Plasma spraying requirements for powder feeders

       A powder feeder is a device that feeds spray powder material into a plasma jet. It is one of the important components of the plasma spraying equipment system.



     The requirements for the powder feeder are as follows:

    (1) Uniformity. In the continuous feeding process, the powder feeding amount should be uniform.

    (2) Sensitivity. The powder can be delivered immediately when it is opened, and it should be stopped immediately when it is closed.

    (3) Adjustment. The powder feeding amount can be continuously adjusted in a wide range, and the adjustment is convenient.

    (4) Sealing. When the powder air passes through the powder feeder, there should be no air leakage in the powder feeder, otherwise it will affect the stability of the spraying process specification and even cause powder blockage.

    (5) Good reproducibility. High reproducibility of powder feed rates in continuous, long-term automated spraying operations. It can provide a reliable guarantee for the reproducibility of the sprayed products, especially the coating thickness.

    (6) The powder feeding gas is inert. The powder feeding gas is best to use argon, but also nitrogen, so as not to affect the properties and hydrodynamic properties of the plasma jet.

    (7) The particle size range of the powder that can be transported is wide. Modern automatic control powder feeders can deliver powders of 2μm ~ 200μm particle size, and the powder feeding rate is 100/h ~ 8kg/h. For spraying ceramic coatings, being able to feed fine-grained powders smoothly is very beneficial for improving powder deposition efficiency.

    (8) The powder container is transparent and visible. The powder feeding tube adopts an antistatic tube to prevent the powder from being blocked due to the static electricity that may be generated during the powder flow.

     On the premise that the powder feeder meets the above requirements, the structure should be simple and reliable.