Plasma Electrolytic Oxidation (PEO) Layers from Silicate/Phosphate Baths on Ti-6Al-4V for Biomedical Components: Influence of Deposition Conditions and Surface Finishing on Dry Sliding Behaviour

Abstract

Plasma Electrolytic Oxidation (PEO) layers were produced on Ti-6Al-4V in different conditions, so as to assess the influence of layer structure, current mode, duty cycle and surface finishing on microstructural features and tribological behaviour. In DC regime, the double-layer structure (silicate bath followed by phosphate bath) beneficially affected wear resistance. In unipolar pulsed DC (phosphate bath), the wear resistance of single layers improved with increasing duty cycle, due to improved microstructure and adhesion: high duty cycle single layers can be considered an alternative to double-layer deposition. Surface finishing by abrasive blasting with spheroidal glass beads leads to surface roughness decrease and hence to decreased friction and improved wear resistance. The best-performing PEO layers showed promising results in the comparison with reference materials such as CoCrMo (both uncoated and (Ti,Nb)N PVD-coated) and PVD-coated Ti-6Al-4V up to 30 N normal load.

Formation and Properties of Oxide Coatings with Immobilized Zeolites Obtained by Plasma Electrolytic Oxidation of Aluminum

“…The respectable levels of photocatalytic activity observed for all prepared coatings were most likely the result of the applied continuous DC electrical regime and the surface morphology, which entails a lower level of homogeneity, higher thickness of the porous layers, and higher porosity and roughness [33,34]. It is apparent that the highest efficiency of the MO degradation for oxide coatings formed on Al was obtained by adding Ce-loaded 13X zeolite to the supporting electrolyte.…”

Influence of Complex SiF62− Ions on the PEO Coatings Formed on Mg–Al6–Zn1 Alloy for Enhanced Wear and Corrosion Protection

“…Using PEO process, hard ceramic coatings can be formed on various kinds of light metal alloys using appropriate solutions and additives such as alkaline silicates, phosphates, etc. Though the PEO coatings have comparable mechanical properties, due to porosity and defect issues, however, the coatings need further improvement in regards to corrosion protection, for long-term applications [1][2][3][4][5][6][7].…”

Tribological Behavior of Functional Surface: Models and Methods

“…They can be reduced by surface engineering. The proper creation of surface topography may cause a decrease in friction and wear [2,3]. The frictional properties of machined elements can be improved by surface texturing [4][5][6].…”

“…The frictional properties of machined elements can be improved by surface texturing [4][5][6]. Coatings make the surface life robust from wear [3,[5][6][7][8][9][10][11] and corrosion [7][8][9]. The resistance to motion can be improved by change of the oil [12].…”

“…Its tribological properties can be improved by various engineering techniques, with PEO (plasma electrolytic oxidation) being one of them. The authors of [3] studied the effect of process parameters and surface finishing of the PEO-treated Ti-6Al-4V alloy using different process parameters on dry sliding behavior. Surface finishing by abrasive blasting with spheroidal glass beads led to a reduction in surface roughness height and to higher wear resistance and less friction.…”