Kinetics and mechanism of electrolytic corrosion of titanium-based ceramics in 3% NaCl solution

The kinetics of electrolytic oxidation (in 3% NaCl solution at 20 °C) of TiN–AlN, TiB2–AlN, TiB2–TiN and TiC0.5N0.5 binary ceramics, manufactured by HIP method, were studied using a potential-dynamic method of polarization curves. For determination of oxidation mechanism, the chemical analysis concerning titanium ions state in the solution as well as an XRD, SEM and AES analyses of oxidized surface layers were used. In all the cases the oxidation of ceramics above proved to be the multistage process, the peculiarities of different stages were discussed on the base of experimental data obtained by the methods pointed out. It was shown that these ceramics are exceptionally corrosion-resistant. The rate of oxidation only slightly increases in the row: TiN–AlN → TiB2–AlN → TiB2–TiN → TiC0.5N0.5.