In this study, wear and electrochemical corrosion behaviour of as-cast magnesium (Mg)/ multiwall carbon nanotube (MWCNT) and plasma electrolytic oxidation (PEO) coated Mg/ MWCNT samples were evaluated by dry sliding wear tests and potentiodynamic corrosion tests, respectively. In this respect, Mg/MWCNT composite was manufactured by stir casting route. X-ray diffraction (XRD) analysis shows that the presence of Mg, MgO and Mg 2 SiO 4 phases for coated samples. The corrosion rate of the coated samples is about 1.6 times lower than that of un-coated Mg-MWCNT composite. From the wear tests, it is concluded that PEO coating leads to significant improvement in wear resistance in comparison with un-coated Mg/MWCNT composite. It is observed that wear mechanisms are abrasion and oxidation.

Micro-arc oxidation (MAO) coating was prepared on Ti6Al4 V alloy in the electrolyte based on different ratios of calcium acetate and a fixed ratio of sodium phosphate with/without Ag additive. The surface, elemental and phase compositions, and dry wear tests of the MAO coating were analysed. The X-ray diffraction results presented that the MAO coating formed rutile, anatase and hydroxyapatite. The results show that the coating performance was improved when Ag additives were included. The wear resistance of the MAO coatings was increased by the addition of Ag.

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Micro arc oxidized TiO2 coatings were prepared in different concentrations of (CH3COO)2Ca•H2O and different coating times on biomedical Ti6Al4V alloy. The surface topography, phase, and element composition of the coatings were characterized by scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectrometry, respectively. The micro arc oxidation treated Ti6Al4V alloy was immersed in a simulated body fluid to study the bioactive deposition properties on the surface of TiO2 coating. Immersion tests indicate that the specimens coated in the high rate Ca-containing electrolyte are most effective when compared with the specimen containing less Ca-content.

This study aimed to improve the tribological behavior of electrolytic plasma treated (EPT) ductile iron (DI). For this purpose, ductile iron was electrolytic plasma hardened under different processing parameters (treatment time and thermal cycle). Three different types of specimens were tested: untreated DI, electrolytic plasma hardened DI and remelted DI by two type wear test. It was found that remelted DI performed much better concerning wear resistance than the other samples. The microstructure of the hardened specimens was investigated using optical microscopy. Microhardness profiles and surface hardness were investigated via the Rockwell test. The microstructure and hardness of the EPT hardened layer were dependent on the processing parameters, with the hardness values reaching the range 880-1080 ± 10 HV0.2. K e y w o r d s : electrolytic plasma hardening, ductile iron, hardness, remelting, wear