Modification of Microstructure and Surface Properties of Ti-6Al-4V Alloy by Molybdenum Disilicide Particles Using Micro-Arc Oxidation Process

As an effective surface modification technique, micro -arc oxidation (MAO) is now widely used to improve the hardness and wear resistance of Ti and its alloys by low-cost and thick ceramic coatings. In this study, molybdenum disilicide (MoSi2) - modified ceramic coatings were deposited on Ti-6Al-4V alloy (340 HV) by MAO using an aqueous solution of Na2SiO3, (NaPO3)6 and NaOH and MoSi2 particles. MoSi2 particles (3, 5, and 7 g/l) from wastes of furnaces electrodes were introduced into the electrolyte to improve the microstructure and surface properties of Ti-6Al-4V alloys. A scanning electron microscope (SEM), dispersive spectroscopy (EDS), X-ray diffraction (XRD), and mechanical tests (microhardness and wear) were used to identify the coating properties, morphologies, and phases. The findings showed that the addition of 5 g/l MoSi2 increased the thickness and hardness of MAO coatings from 19.08 mu m and 910 HV to 33.12 mu m and 1260 HV, respectively. Also, the wear resistance by means of weight losses of uncoated alloys enhanced by 68% and 100% after MAO and 5 g/l MoSi2 modifiedMAO coatings, respectively. Results of this work will promote future works in using of industrial wastes in surface engineering of Ti-6Al-4V alloys by MAO technique for wear resistance applications.