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Corrosion inhibition of Ti6Al4V alloy by a protective plasma electrolytic oxidation coating modified with boron carbide nanoparticles

2021; Elsevier BV; Volume: 430; Linguagem: Inglês

10.1016/j.surfcoat.2021.127987

1879-3347

Parisa Molaeipour, Saeed Reza Allahkaram, Sajjad Akbarzadeh,

Titanium Alloys Microstructure and Properties

Plasma electrolytic oxidation (PEO) is a cost-effective and versatile technique to achieve protective oxide coatings in light metals. Composite coatings containing B4C nanoparticles were produced by the PEO technique on a Ti6Al4V alloy. The influence of nanoparticles on the microstructure and corrosion resistance of the prepared ceramic composite coatings, as well as its incorporation mechanism into the PEO layer, were investigated. B4C nanoparticles were added to aluminate-based electrolytes and a pulse power supply was used as a constant voltage regime to obtain PEO composite coatings. Improvement in corrosion protection was also assessed by electrochemical impedance spectroscopy (EIS) and polarization tests, illustrating that a reduction in the corrosion resistance ratio was 8 for the composite coating compared to 16 for the sample without nanoparticles, after three weeks of immersion. The effect of nanoparticles on the phase composition was examined by X-ray diffraction (XRD) tests. Moreover, scanning electron microscopy (SEM) images illustrated the capability of B4C nanoparticles in filling the inherent pores of PEO coatings.