Abstract
In the present work Cr3C2-NiCr powder containing Al particles was deposited on ductile cast iron with high-velocity oxy-fuel (HVOF) thermal spray coating technique. An investigation was conducted to determine the role of Al particles in the Cr3C2-NiCr coating produced with HVOF technique on microstructure, mechanical and wear properties in a system Cr2C3-NiCr coating/ductile cast iron. The microstructure of the HVOF-sprayed Cr3C2-NiCr+Al coating was characterized by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). Microstructure analysis reveals the formation of coating with low porosity, good adhesion to the substrate and dense structure with irregularly shaped particles of Al arranged in strips and finely fragmented Cr3C2 particles embedded in a nanocrystalline Ni-Cr alloy matrix. In addition, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (Cr3C2-NiCr+Al)/ductile cast iron as well as microhardness and wear resistance of the coating. It was found that the addition of Al particles significantly increased resistance to cracking and wear behaviour in the studied system.
Highlights
Supersonic coatings are widely used in various industries to increase the resistance of machine parts to abrasive wear, erosion, corrosion, etc., which results in a significant increase in durability and reliability of machine parts, reduction of production costs and saving energy and materials [1,2]
The coating has a typical lamellar structure, i.e., arranged in layers flattened grains formed with powder particles that undergo sever deformation and geometric changes in the high-velocity oxy-fuel (HVOF) process
light microscope (LM) image; (b) magnified area selected in Figure 1; (c) details of the coating structure in differential interference contrast (DIC); and (d) cast iron structure composed of ferrite and perlite
Summary
Supersonic coatings are widely used in various industries to increase the resistance of machine parts to abrasive wear, erosion, corrosion, etc., which results in a significant increase in durability and reliability of machine parts, reduction of production costs and saving energy and materials [1,2]. The HVOF spray method allows the execution of coatings with special properties such as very low porosity, high adhesion, low oxygen content and with a limitation of the carbide decay process, decarburization and carbide oxidation. The coating in this process is formed primarily of particles in high-plastic state The high kinetic energy of the particles, even though they are not in a liquid state, allows them to be deformed Coatings 2019, 9, 840; doi:10.3390/coatings9120840 www.mdpi.com/journal/coatings
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
