The Influence of PSA Pre-Anodization of AA2024 on PEO Coating Formation: Composition, Microstructure, Corrosion, and Wear Behaviors

Abstract

In the frame of the current work, it was shown that plasma electrolytic oxidation (PEO) treatment can be applied on top of phosphoric sulfuric acid (PSA) anodized aluminum alloy AA2024. Being hard and well-adherent to the substrate, PEO layers improve both corrosion and wear resistance of the material. To facilitate PEO formation and achieve a dense layer, the systematic analysis of PEO layer formation on the preliminary PSA anodized layer was performed in this work. The microstructure, morphology, and composition of formed PEO coatings were investigated using scanning electron microscopy (SEM), x-ray diffraction (XRD), and glow-discharge optical emission spectroscopy (GDOES). It was shown that under constant current treatment conditions, the PSA layer survived under the applied voltage of 350 V, whilst 400 V was an intermediate stage; and under 450 V, the PSA layer was fully converted after 5 min of the treatment. The comparison test with PEO formation on the bare material was performed. It was confirmed that during the “sparking” mode (400 V) of PEO formation, the PEO coatings, formed on PSA treated AA2024, were more wear resistant than the same PEO coatings on bare AA2024.

Chromium Luminescence in Plasma Electrolytic Oxidation Coatings on Aluminum Surface

“…Due to its crystalline structure and chemical composition, this material is chemically inert with outstanding thermal stability and hardness. It is mainly exploited as a ceramic and is widely used for industrial purposes where a hard, mechanical shock-resistant, chemically inert, or biocompatible material is required [9][10][11].…”

Properties of ZnO/ZnAl2O4 composite PEO coatings on zinc alloy Z1

“…The oxide layers developed by PEO method are usually hard and well adherent to the substrates and can provide effective corrosion and wear resistance [ [8][9][10][11][12] ]. Thus, PEO treatments are well known for corrosion and wear protection of magnesium [ 5 , 7 , [15][16][17], aluminium [ [18][19][20][21][22][23] and titanium [ [24][25][26][27][28][29] ] based alloys.…”

Investigation of Growth Mechanism of Plasma Electrolytic Oxidation Coating on Al-Ti Double-Layer Composite Plate

“…Therefore, surface protection treatment is required before its application. There are many surface protection techniques, including anodic oxidation [3], plasma electrolytic oxidation (PEO) [4], and plasma spraying [5]. Among these techniques, PEO is an effective surface modification technique for fabricating ceramic oxide coatings on light metals, which has been widely applied to Al, Ti, and other valve alloys [6,7].…”