Influence of the thermal-spray procedure on the properties of a nickel-chromium coating
V. HIGUERA, F. J. BELZUNCE, A. CARRILES
JOURNAL OF MATERIALS SCIENCE
Abstract
A modied NiCr coating was thermal-spray projected using different procedures (ame, plasma, HVOF and HFPD) onto stainless steel specimens. This type of coating is normally used as protection against heat, corrosion and erosion actions encountered in superheater and reheater tubes in power plant boilers. The microstructures, porosities, oxide contents and microhardnesses of the coatings were determined. Thermal fatigue tests under an atmosphere similar to power plant service conditions were conducted in an experimental combustion chamber and, nally, the adhesion between the substrate and the coating layer was evaluated by means of tensile tests. The results obtained are discussed, with special attention being paid to the specic characteristics of the different spraying procedures.
Key words:Thermal fatigue
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