Tribocorrosion Properties of PEO Coatings Produced on AZ91 Magnesium Alloy with Silicate- or Phosphate-Based Electrolytes

Abstract

In this work, the tribocorrosion behavior of plasma electrolytic oxidation (PEO)-coated AZ91 samples was studied. In particular, two different coatings were produced and compared. One was obtained with an alkaline electrolyte containing sodium phosphate, whereas the other one was produced with an alkaline electrolyte containing sodium silicate. The coatings were characterized with SEM-EDS and XRD techniques, and after the tribocorrosion tests, the wear scars were analyzed with SEM-EDS. The tribocorrosion behavior was evaluated measuring the OCP during a pin on disk test performed in an aggressive environment. Moreover, potentiodynamic polarization and electrochemical impedance spectroscopy tests were performed, to evaluate the corrosion resistance of the different samples in the absence of wear phenomena. The behavior of all the PEO-treated specimens was compared with the one of the untreated sample. A remarkable increase in the tribocorrosion performances after the PEO treatments was observed. Moreover, the samples obtained with the electrolyte containing silicates showed higher tribocorrosion performances.

Influences of electrolytes on tribocorrosion performance of MAO coating on AZ31B magnesium alloy in simulated body fluid

“…In this case, larger wear is always observed by the interaction between a mechanical and an electrochemical degradation process. However, there are a few works available to investigate the tribocorrosion performances of MAO coatings on magnesium alloys 21,22 . The aim of this work is to investigate the effects of electrolytes on the corrosion and tribocorrosion properties of MAO coated AZ31B Mg alloys in SBF.…”

Corrosion and Wear Behavior of WC–10Co4Cr Coating under Saturated Salt Drilling Fluid

“…Hence, a hard coating could be applied to the surface of the drill pipe or joint to improve its anti-corrosion and anti-wear [ 8 , 13 , 14 , 15 , 16 ]. There are several major coating methods to prepare hard coatings, such as high-velocity oxygen–fuel spraying [ 1 , 17 ], cold spraying [ 15 , 18 ], plasma spraying [ 19 ], micro-arc oxidation [ 20 , 21 ], high-speed laser cladding [ 22 ], high-power impulse magnetron sputtering [ 16 ], plasma electrolytic oxidation [ 23 ], and so on [ 13 , 24 ]. WC-based cemented carbide possesses high hardness, outstanding strength, and excellent toughness, so is widely used as anti-wear material [ 1 , 8 , 17 ].…”

Corrosion Behavior of Fe/Zr Composite Coating on ZK60 Mg Alloy by Ion Implantation and Deposition

“…Various kinds of biocompatible coatings have been prepared via proper surface modification techniques (including sol-gel, surface oxidation, ion beam modification and chemical conversion etc.) to reduce the corrosion rate of Mg-based alloys [8][9][10][11]. Metallic coatings have been proved to exhibit high corrosion resistance, excellent mechanical property, good biocompatibility and favorable electric conductivity, which can simultaneously enhance the corrosion resistance and surface strength without deteriorating the electric conductivity [12][13][14][15][16].…”