Xiuyong Chen

Fe-based amorphous coating with high corrosion and wear resistance

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 1021u2005cm−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. GRAPHICAL ABSTRACT

Tribocorrosion behaviours of cold-sprayed diamond–Cu composite coatings in artificial sea water

ABSTRACT Frictional components in the marine environment always face a synergistic effect of wear and corrosion. Diamond-based composite coatings are known for their excellent wear performances, but few studies were conducted relating to their marine applications. Herein, diamond–copper composite coatings were successfully deposited on stainless steel 316L plates by the cold spraying, employing diamond powder coated with thin copper (Cu) layer. The diamond–Cu composite coatings with a diamond content of 31.79% were successfully fabricated. The coatings showed significantly enhanced wear resistance tested in artificial sea water with the reduced friction coefficient from 0.32 for the Cu coating to 0.10 for the diamond–Cu coating. Further electrochemical testing showed promoted anti-corrosion performances of the diamond-containing coatings. The newly constructed diamond–Cu coatings show encouraging promises as anti-tribocorrosion layers for marine structures.

Corrosion and Algal Adhesion Behaviors of HVOF-Sprayed Fe-Based Amorphous Coatings for Marine Applications

In this study, Fe-based amorphous/nanocrystalline coatings consisting of Fe53Cr19Zr7Mo2C18Si were fabricated by high-velocity oxy-fuel spray. For comparative study, further crystallization annealing treatment at 750xa0°C was carried out for the coatings. The microstructure, corrosion resistance and algal adhesion behaviors of the as-sprayed and annealed coatings were systematically investigated by scanning electron microscopy, x-ray diffraction, transmission electron microscopy, electrochemical testing and laser confocal scanning microscopy, respectively. Results show that the as-sprayed coatings exhibited excellent corrosion resistance and decreased algal adhesion, while the annealed coatings displayed compromised anti-corrosion performances, but significantly inhibited the adhesion of typical algae Phaeodactylum tricornutum.