Investigation of the Mechanical Properties and Wear Resistance of Intermetallic FeAl-Based Plasma Sprayed Coatings

Abstract

Studies of the mechanical characteristics and abrasive resistance of FeAl-based plasma sprayed coatings are presented. Coatings were obtained by plasma spraying method using iron aluminide powders of Fe3Al, Fe-AlMg and Fe-TiAl systems. The powders were prepared by mechanochemical synthesis. The mechanical characteristics (hardness and elastic modulus) of the coatings were determined by microindentation method. It has been found that the hardness of the coatings is in the range of 2.9…5.4 GPa, the elastic modulus is in the range of 80…100 GPa. It is shown that the gas-abrasive resistance of all tested coatings at room temperature exceeds the wear resistance of St3 steel 1.4…4.3 times; when dry abrasive/rubber wheel testing the resistance of the coatings exceeds the resistance of St3 2.1…3.8 times. The resistance of Fe3Al, Fe-AlMg and Fe-TiAl coatings is higher 2.2…3.1 times than resistance of St3 steel under conditions of gas-abrasive wear at a temperature of 550 °C; the resistance of Fe3Al and Fe-TiAl coatings under the same conditions exceeds the resistance of heat-resistant steels 1.2…1.5 times. In all cases Fe3Al coating has the highest wear resistance because of low porosity and low content of brittle phases in the coating. An assessment of the relationship between the mechanical properties of coatings and wear resistance showed that the wear resistance of coatings increases with an increasing of their elastic modulus. Based on the results of studies the possibility of using FeAl-based coatings for the protection and hardening of parts and constructions operating under conditions of abrasive wear at temperatures range from 20 to 550 °C is shown.