Features of HVAF-ARC

       1) The spraying temperature of the HVAF-ARC spraying system is high, and the metal effect is heated to a liquid state by an active arc: the acceleration and atomization of the active air flow can produce fine spray particles, and the size of the atomized particles is 5-6 times smaller than that of conventional arc spraying , its speed exceeds the speed of sound, and the average particle velocity is several times higher than that of conventional arc spraying. As a result, a very dense and high-quality spray coating can be obtained, which has become the latest hot technology of thermal spraying. Compared with conventional arc spraying, this system has the following advantages in process performance:



    ①High deposition rate, about 75%;

    ② The coating is denser, with a porosity of about 1%;

    ③The spraying jet is more concentrated, the flight distance is long, and the spraying distance can be adjusted in a wide range, which improves the process adaptability;

    ④The coating is smoother and more uniform, and the surface precision is higher;

    ⑤ The speed of spraying particles is higher, exceeding the speed of sound;

    ⑥The sprayed particles are small and uniform;

    ⑦ The matrix is less overheated.

    2) HVAF-ARC spraying has good atomization effect

    It can also be found from the development of thermal spraying. With the upgrading of thermal spray equipment, the speed of particles continues to increase, and the quality of the coating continues to improve. Like ordinary arc spraying, HVAF-ARC spraying is a continuous and repeated melting-atomizing-deposition process. But in the atomization method, HVAF-ARC spraying is different from ordinary arc spraying: ordinary arc spraying adopts subsonic atomization, while HVAF-ARC spraying adopts supersonic active atomization. Compared with subsonic atomization, the supersonic atomization effect is good, the particles after atomization are fine and uniform, and the speed is high: the particles are in the decompressed combustion products, rather than moving in the air, which reduces the amount of particles caused by the atomization. Size reduction is prone to the possibility of oxidation. Therefore, the oxygen content in the HVAF-ARC sprayed coating is comparable to or slightly higher than that of the conventional arc sprayed coating, and the oxide film on the surface of each particle is thinner, which is beneficial to obtain a high-quality coating.

    3) HVAF-ARC has a reasonable reducing atmosphere

    Since the reactive gas propane or propylene used for spraying is adjusted to excess, this reducing atmosphere acts as a gas shield for the sprayed particles of the wire.