leads to an increase in the protective ability of the coatings according to Akimov from 1 to 25 min. Corrosion tests of coatings in a salt spray chamber in accordance with ASTM B117 have shown that oiled phosphate-selenide coatings have the greatest protective ability: the first spots of red corrosion appear after 20 hours of testing, while oxidized, oiled samples begin to corrode after 18 hours. After 100 hours of testing, the area of the oxidized sample affected by corrosion is 90 %, and the oiled phosphated sample is 50.

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“…According to the results of the study were obtained survey spectra of coatings, which were decomposed into the constituent spectra of the elements after subtracting the background [9,10].…”

Section: Methodsmentioning

confidence: 99%

Low-temperature deposition process for black phosphate-selenide coatings

Aleshina¹,

Abrashov²,

Grigoryan³

et al. 2021

cisisr

View full text Add to dashboard Cite

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Black Nickel Coatings: From Plating Techniques to Applications

Rudnik

2024

Coatings

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Black nickel coatings are pursued for both decorative purposes and advanced applications, including solar collectors, space technologies, and optical devices. The term “black nickel” typically refers not only to nickel but also to nickel alloys that can exhibit the characteristic black coloration, either bright or matte. This review provides an in-depth look at various techniques for producing black nickel coatings, focusing on both electrodeposition and electroless deposition methods. The discussion covers the different bath compositions and deposition conditions used to achieve the distinctive black color. The origins of black coloration in electrodeposited nickel and its alloys are shown in detail, emphasizing the crucial role of bath components and the formation of black compounds such as oxides, sulfides, and/or the nickel–zinc intermetallic compound. This review also highlights the necessity of oxidizing acid etching to blacken Ni–P electroless deposits, leading to the formation of a thin layer of black nickel oxides on a porous surface. The key properties of black nickel coatings are discussed, along with their relevance for various practical applications.

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BLACK Ni-BASED GALVANIC COATINGS

Cited by 2 publications

References 0 publications

Low-temperature deposition process for black phosphate-selenide coatings

Low-temperature deposition process for black phosphate-selenide coatings

Black Nickel Coatings: From Plating Techniques to Applications

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