Influence of the electrical parameters of the anodizing PEO process on wear and corrosion resistance of niobium

In this work, anodic coatings were obtained on niobium by plasma electrolytic oxidation (PEO). Surface topography variation depending on the electrical perturbation mode of the PEO process was evidenced. Coatings obtained at galvanostatic mode exhibited the formation of circular pores with no variation in morphology distribution with current density. Meanwhile, the coatings obtained under a galvanostatic - potentiostatic condition exhibited different topographies according to the potential applied and better corrosion and wear resistance. Most of the coatings showed breakdown potential and formation of sparks at approx. 260 V. However, coating obtained at 300 V exhibited the formation of a compact structure with good tribological performance (30 times better than that of the substrate (Wear rate 0.9 × 10−9 kg/N.m) and high corrosion resistance due to low porosity (Rp = 10.52 Mohm cm2). •Surface topography variation is related to coating growing rate.•Potentiostatic mode allows controlling the coating porosity.•Dense coatings exhibit superior tribological and corrosion properties.•Developed coatings by PEO on Nb augur good biomechanical behavior of the material.•Electrical parameters of coatings indicate internal changes in coating structure.