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Electrochemical behaviour of MA8 magnesium alloy in minimum essential medium (MEM) and 0.83 wt. % NaCl solution is compared using SVET, local pH measurements and hydrogen evolution tests. Corrosion products formed on the alloy surfaces are characterized using XRD and SEM-EDX analysis. Potential by-products of cells and bacteria activities increase the sample activity in MEM at the initial stage of material immersion. Hydrogen evolution rate is higher for samples in NaCl solution in comparison with MEM. Formation of partially protective magnesium-substituted hydroxyapatite stabilizes the local pH of MEM below 9.0 and does not allow to increase the pH during corrosion.

The difference of the protective properties of the corrosion film formed on the MA8 Mg alloy in the mammalian cell culture medium (MEM) and 0.83 wt. % NaCl solution is established using OCP, PDP and EIS tests. The impedance modulus in the frequency range from 105 Hz down to 10−1 Hz for the sample immersed in MEM is higher than that for the sample immersed in NaCl solution. Ca and P rich deposits are formed in the corrosion layer on the Mg alloy in MEM. The model of the corrosion mechanism for MA8 Mg alloy in the MEM is proposed.

The morphology, electrochemical and mechanical properties of the protective composite coatings, formed on the magnesium alloy surface by means of plasma electrolytic oxidation (PEO) and fluorocarbon materials have been established. After the treatment of the PEO-coating by fluoroparaffins the impedance modulus and polarization resistance have increased by two orders of magnitude and wear resistance in more than 10 times as compared to the base PEO-layer. Hydrophobic properties of the composite coatings have been established: values of the contact angle changed in the range from 122° up to 137°, depending on the flouroparaffin type.

The paper presents results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on morphology, composition, and protective properties of the coatings produced on 5754 aluminum alloy in a mixed electrolyte. It is shown that increasing the duty cycle of a microsecond current pulses leads to a decrease of porosity and an increase of thickness of the PEO-layers, which are composed of γ-Al2O3, β-Al2O3, AlPO4, and Al2Mo3C. This improved the barrier properties and microhardness of the coating. The Young's modulus increased with an increase of the quantity of electricity due to the changes of morphological and chemical structure of the coatings. The PEO-coatings produced at a higher duty cycle and longer oxidation time are more wearproof as compared to ones formed at a shorter oxidation time and lower D values. The obtained data allowed confirming the hypothesis on phase formation mechanism.

TiO2-B nanobelts have been synthesized by hydrothermal route using TiO2-anatase precursors with different microstructure. The decrease in average size of starting product improves the degree of TiO2-B crystallinity and increases the surface area. Both of them strongly influence on the electrochemical performance of as-prepared TiO2-B: the capacity of 203 mAh g−1 is still maintained after 35 cycles, with a degradation of 0.25% per cycle for material synthesized using TiO2-anatase phase with a particle size of 25 nm. Oppositely, the samples obtained from larger particles show poorer lithium storage with a worse capacity retention.

In this study, TiO2(B) metastable β-TiO2 or bronze TiO2 was doped with Zr4+ (Zr/Ti = 0.03; 0.06) through hydrothermal approach. The materials were shown to be nanobelts (thickness: 10–l5 nm, width: 50–100 nm, length: several micrometers, and specific surface area: 72–76 m2/g). Doping the TiO2(B) structure with Zr4+ was found to be accompanied by the formation of Ti1−xZrxO2(B) (x = 0.03; 0.06) solid solutions, where the unit cell volume increases as the zirconium content rises. For doped TiO2(B), electrical conductivity increased by two order of magnitude, from 1.6 × 10−11 in an undoped sample to 8.2 × 10−10 S/cm for Zr/Ti = 0.06. After 90 charge/discharge cycles at the C/10-rate, Ti0.94Zr0.06O2(B) electrode had a capacity of 165 (mA h)/g. For undoped TiO2(B), this parameter was only 135 (mA h)/g. Moreover, Ti0.94Zr0.06O2(B) retained a reversible capacity of about 107 (mA h)/g even under an increased current load (5C). The major factors influencing the electrochemical behavior of Ti0.94Zr0.06O2(B) are the enhanced stability of the structure to lithiation/delithiation and an improved electrical conductivity.

A method of the formation of protective coatings on the MA8 magnesium alloy by plasma electrolytic oxidation (PEO) followed by treatment in an aqueous suspension of superdispersed polytetrafluoroethylene (SPTFE) has been developed. Morphological and electrochemical performances of composite polymer-containing coatings have been studied in order to qualitative and quantitative evaluation of the protective characteristics. The results indicate an increase in the corrosion resistance of the composite coating in comparison with the base PEO-coating. It has been established that the highest value of the contact angle (CA) was obtained for coatings treated in a water suspension of SPTFE.

The properties of coatings obtained by plasma electrolytic oxidation on the MA8 magnesium alloy in electrolytes containing zirconia-silica nanoparticles at a concentration of 2, 4 and 6 g/l are studied. Coating formed in electrolyte containing particles in concentration 4 g/l possesses the impedance modulus by an one order of magnitude higher compared to the base PEO-coating. The protective properties are retained after a 24-h exposure to a corrosive environment.

The paper presents a method of the formation of the composite polymer-containing coatings on a MA8 magnesium alloy by plasma electrolytic oxidation (PEO) with the subsequent application of a polymer component by spray-coating with suspension of superdispersed polytetrafluoroethylene. Composite layers significantly increase the corrosive properties of magnesium alloy. A decrease of the corrosion current density more than 3 orders of magnitude in comparison with the base PEO-coating is observed. Formed polymer-containing layers have hydrophobic properties: the values of the contact angle attain to 152°. These coatings significantly expand the field of application of magnesium alloys in such industries as automotive, aviation, instrument engineering and implantation surgery.

The plasma electrolytic oxidation is an innovative method for the surface treatment of titanium and its alloys. This review provides an overview of the historical development of the process and summarizes the current state of the art. The chemical as well as the electro- and plasma-chemical basics of the layer forming mechanisms, which comprises the substrate/electrolyte interface before discharge initiation and the different types and stages of plasma electrolytic discharge phenomena are explained within the context of titanium-based materials. How these phenomena can be influenced by the use of suitable electrolytes and controlled by the electrical regime is described. Subsequently, the microstructures and composition of the layers are described in detail, and the properties for specific applications are then discussed. The resistance of a PEO coating to corrosive environments, tribological factors, and alternating mechanical stress is viewed critically, and the extensive functional properties such as physiological compatibility, photocatalytic activity, and decorative properties are revealed. Finally, examples of various practical applications in the medical engineering, aviation, automotive, and environmental technology fields, as well as other branches of industry, are presented., M. Aliofkhazraei acknowledges comments received from Prof. A. Yerokhin during intial steps of preparation of this review paper. D.D. Macdonald gratefully acknowledges the support of the FUTURE (Fundamental Understanding of Transport Under Reactor Extremes), an Energy Frontier Research Center funded by the U.S. Department of En- ergy (DOE), Office of Science, Basic Energy Sciences (BES). E. Matykina would like to thank the support of the RTI2018-096391-B-C33 (MCIU/ AEI/FEDER, UE) and S2018/NMT-4411 (Regional Government of Madrid and EU Structural and Social Funds). S.V. Gnedenkov ac- knowledges the support of the Russian Science Foundation (No. 20-13- 00130).

The creation of substances and compositions capable of changing their properties depending on environmental conditions is an urgent and promising area of research. This work presents a method for obtaining a polymeric system consisting of polyethylene oxide and tetrafluoroethylene telomers, which film is capable of transition from hydrophilic to hydrophobic properties under the heating (from 60 °C), as well as returning to its original properties under ambient conditions. The mechanism of transition of substance’s properties from hydrophilic to hydrophobic is proposed.