| A Plasma Electrolytic Oxidation (PEO) process was used to produce thin oxide coatings on a Zr-2.5wt%Nb alloy. Effects of current density on surface morphologies and wear properties of PEO coatings were investigated and compared to the substrate and the black oxide coating. Corrosion properties at ambient and high temperature/pressure conditions were studied using potentiodynamic polarization tests and autoclave tests, respectively. Autoclave tests were carried out at 300°C and 10MPa in 0.05M LiOH solutions. After the autoclave tests, PEO coatings had larger weight gains in the first 10-day-exposure than the black oxide coating. However, the black oxide coating exhibited a similar weight gain to PEO coatings after the tests. PEO coatings prepared at low current densities had lower weight gains. Although the black oxide coating exhibited a good corrosion resistance, it had a much lower wear resistance than the PEO coatings. |
