In Situ Synthesis of FeAl Intermetallic Coatings by Wire Electrical Explosion-Spraying

Abstract

FeAl intermetallic compounds have several advantages over other Fe-based alloys. Surface engineering was used to prepare intermetallic FeAl coatings to exploit the properties of these components. However, this method requires complex processing, and controlling the phase composition of the coating makes it difficult to prepare Fe-Al coatings using conventional surface engineering. In this study, a novel constrained wire electrical explosion spraying device was used to prepare FeAl coatings. A FeAl intermetallic coating was successfully synthesized by electrical explosion spraying of twisted 316L/Al wires. The charging voltage affected the phase compositions, microstructures, and deposition efficiencies of the coatings. Considering the phase composition, deposition efficiency, and microstructure of the coating, a charging voltage of 8.8 kV was determined to be suitable based on the overheating factor of the twisted wires, which influenced the amount of liquefied and gasified metal. Intermetallic FeAl compounds were formed as the clusters of liquefied and gasified 316L and Al were cooled. In addition to the overheating factor, the wire expansion velocity was influenced by the charging voltage. The combined effects of the overheating factor and expansion velocity determine the temperature and velocity of the explosive products, ultimately affecting the degree of product flattening and coating microstructure.