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The Role of Surface Engineering in Tribology
Published in Jitendra Kumar Katiyar, Alessandro Ruggiero, T.V.V.L.N. Rao, J. Paulo Davim, Industrial Tribology, 2023
P. Kumaravelu, Sudheer Reddy Beyanagari, S. Arulvel, Jayakrishna Kandasamy
Plasma electrolytic oxidation (PEO) is the technique generally used for coating metal alloys. Here, the plasma discharge is created in the metal electrolyte interface, allowing the surface to turn into a dense hard ceramic oxide layer without causing damage to the substrate surface. The Keronite PEO method uses a complex combination of oxide growth, fusing, re-crystallization of the oxide film, and partial metal dissolution at tiny levels to create an oxide layer. Extensive plasma discharges on the surface of Keronite PEO might make it an aggressive process, causing the oxide layer to explode at tiny levels at very high local pressures. The operating temperature for the PEO method is between 12 and 30 degrees Celsius. Additionally, the electrolyte’s elemental co-deposition may result in the creation of a ceramic layer on the surface, resulting in crystalline and amorphous phases in addition to oxidation. Compared to hard-anodized coating, the PEO coating was two or three times greater in elastic modulus and hardness. This eventually increased the wear resistance of PEO coating over the hard anodized coating [21].
Contemporary Machining Processes for New Materials
Published in E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan, Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan
A cost-effective electrochemical procedure for surface treatment of steels employing plasma is plasma electrolytic oxidation (PEO). It can be mainly applied to valve metals or their alloys including Ti, Al, Mg, and Zr, and recent reports also include non-valve metals like Zn, Hf, Ta, and Nb, as well as diluted alkaline and environmental-friendly solutions containing phosphate, silicate, and aluminate anions. With such wide possibilities, PEO is a promising method able to produce porous, high crystalline, and about 1–100 μm thick oxide coatings. As-obtained coatings have demonstrated good adhesion to the substrate, high surface microhardness, high-temperature shock tolerance, significant resistance to corrosion and wear, and a significant insulation resistance in working conditions (Attarzadeh et al., 2021).
Plasma Electrolytic Oxidation
Published in Hatem M.A. Amin, Ahmed Galal, Corrosion Protection of Metals and Alloys Using Graphene and Biopolymer Based Nanocomposites, 2021
Aleksandra A. Gladkova, Dmitriy G. Tagabilev, Miki Hiroyuki
The process of PEO consists of several stages (Fig. 1): Anodizing without visible plasma discharges and/or electrolysis (simultaneous flow and electrophoresis are possible when particles, such as oxides, are introduced into the electrolyte);Plasma electrolytic oxidation in the presence of spark discharges;Plasma electrolytic oxidation in the presence of plasma micro-discharges on the surface of the working electrode;Plasma electrolytic oxidation in the presence of plasma arc discharges.
EUROCORR 2020: ‘Closing the gap between industry and academia in corrosion science and prediction’: Part 3
Published in Corrosion Engineering, Science and Technology, 2021
‘Development of wear resistant coatings for titanium alloys in biomedical applications’ was described by S. Lederer (DECHEMA, Germany). Although titanium is the material of choice for biomedical applications, it has low wear properties. Plasma Electrolytic Oxidation (PEO) is one method of improving wear resistance. Using an aluminate/zirconia electrolyte, this was performed on titanium grade 5. Tribocorrosion tests were carried out using a corundum ball. Under dry conditions, it was found that wear rate increased due to the influence of third body particles. In-situ polarisation experiments in Hank’s Solution (inorganic salts, supplemented with glucose) showed a cathodic shift to the OCP; sliding velocity was more influential than load. EIS results confirmed a correlation between nanoindentation tests (relating wear rate to H/E or hardness/Young modulus) were 0.02–0.08 for PEO coating, comparing favourably with diamond 0.09) or hardened steel (0.023).
Plasma electrolytic fluorination on Mg alloys: coating growth and plasma discharge behaviour
Published in Surface Engineering, 2021
Yuming Qi, Zhenjun Peng, Jun Liang, Peng Wang
Plasma electrolytic oxidation (PEO) is acknowledged as a unique method for fabricating oxide ceramic coatings on light metals (Mg, Al and Ti) and their alloys. The resultant PEO coatings, characterised by superior mechanical properties and chemical stability of oxide composition, can successfully protect these metal products from corrosion and wear failures and thus extend their service lives [14,15]. PEO technology has practically applied in modern industries, such as military, aerospace, automotive and 3C products. In addition, it is promising for the surface modification of orthopaedics implants and medical devices because of the natural biocompatibility of Mg, Ti and their individual alloys and oxides [7,8,16,17].