Activated Combustion HVAF (AC-HVAF) spraying provides efficient deposition of metallic and carbide coatings using solid particle spray technology. Oxidation and thermal deterioration of sprayed materials is significantly reduced, resulting in improved quality of coatings. Resistance of different WC-Co and WC-Co-Cr AC-HVAF coatings to abrasive wear was investigated using ASTM G-65 test. It was found that the AC-HVAF hardware setup, type of fuel gas and spray parameters affected deposition efficiency but not wear resistance of coatings. Herewith, the method of powder manufacturing revealed significant influence on coating wear resistance. The AC-HVAF sprayed coatings were compared to HVOF-sprayed counterparts, as well as to hard surfacing and chrome plating. The AC-HVAF sprayed coatings were efficient in competing with modern surfacing technologies in many industrial applications.

In Activated Combustion HVAF process, coatings are formed of powder particles, heated and accelerated by high-velocity jet of air and gaseous fuel combustion products. A distinguished feature of the process is that spray particles are heated below their melting point while accelerated to velocity well above 700 m/s. Such spray scheme appeared beneficial for deposition of cemented carbides, in particular, WC-based composites. Dense, practically non-oxidized neither heat-deteriorated coatings were formed. Spray rates from 1 to 25 kg/hr were achieved without decline of coating quality or deposition efficiency. Specific coating structure resulted in noticeably improved resistance to fatigue at high level of stresses.

HVAF Arc process deposited coatings of dual wire stock, fused by an electric arc and atomized by a high-velocity jet of air and gaseous fuel combustion products. The HVAF jet was generated in toroidal chamber, where a hot catalytic insert activated the combustion process. Such atomization produced fine, 5-20 micron, spray particles accelerated to over 200 m/s. Excess of fuel in the arc zone prevented rapid oxidation of fused material. The process is specifically beneficial for deposition of high-quality coatings of aluminum, corrosion resistant nickel-base alloys and hardface Fe-Cr-B-C cored wires.

Activated Combustion HVAF Spraying (AC-HVAF) involves a jet of air-fuel combustion products to deposit coatings of metallic and carbide powders. In the process, spray particles are heated below their melting temperature while accelerated to velocity typically 700-850 m/s, forming a coating upon impact with a substrate. Extremely low oxygen content and high density are distinguished features of the AC-HVAF coatings, resulting in their excellent performance under conditions of severe wear and corrosion. Besides new level of coating quality, the AC-HVAF process demonstrates outstanding technological efficiency and spray rates 5-10 times exceeding those of the HVOF counterparts. The paper presents results on characterization of selected metallic and carbide coatings and describes their applications.