Investigation of Internal Stresses in Thin Layer Oxide Coatings on Aluminum Alloys

2019 ◽  
Vol 968 ◽  
pp. 153-160 ◽  
Author(s):  
Yuri A. Kuznetsov ◽  
Aleksandr V. Kolomeichenko ◽  
Vladimir V. Goncharenko ◽  
Igor N. Kravchenko
Keyword(s):  
External Action ◽  
Ceramic Coatings ◽  
Experimental Investigations ◽  
Internal Stresses ◽  
Oxide Ceramic ◽  
Oxide Coatings ◽  
Properties Of Coatings ◽  
Oxide Ceramic Coatings ◽  
Plasma Electrolytic ◽  
Aluminum Surfaces

Among physical and mechanic properties of coatings the internal stresses are of special interest. Internal stresses include stresses which exist and are counterbalanced within a rigid body in cases when there is no external action which caused them. In coatings obtained on the basis of nickel, chrome they can decrease the adhesive strength, cause cracking, peeling, anticorrosion properties deterioration. But the definite level of internal stresses leads to increase of hardness and coatings wear resistance and also facilitates porous coatings obtaining. The results of theoretical and experimental investigations of the internal stresses that appear in oxide ceramic coatings formed by plasma-electrolytic oxidation (PEO) on aluminum surfaces are presented.

Electrochemical Characteristics of PEO Treated Electric Arc Coatings on Lightweight Alloys

2010 ◽  
Vol 138 ◽  
pp. 55-62 ◽  
Author(s):  
H.M. Nykyforchyn ◽  
V.I. Pokhmurskii ◽  
M.D. Klapkiv ◽  
Mykhajlo M. Student ◽  
Juliet Ippolito
Keyword(s):  
Corrosion Resistance ◽  
Ceramic Coatings ◽  
Electric Arc ◽  
Arc Spraying ◽  
Oxide Ceramic ◽  
Electrochemical Characteristics ◽  
Ti Alloys ◽  
Oxide Phases ◽  
Oxide Ceramic Coatings ◽  
Plasma Electrolytic

The complex technology of the surface treatment of Al, Mg, Ti alloys for size reconstruction and strengthening is presented herein. This consists of electric arc spraying of aluminum alloys or powder wire in an aluminum shell and then treatment with plasma electrolytic oxidation (PEO). Once treated, oxide-ceramic coatings maintain extreme hardness, durability and resistance to wear. At the same time their corrosion-resistant properties are also significant. Dynamic potential dependences were studied for electric arc Al coatings and PEO treatments on Al, Mg, Ti alloys and corrosion currents were analyzed for exposure to a corrosive environment for a period of from 1 hour to 30 days. It was established that PEO treated coatings on Al alloys have a higher corrosion resistance than untreated sprayed coatings. In Mg alloys, an intermediate layer of aluminum electric arc coating between the substrate and PEO-treated coating is necessary in order to ensure high corrosion resistance. This is due to the specifics of the formation of the MgO and Al2O3 oxide phases in the plasma discharge channels. At the same time Al coatings on Ti alloys, including those of post-PEO treatment, were characterized as having lower corrosion resistance within the range of electrode potential from corrosion potential up to repassivation potential, than were untreated Ti-alloys. Yet it was found that the corrosion resistance of PEO treated coatings increases at higher anode potentials. Under cathode polarization the hydrogen discharge is less likely to occur on PEO-coatings than on untreated Ti alloys which more effectively prevents hydrogenation.

scholarly journals Introduction to Plasma Electrolytic Oxidation—An Overview of the Process and Applications

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 628 ◽  
Author(s):  
Frank Simchen ◽  
Maximilian Sieber ◽  
Alexander Kopp ◽  
Thomas Lampke
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Strong Electric Field ◽  
Ceramic Coatings ◽  
Substrate Material ◽  
Oxide Ceramic ◽  
Plasma State ◽  
Electrolytic Oxidation ◽  
Oxide Ceramic Coatings ◽  
Micro Arc Oxidation ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO), also called micro-arc oxidation (MAO), is an innovative method in producing oxide-ceramic coatings on metals, such as aluminum, titanium, magnesium, zirconium, etc. The process is characterized by discharges, which develop in a strong electric field, in a system consisting of the substrate, the oxide layer, a gas envelope, and the electrolyte. The electric breakdown in this system establishes a plasma state, in which, under anodic polarization, the substrate material is locally converted to a compound consisting of the substrate material itself (including alloying elements) and oxygen in addition to the electrolyte components. The review presents the process kinetics according to the existing models of the discharge phenomena, as well as the influence of the process parameters on the process, and thus, on the resulting coating properties, e.g., morphology and composition.

Simultaneous Reduction of Wear and Corrosion of Titanium, Magnesium and Zirconium Alloys by Surface Plasma Electrolytic Oxidation Treatment

2008 ◽  
Vol 38 ◽  
pp. 27-35 ◽  
Author(s):  
H.M. Nykyforchyn ◽  
V.S. Agarwala ◽  
M.D. Klapkiv ◽  
V.M. Posuvailo
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Synthesis Method ◽  
Zirconium Alloys ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Wear And Corrosion ◽  
Electrolytic Oxidation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic

Titanium, magnesium and zirconium alloys are widely used in industrial applications, which require high wear and corrosion resistance. However current methods of improving these properties often do not satisfy the requirements of service and functional properties. An alternative approach is the application of oxide-ceramic coatings using high temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This method has shown good results for aluminium alloys and with good prospects to be used for titanium, magnesium and zirconium alloys. Development of PEO technology to improve the wear and corrosion resistance of titanium, magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic currents into account, and establishing the electrolyte content of different dopants.

scholarly journals Hybrid, oxide-ceramic coatings formed on titanium alloys by PEO-EPD processes

2016 ◽  
Vol 4 ◽  
Author(s):  
Kazek-Kesik Alicja ◽  
Krok-Borkowicz Malgorzata ◽  
Dercz Grzegorz ◽  
Pamula Elzbieta ◽  
Simka Wojciech
Keyword(s):  
Titanium Alloys ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Oxide Ceramic Coatings
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