Fe-based amorphous coating with high corrosion and wear resistance

Abstract

The amorphous coating with a new developed composition of Fe63Cr8Mo3.5Ni5P10B4C4Si2.5 has been successfully prepared by high velocity oxygen fuel technique. The amorphous coating shows good corrosion and wear resistance, which compare favourably with those of the well-known SAM1651 (Fe48Mo14Cr15Y2C15B6) and SAM2X5 (Fe49.7Cr18Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) amorphous coatings despite the absence of W, and very low Cr and Mo content. The electrochemical impedance spectroscopy (EIS) and Mott–Schottky analysis reveal that under high passive potentials the passive film on the coating reflects bi-layer structure and transpassive dissolution occurs, but the film can still remain passive due to slow ionic transport under these conditions. Donor densities of the passive films on the coatings are in the order of magnitude of 1021 cm−3 which is comparable to the reported values for passive films of SAM series amorphous coatings indicating the approximate stability of the passive film. In addition, the dominating wear mechanism of Fe-based amorphous coatings is oxidation wear.