Corrosion Resistance of Coatings Based on Chromium and Aluminum of Titanium Alloy Ti-6Al-4V

Abstract

Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings are widely used to solve this challenge. The article aims to obtain the corrosion-electrochemical properties and increase the microhardness of the obtained coatings compared with the initial Ti-6Al-4V alloy. For this purpose, corrosion resistance, massometric tests, and microstructural analysis were applied, considering various aggressive environments (acids, sodium carbonate, and hydrogen peroxide) at different concentrations, treatment temperatures, and saturation times. As a result, corrosion rates, polarization curves, and X-ray microstructures of the uncoated and coated Ti-6Al-4V titanium alloy samples were obtained. Histograms of corrosion inhibition ratio for the chromium–aluminum coatings in various environments were discussed. Overall, the microhardness of the obtained coatings was increased 2.3 times compared with the initial Ti-6Al-4V alloy. The corrosion-resistant chromaluminizing alloy in aqueous solutions of organic acids and hydrogen peroxide was recommended for practical application in conditions of exposure to titanium products.