Composite and Composite Coatings

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.

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Chemical deposition of hard composite coatings Ni–Cu–P–Cr2O3

10.36652/1813-1336-2020-16-4-179-181 ◽

2020 ◽

pp. 179-181

Author(s):

A.A. Abrashov A.A. ◽

E.G. Vinokurov ◽

M.A. Egupova ◽

V.D. Skopintsev

Keyword(s):

Chromium Oxide ◽

Alkaline Solution ◽

Composite Coatings ◽

Chemical Deposition ◽

Alkaline Solutions ◽

Functional Surface ◽

Heat Treated ◽

Weakly Acid Solution ◽

Coating Composition ◽

Weakly Acidic Solution

The technological (deposition rate, coating composition) and functional (surface roughness, microhardness) characteristics of chemical composite coatings Ni—Cu—P—Cr2O3 obtained from weakly acidic and slightly alkaline solutions are compared. It is shown that coatings deposited from slightly alkaline solution contain slightly less phosphorus and chromium oxide than coatings deposited from weakly acid solution (2...3 % wt. phosphorus and up to 3.4 % wt. chromium oxide), formed at higher rate (24...25 microns per 1 hour of deposition at temperature of 80 °C), are characte rized by lower roughness and increased microhardness. The Vickers microhardness at 0.05 N load of composite coatings obtained from slightly alkaline solution and heat-treated at 400 °C for 1 hour is 13.5...15.2 GPa, which is higher than values for coatings deposited made of weakly acidic solution. The maximum microhardness of coatings is achieved at concentration 20 g/l of Cr2O3 particles. The technology of chemical deposition of Ni—Cu—P—Cr2O3 coatings formed in slightly alkaline solution is promising for obtaining of materials with increased hardness and wear resistance.

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Thermochemical and Thermomechanical study on Composite Coatings (Al 2O 3+ZrO 2•5CaO)

SSRN Electronic Journal ◽

10.2139/ssrn.3511933 ◽

2019 ◽

Author(s):

Abhinav T ◽

N. Krishna Murthy ◽

Avinash J Nair

Keyword(s):

Composite Coatings

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Preparation of MCrAlY–Al2O3 Composite Coatings with Enhanced Oxidation Resistance through a Novel Powder Manufacturing Process

Journal of Thermal Spray Technology ◽

10.1007/s11666-019-00830-y ◽

2019 ◽

Vol 28 (3) ◽

pp. 433-443 ◽

Cited By ~ 9

Author(s):

Mingwen Bai ◽

Bo Song ◽

Liam Reddy ◽

Tanvir Hussain

Keyword(s):

Oxidation Resistance ◽

Manufacturing Process ◽

Composite Powder ◽

Composite Coatings ◽

Submicron Particles ◽

Second Phase ◽

Mcraly Coatings ◽

Powder Feedstock ◽

Enhanced Oxidation ◽

Powder Manufacturing

Abstract MCrAlY–Al2O3 composite coatings were prepared by high-velocity oxygen fuel thermal spraying with bespoke composite powder feedstock for high-temperature applications. Powder processing via a suspension route was employed to achieve a fine dispersion of α-Al2O3 submicron particles on the MCrAlY powder surface. This was, however, compromised by ~ 50% less flowability of the feedstock during spraying. Nevertheless, the novel powder manufacturing process introduced in this study has shown potential as an alternative route to prepare tailored composite powder feedstock for the production of metal matrix composites. In addition, the newly developed MCrAlY–Al2O3 composite coatings exhibited superior oxidation resistance, compared to conventional MCrAlY coatings, with the formation of nearly exclusively Al2O3 scale after isothermal oxidation at 900 °C for 10 h. The addition of α-Al2O3 particles in the MCrAlY coatings as a second phase was found to have promoted the formation of YAG oxides (YxAlyOz) during spraying and also accelerated the outwards diffusion of Al, which resulted in enhanced oxidation resistance.

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