Heat Resistance and Corrosion Resistance of Complex Chromium+Aluminum Diffusion Coatings on Titanium Alloy VT6
DOI:
https://doi.org/10.20535/1810-0546.2013.1.90703Abstract
In this paper we study the microstructure, phase and chemical composition of complex chromium+aluminum diffusion coatings obtained by simultaneous saturation of titanium alloy VT6 with chromium and aluminum from powder mixtures. We discover that coatings consist of three separate layers of Al3Ti, AlTi, AlTi3 phases. The microhardness of diffusion multilayers in the area of Al3Ti phase is 7,1–9,0 GPa, of the main diffusion layer AlTi – 5,2–8,2 GPa and 11,0 GPa for the AlTi3 phase, that is by 2-4 times higher the microhardness of initial VT6 (3,63 GPa). The heat resistance of the titanium alloy VT6 increases from 450 to 700 °C due to formation of protective oxides films of aluminum and chromium on the surface. Corrosion resistance of VT6 increases by 2,52 times in an aqueous solution of 5 % HOO (CH2)4COOH acid and by 9,53 times in an aqueous solution of 3 % H2O2. Furthermore, diffusion chromium+aluminum coatings obtained using the proposed method may be suitable for practical use on parts and constructions made of titanium alloy VT6 to improve their performance properties and to extend the operation life under conditions of high temperatures, abrasion and relevant aggressive environments.References
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