Evaluation of metallic structures and material properties of thermal sprayed coatings using stainless-steel wires

Abstract

ABSTRACT To evaluate the fundamental differences between the standard wire flame-sprayed coatings of stainless-steel wires, the differences in their characteristics are discussed from a metallurgical point of view. Austenitic (SUS304 and SUS316) and martensitic (SUS420J2) stainless steels were used in this study. The SUS420J2 and SUS304 sprayed coatings were composed of austenite and martensite, whereas the SUS316 sprayed coating was composed of only austenite. The dense thermally sprayed coating of SUS316 was due to oxygen distribution, which corresponds to marble-pattern oxidised structures. Additionally, an increase in the carbon content was observed after thermal spraying. However it is difficult to determine the distribution of carbon; therefore, it is considered that carbon distribution is supersaturated at a certain amount and carbon exists as a solid solute in the austenite phase. Finally, the increase in the carbon content is related to the progress of corrosion.