Metal Ions Supported Porous Coatings by Using AC Plasma Electrolytic Oxidation Processing

Abstract

Coatings enriched with zinc and copper as well as calcium or magnesium, fabricated on titanium substrate by Plasma Electrolytic Oxidation (PEO) under AC conditions (two cathodic voltages, i.e., −35 or −135 V, and anodic voltage of +400 V), were investigated. In all experiments, the electrolytes were based on concentrated orthophosphoric acid (85 wt%) and zinc, copper, calcium and/or magnesium nitrates. It was found that the introduced calcium and magnesium were in the ranges 5.0–5.4 at% and 5.6–6.5 at%, respectively, while the zinc and copper amounts were in the range of 0.3–0.6 at%. Additionally, it was noted that the metals of the block S (Ca and Mg) could be incorporated into the structure about 13 times more than metals of the transition group (Zn and Cu). The incorporated metals (from the electrolyte) into the top-layer of PEO phosphate coatings were on their first (Cu+) or second (Cu2+, Ca2+ and Mg2+) oxidation states. The crystalline phases (TiO and Ti3O) were detected only in coatings fabricated at cathodic voltage of −135 V. It has also been pointed that fabricated porous calcium–phosphate coatings enriched with biocompatible magnesium as well as with antibacterial zinc and copper are dedicated mainly to medical applications. However, their use for other applications (e.g., catalysis and photocatalysis) after additional functionalizations is not excluded.

Development of an Oxide Layer on Al 6061 Using Plasma Arc Electrolytic Oxidation in Silicate-Based Electrolyte

“…The efficiency of experiments conducted was evaluated with the help of various characterization tests, i.e., Scanning Electron Microscopic (SEM) Analysis and Field Emission Scanning Electron Microscopic (FE-SEM) analysis. The coating material, inclusion in the coatings, and oxidation properties were studied by Energy Dispersive Spectrometer (EDS) analysis, which gives elemental distribution on the sample surface [27,28]. The residual powder was also analyzed to identify the elements that did not adhere to the surface.…”

“…The reactions during the oxidation process play an important role in formulating the surface characteristics [27]. The Al metal ion exchange and reaction during the interaction has a significant value in terms of duration of process and composition of the material [28].…”

Biocompatibility and Antibacterial Properties of ZnO-Incorporated Anodic Oxide Coatings on TiZrNb Alloy

“…The main advantage of the PEO process is formation of good quality coatings on samples with complex shapes. The coatings are composed of substrate oxides and incorporated compounds from electrolyte [23,24]. It is possible to incorporate insoluble compounds/particles directly into the coating from electrolyte [25].…”

Trends and Prospects in Surface Engineering

“…Seven research papers have been published in the Special Issue of Trends and Prospects in Surface Engineering. All the presented subjects are multidisciplinary, and include Zr-C coatings [ 1 ], ultraviolet laser working in cold ablation conditions for cutting labels [ 2 ], corrosion of mechanical and electrochemical polishing of steels [ 3 ], plasma electrolytic oxidation (micro arc oxidation) of lights metals [ 4 , 5 , 6 , 7 ].…”

“…The next four papers [ 4 , 5 , 6 , 7 ] present the porous coatings fabrication by Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO). That method is used to treat metals and alloys such as: titanium, niobium, tantalum, and their alloys.…”