| Fe-based amorphous alloys present outstanding performances such as high strength, high hardness, excellent wear resistance and corrosion resistance, but they have not been in a wide range of application because of the limitation of the preparation conditions. Using advanced thermal spray technology to prepare the surface of amorphous alloy coating is an important direction of development. Fe-based amorphous alloys as a new type of surface protection coating material have a broad application prospect because of the excellent properties. Fe-based amorphous alloy coating(containing Cr、Mo、B、C、Y)was deposited by thermal spray technology. Microstructure and properties of Fe-based amorphous coating deposited by detonation gun spraying technology have been studied by means of X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), micro-hardness tester and wear resistance experiments. Structure and properties of Fe-based amorphous alloy coating by detonation gun spraying technology have been mainly studied, the impact of different loads on friction and wear properties of the explosion spraying coating was systematically investigated, and the effect of heat treatment on the structure and properties of the explosion spray coating was studied. In addition, the thermal spraying technologies on microstructure and properties of Fe-based amorphous coating were also studied in this paper. The main conclusions are presented as follows:(1) Fe-based amorphous alloy coatings prepared by detonation gun spraying process and HVOF process present higher micro-hardness and more compact structure with typical layered microstructure; The alloy coating remained the chemical composition of the thermal spray powder; Fe-based amorphous alloy coatings prepared by detonation gun spraying process present more compact structure with lower porosity of2.1%, higher micro-hardness with the highest hardness of1201.8HV and the average hardness of1095.6HV; Fe-based amorphous alloy coating and substrate were combined with mechanical combination, and the bonding strength is up to30MPa. (2) Fe-based amorphous alloy coatings prepared by detonation gun spraying process present more excellent wear resistance than that of the iron-based amorphous alloy coatings prepared by HVOF. Fe-based amorphous alloy coating prepared by detonation gun spraying process takes shorter time to achieve stable friction coefficient, and it has a more stable friction and wear behavior; Fe-based amorphous alloy coatings prepared by two kinds of spraying process achieve more stable friction coefficient, more stable friction and wear behavior and the wear resistance of about5times than Q235steel substrate material.(3) The wear mechanism of Fe-based amorphous alloy coatings deposited by HVOF was mostly fatigue wear. However, wear mechanism of detonation gun thermal sprayed coatings is the combination of adhesive wear and abrasive wear, and the main wear mechanism is adhesive wear.(4) Fe-based amorphous alloy coatings prepared by detonation gun spraying process showed a better corrosion resistance in3.5%NaCl solution than Q235steel substrate material; The wear loss of the Fe-based amorphous alloy coating increased and the average friction coefficient of the Fe-based amorphous alloy coating first decreased and then increased with the increase in normal load.(5) The DSC showed that the supercooled liquid region of Fe-based amorphous alloy coatings prepared by detonation gun spraying process began at566.9℃and ended at650.6℃; According to XRD patterns, the heat treated coatings with the temperatures lower than crystallization temperature had an amorphous structure; When the annealing temperature was600℃, Fe-Cr phase began to crystallize; The amorphous phase will crystallize after heat treatment at700℃and the predominant crystalline phases precipitated were Fe rich phase, Fe2B and Fe23(C,B)6hard phase and Fe2O3phase.(6) Fe-based amorphous alloy coatings prepared by detonation gun spraying process showed more dense structure, decreased porosity, increased micro-hardness and better wear resistance with the increase of heat treatment temperature, and600℃was the best; The wear behavior of the heat treated coatings with the temperatures lower than crystallization temperature was changing from adhesive wear to abrasive wear; When the annealing temperature was700℃, the microhardness of coating increased, but its brittle was greater, then the wear behavior changed to the mixture of the two wear mechanisms. |
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