X-ray diffraction (XRD), scanning electron microscope (SEM), immersion, electrochemical, and tensile tests were employed to analyze the phase constitution, microstructure, corrosion behaviors, and tensile properties of a Ti-6Al-4V alloy and a newly-developed low cost titanium alloy Ti-4Al-2V-1Mo-1Fe. The results showed that both the Ti-6Al-4V and Ti-4Al-2V-1Mo-1Fe alloys were composed of α and β phases. The volume fractions of β phase for these two alloys were 7.4% and 47.3%, respectively. The mass losses after 180-day immersion tests in 3.5 wt.% NaCl solution of these alloys were negligible. The corrosion resistance of the Ti-4Al-2V-1Mo-1Fe alloy was higher than that of the Ti-6Al-4V alloy. The tensile tests showed that the Ti-4Al-2V-1Mo-1Fe alloy presented a slightly higher strength but a lower ductility compared to the Ti-6Al-4V alloy.

Micro-arc oxidation (MAO) treatment can effectively improve the wear resistance, corrosion resistance, and mechanical strength of aluminum alloy substrates. Improving the porous structure of MAO film and effectively sealing the pores is a significant research issue. In this study, the MAO treatment of 5052 aluminum alloy was carried out in silicate electrolytes. The MAO films were sealed with different concentrations of SiO₂ nanoparticles. The effects of SiO₂ nanoparticle content on the MAO films’ microstructure, mechanical properties, and corrosion performance were systematically investigated. When adding SiO₂ nanoparticles to electrolytes, the particles were deposited at the micropores of the film, which could effectively seal the porous MAO film and significantly improve its corrosion and wear resistance. The corrosion resistance and wear resistance properties were optimal with 5.0 g/L SiO₂ addition. Compared to the unsealed film, the corrosion current density and corrosion rate decreased from 1.24 × 10⁻⁹ A/cm² and 1.47 × 10⁻⁵ mm/a to 7.78 × 10⁻¹⁰ A/cm² and 9.15 × 10⁻⁶ mm/a, respectively. Moreover, the average friction coefficient of the sealed film was 0.606, which was ~19.3% lower than that of the substrate and 3.3% lower than for the unsealed film.

In this study, Ni–P, Ni–W–P and Ni–B coatings were electrolessly plated on aluminium alloy substrates. All coatings were uniform and adherent with shiny metallic appearances. A systematic study was performed to evaluate the coating mechanical properties including hardness and wear resistance. The Ni–B coating possessed a superior mechanical performance, showing the highest hardness and wear resistance among the examined coatings. Besides, a further study regarding the wear behaviour confirmed a different wear mechanism of Ni–B coating when compared to the Ni–P and Ni–W–P coatings under the wear tests, which is revealed by the 3D profile images of wear tracks.