What are the forms and spraying methods of supersonic spraying materials?

Supersonic spraying, also known as high-speed flame spraying. As a new type of surface protection and surface strengthening technology, high-speed flame spraying technology has developed rapidly in the past 20 years and has become a very active branch in the field of metal surface engineering.

Using flames as a heat source, metal and non-metal materials are heated to a molten state, and a mist flow is formed under the drive of high-speed airflow, which is sprayed onto the substrate. When the tiny molten particles sprayed collide with the substrate, plastic deformation occurs, forming a sheet-like stacked deposition coating. This process is called flame spraying. In equipment maintenance, it is used to compensate for surface wear of parts and improve performance.

According to the form of the spraying material, flame spraying can be divided into powder flame spraying, stick flame spraying, etc; According to the form of spraying flame flow, it can be divided into ordinary flame spraying, supersonic flame spraying, gas explosion spraying, etc.

Common flame spraying methods include acetylene oxygen flame powder spraying, acetylene oxygen flame wire spraying, etc. The acetylene oxygen flame powder spraying equipment is simple, can be installed on site, and is suitable for equipment maintenance.

The porosity, microhardness, and quality loss of WC_12Co and Cr3C2-25NiCr carbide metal ceramic coatings were measured during the wear process using supersonic flame spraying technology. The relationship between coating wear quality loss and coating type and structure was explored. The shape of the coating wear surface was observed using scanning electron microscopy, and the wear failure mechanism of the coating was analyzed.

Supersonic flame is the high temperature generated by the combustion of hydrocarbon gases such as propane, propylene, hydrogen, and high-pressure oxygen in a combustion chamber or special nozzle. High speed combustion flame flow, with a flame velocity of over 5 Mach (1500m/s).

It is commonly referred to as HVOF (High velocity oxygen fuel). By axially feeding the powder into the flame, the sprayed particles can be heated to a molten or semi molten state and accelerated to speeds of up to 300-500m/s or even higher, resulting in high-quality coatings with high bonding strength and density.

Supersonic flames have high velocities but relatively low temperatures. WC Co hard alloy can effectively control the coating during the spraying process. The coating not only has high bonding strength, but also is dense and has superior wear resistance. The wear resistance is significantly higher than that of plasma spraying layer, equivalent to explosive spraying layer, and also exceeds that of electroplated hard chromium layer and sprayed melt layer. It is widely used.