Brief introduction of thermal spraying ceramic bar equipment, technology and materials

       Ceramic rod is a welding rod-shaped flame spraying material specially manufactured with ceramic rod flame spray gun. They are made by bonding different oxide ceramic fine powders with adhesive, extrusion molding, sintering, and processing.



The structure of the ceramic rod flame spray gun is similar to the wire flame spray gun, but the metal wire of the flame spray gun is replaced by a ceramic rod, and the wire feeding mechanism becomes a rod feeding mechanism. Because the diameter of the ceramic rod is larger, the diameter of the feeding rod is larger; because the melting point of the ceramic is higher than that of the metal, the power of the flame is larger, and the corresponding gas path and nozzle structure design should meet the needs of the ceramic rod spraying. When the ceramic rod is flame sprayed, the ceramic rod is passed through the tail hole of the spray gun into the gun body, and the mechanical transmission wheel in the gun sends it into the flame center of the nozzle at a certain speed, and is surrounded by high temperature flame about 3mm away from the nozzle mouth. Melting, the molten end of the ceramic rod is atomized into fine droplets by high-speed compressed air, and then sprayed onto the surface of the substrate to form a coating.



The ceramic rod spraying operation is cumbersome. When spraying large pieces or continuously spraying new rods, it is often difficult to convey and uniformly atomize the tail section of the rod material. The cost of ceramic rods is also high and the production efficiency is low. But despite this, ceramic rod flame spraying is still active for 50 years. Its main feature is that the end of the ceramic rod is fully melted in the center of the flame, and then atomized into fine ceramic droplets and sprayed onto the surface of the workpiece to form a coating. Therefore, the coating is dense, with low porosity and good bonding strength, and there is no boundary effect of the flame flow during powder flame spraying and plasma spraying, that is, a small amount of ceramic powder is not able to melt or is not sufficiently melted and exists in the coating, affecting the coating. quality.