Study on the Preparation, Microstructure and Friction properties of Cold Sprayed Fe-based Amorphous Composite Coating

Abstract:

Amorphous alloy has a unique short-range ordered, long-range disordered atomic arrangement structure, with high strength, high hardness and excellent corrosion and wear resistance and other properties, has a strong application potential in the field of protective coating. The preparation technology of cold spraying layer, which is characterized by low temperature solid deposition, can effectively avoid the oxidation and crystallization of non-crystalline alloy materials in the spraying process, but the cold spraying technology depends heavily on the plastic deformation ability of powder. In order to improve the deposition and deformation performance of amorphous alloy particles under high speed impact, this paper innovated the liquid nitrogen-room temperature cycle cryogenic treatment method to pretreatment the Fe87.4Cr2.5Si6.8B2.4C0.9 amorphous alloy powder, and prepared the embedded composite coating of amorphous alloy particles on the 6061 aluminum alloy substrate surface by adjusting the technological parameters of cold spraying. The influence mechanism of cryogenic treatment on the deposition behavior of amorphous powder and the microstructure of coating was studied. The results showed that the coating thickness was only 6μm, and the amorphous particles were discontinuously distributed on the surface of the substrate. Only the amorphous particles with smaller particle size could have effective plastic deformation, but the crystallization rate was low during the deposition of the powder. The average thickness of the coating prepared by cryogenic amorphous powder was 67μm, and the amorphous alloy particles in the coating were uniformly distributed. The amorphous particles with larger particle size could also undergo effective plastic deformation, but the crystallization rate was higher during the powder deposition.6061 aluminum alloy substrate in the process of friction and wear of the main wear mechanism is adhesive wear and fatigue wear. Amorphous coating, the main wear mechanism of abrasive wear and use the original amorphous powder and cycle cryogenic processing powder preparation of amorphous coating is low, the quality of the wear of 6061 aluminum alloy substrate respectively quality wear rate of 15.7%, 11.8%.

Key words:Cold spray; Cyclic cryogenic treatment; Amorphous coating; Crystallization rate; Frictional wear property