Analysis of Crystal Structure of Oxide Ceramic Coatings Formed on VT5 and VT14 Titanium Alloys

X-ray phase analysis of oxide ceramic coatings formed on the alloys VT5 (94 Ti–5Al–1V), VT14 (89Ti–6Al–2V–Mo–3) in the process of plasma electrolyte oxidation in the electrolyte KOH (3 g/l), Na2SiO3 (2 g/l) and KOH (5 g/l), Na2SiO3 (5 g/l) was fulfilled. It was established that within 5 min of the synthesis of an oxide ceramic coating in an electrolyte with a composition of KOH (5 g/l) and Na2SiO3 (5 g/l), an oxide ceramic coating with a thickness of 7–9 μm is formed on the VT5 titanium alloy, and with a thickness of 9–14 μm on the VT14 alloy. From the analysis of cross sections, it was established that after 60 min synthesis the thickness of the oxide ceramic coating on the VT5 alloy is 80–100 μm, and on VT14 it is 90–150 μm. This is enough to form a protective surface. An increase in the synthesis time leads to a significant increase of the thickness of oxide ceramic coatings over 100 μm and an increase in the rutile content. This leads to an increase in the microhardness of the coatings. The image segmentation method was used to analyze the porosity. It is established that the minimum pore sizes for VT5 is 6.93 × 10–14 m2 and for VT14—is 2.77 × 10–13 m2.