Duplex surface treatment of metallic alloys combining cold-spray and plasma electrolytic oxidation technologies

Abstract

Plasma electrolytic oxidation (PEO) is widely used to improve the corrosion and wear resistance of lightweight metals such as aluminium alloys by the formation of a ceramic oxide coating. However, the PEO process remains ineffective for ferrous metals and, when applied to magnesium alloys, oxide coatings are usually thin and porous. To overcome these limitations, the feasibility of applying a duplex treatment combining cold-spray deposition (CS) and PEO is investigated. Cold-sprayed aluminium coatings are deposited on magnesium (EV31) and steel (S235) substrates prior to PEO. Investigation of this duplex process evidences the efficiency of such a two-steps process to form thick, dense and crystalline alumina coatings on both magnesium and steel substrates. The growth kinetic of the duplex CS-PEO oxide layer is enhanced by a factor of 3 compared to single-step PEO processing of bulk aluminium substrates. Results are discussed by considering the effect of the porosity through the coldsprayed aluminium coating on the mechanism of oxidation during the subsequent PEO treatment.

Plasma Electrolytic Oxidation (PEO) Process—Processing, Properties, and Applications

“…PEO process is often inefficient for ferrous materials and produces a porous, thin coating for magnesium alloys. Hence to overcome these disadvantages, Martin et al [ 222 ] investigated the duplex treatment of merging cold-spray (CS) deposition process with PEO. Initially, they performed a 1050 Al powder cold sprayed coating on an S235 steel and EV31 magnesium sample.…”

The Tribological Properties of Plasma Electrolytic Oxidation Layers Synthesized on Arc Spray Coatings on Aluminum Alloys in Contact with Various Friction Materials

“…The expansion of the functionality of thermally sprayed aluminum coatings after their modification using PEO processing has already been demonstrated previously [42][43][44][45][46][47][48]. For the same purpose, plasma or cold spray deposition of aluminum coatings is also used [49,50], and aluminum, steel and titanium are used as the substrates [51][52][53][54][55][56][57][58].…”

A new strategy to prepare alumina-zirconia composite or multilayered coatings by combining cold-spray deposition and plasma electrolytic oxidation

“…Combining cold spray deposition (CS) with plasma electrolytic oxidation can advantageously overcome these limitations, and make it possible to elaborate Al 2 O 3 / ZrO 2 composite coatings on non-valve metals, while keeping the main advantages of the PEO process. Based on recent results [79], the present study aims at exploring the feasibility of growing (Al 2 O 3 , ZrO 2 )-based composite coatings on steel by a duplex process within two different configurations of CS and PEO. A first one consisted in producing a ZrO 2 / Zr / Al multilayer composite coating with the aim of replicating the typical arrangement of thermal barrier coatings (TBCs) [30,31].…”