Properties of Coatings Obtained by Supersonic Arc Spraying with Aerosol Fluxing

Despite the undeniable advantages of electric arc spraying technique, it has disadvantages, such as burnout of alloying elements and a high content of oxides in the applied metal coating. The solution to this problem and neutralization of the negative effect of oxidation of the deposited metal by ambient oxygen is the use of aerosol fluxing while spraying. The article considers an effective technique for improving the physical and mechanical properties of a metallized coating based on aerosol fluxing. The essence of this technique is that an aerosol consisting of an aqueous solution of chemical inorganic materials is introduced into the torch of metal molten by an electric arc together with compressed air. The aqueous solution is poured into the hydraulic disperser connected to the metal spraying gun air channel. Aerosol fluxing makes it possible to deoxidize and alloy metal during arc spraying, thereby increasing the level of its properties. The results of topographic studies of metallized coatings are presented. The resulting coatings have a structure with grain sizes from 200 to 2500 nm, with both pronounced and barely noticeable boundaries between grains. It is established that when using aerosol fluxing during arc metallization, a finer-grained structure is formed in the coatings increasing their strength. The conducted metallographic studies have shown that the thickness of the metallized coating varies from 2490 to 2586 microns. The use of aerosol fluxing in arc spraying does not have a significant effect on the thickness of the applied coating. The study of the coatings microhardness shows that the use of aerosol fluxing with a flux consisting of Na 2 CO 3 , Na 3 AlF 6 , Na 2 B 4 O 7 makes it possible to increase these values by 1.6–1.9 times.