Formation of Fe-Based Amorphous Coating Films by Thermal Spraying Technique

Abstract

Some amorphous Fe-Cr-P-C coating films having high hardness and high corrosion resistance have been produced by a newly developed thermal spraying technique. In order to control the temperatures of the powder particles in the flame spray and the substrate, a newly developed cylindrical nozzle, with external cooling nitrogen gas, was mounted to the front end of the thermal spraying gun. Fe 70 Cr 10 P 13 C 7 films with various external cooling gas velocities between 20 m/s and 40 m/s exhibited entire amorphous structure without oxides and/or unmelted particles. Corrosion-resistance of the films was observed in immersion tests using various corrosive liquids. An amorphous film was formed on the surface of the shaft sleeve of the slurry pump by using the cylindrical nozzle. This shaft sleeve was installed in the slurry pump of chemical fertilizer maker's production line and the life test was done under the real operation condition for two months.

Influence of Substrate Temperature on Structure and Adhesion Strength of Fe–Cr–P–C Amorphous Coating Films Produced by Thermal Spraying Technique

“…Corrosion testing has demonstrated that the Fe-10Cr-based amorphous coating film exhibited a high corrosion resistance equal to that of Hastelloy C and commercially produced pure titanium. 3) High corrosion resistance of the Fe-35Cr-based amorphous coating film was observed in immersion tests using 35% hydrochloric acid. 4) For practical applications of these Fe-based amorphous coating films, the most important point is improvement of the adhesion strength between the sprayed coating films and the substrates, which may depend on the structure of the sprayed coating films and the density of the pores in the boundary region between the sprayed coating films and the substrates.…”

The Microstructure and Wear Properties of Laser-Clad WC-Cr<SUB>3</SUB>C<SUB>2</SUB> Cermet Coating on Steel Substrate

“…Thus, these carbides are widely used for producing ceramic-metal composite coatings on the substrate by conventional hardfacing techniques, such as thermal spraying, plasma spraying, electroslag remelting and arc welding, to improve wear resistance. [1][2][3][4][5] However, the surface coating produced by these technique had some disadvantages, such as the composite coatings with porosities, excessive energy input, the mechanical bonding between the composite coating and the substrate. In recent years, laser cladding technique has been developed and can avoid these disadvantages of the conventional surface techniques mentioned above by choosing optimal parameters.…”

High Chromium Fe-Cr-Mo-P-C Amorphous Coating Films Produced by Thermal Spraying Technique

“…So the corrosion resistance of the Fe 70 Cr 10 P 13 C 7 amorphous coating film did not enough for the practical applications such as the shaft sleeve of the slurry pump. 16) In the present study, high chromium Fe-Cr-Mo-P-C amorphous coating films containing up to about 35 at% Cr having excellent high hardness and high corrosion resistance have been produced by the thermal spraying technique with the cylindrical nozzle on shaft sleeve shaped cylindrical SUS304 substrates without cracking and peeling conditions. Corrosion tests of the sprayed films were also done under the severe immersion conditions of 35% hydrochloric acid.…”