The Energy Efficiency of the Plasma Electrolytic Oxidation (PEO) Coating Process

Lead Research Organisation: University of Cambridge
Department Name: Materials Science & Metallurgy

Abstract

The project will involve high speed synchronised electrical and optical monitoring of individual discharges, in combination with gas composition measurement, during PEO of several metals. This will be done using a range of waveforms and supply frequencies. The focus will be on mechanisms of energy consumption, with growth of water vapour bubbles at the top of plasma channels known to be a prime source of energy absorption. It's also known that high frequencies, in the kHz range (such that the half-cycle time starts to approach the period between discharges), can promote formation of discharges during the cathodic part of the cycle. PEO is not a conventional electrochemical process, and sparking simply exposes the metal to oxidizing agents in the plasma, so cathodic discharges could improve the energy efficiency. Correlations will be explored between PEO conditions and coating microstructure, using X-ray tomography to capture 3-D pore architectures.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509620/1 30/09/2016 29/09/2022
1796039 Studentship EP/N509620/1 30/09/2016 30/03/2020 Matthew O'Hara
 
Description A mechanism has been proposed for the incorporation of small particles into Plasma Electrolytic Oxidation (PEO) coatings. Particle incorporation into this type of coating is of interest to many industrial players, as it could lead to the improvement of certain coating properties such as wear and corrosion resistance, and biocompatibilty. It was shown that particles are incorporated predominantly via the refilling of discharge pores and not by electrophoretic attraction to the surface. It is also possible that particle incorporation decreases the energy consumption of the coating process, since coating material is essentially "pre-made" and is incorporated into the coating, rather than electrical energy being used to convert the substrate to oxide.
Exploitation Route This output was based on oxide particles, but there is no reason why other functional particles could not be incorporated in the same way, e.g. PTFE / graphite to form self-lubricating surfaces.
Sectors Aerospace, Defence and Marine,Energy,Manufacturing, including Industrial Biotechology,Transport

URL https://doi.org/10.1016/j.surfcoat.2020.125354