Electrochemical study of Zr-1Nb alloy with oxide coatings formed by plasma electrolytic oxidation

Abstract

Plasma electrolytic oxidation (PEO) coatings were formed on Zr-1Nb alloy in electrolyte containing 9 g/L sodium silicate, 5 g/L sodium hypophosphite, and 6 g/L submicron yttrium oxide powder at current densities 20, 30, and 40 A/dm2. The coatings surface morphology was studied by scanning electron microscope. The electrochemical behavior of coated and uncoated samples was investigated after 1-and 7-days exposure in 10 % HCl. The samples with PEO coatings formed at 30 A/dm2 current density had the best corrosion protective properties after 1-day exposure in 10 % HCl. After 7-days exposure in 10 % HCl the samples with PEO coatings formed at 30 and 40 A/dm2 current densities showed greater corrosion resistance then samples with PEO coatings formed at 20 A/dm2 current density and uncoated samples.

Influence of PEO Electrolyzer Geometry on Current Density Distribution and Resultant Coating Properties on Zr-1Nb Alloy

“…Plasma electrolytic oxidation (PEO) is an environmentally friendly surface treatment method that is successfully used to create wear-resistant, corrosion-resistant, heat-resistant, biocompatible and decorative coatings on aluminum, titanium, zirconium and other light alloys [1][2][3][4]. Unlike aluminum and titanium, zirconium alloys are less investigated in terms of the specific features of the PEO process mechanism; however, recent studies appear to be focused on Zr and its alloys [5][6][7]. One important Zr alloy application is nuclear fuel cladding which suffers from hydrogen embrittlement in the boiling water environment of a power plant [8,9]; the PEO coatings show a good promise for fuel cladding corrosion protection [10,11].…”