High-speedFlame SprayThe core of the HVOF equipment is the spray gun, which consists of three parts: the combustion chamber (capable of fully heating and accelerating the spray material particles), the Laval nozzle (capable of accelerating the flame to supersonic speeds), and the isometrically long nozzle (capable of fully heating and accelerating the spray material particles).
Supersonic Spray CoatingBoasting high hardness, low porosity, low surface roughness, excellent wear and corrosion resistance, this material holds great potential in industrial applications, particularly in anti-corrosion and wear-resistant materials. The supersonic arc spray process is highly flexible, allowing for the application of high-performance coatings across a wide skill range. Once developed, the equipment has been widely adopted.
This hypersonic coating process requires a high level of skill from the operator, typically performed by experienced technicians to ensure the coating effect. When conducting hypersonic coating, the following process flow should be followed:
Surface Cleaning: Primarily uses mechanical methods such as steel balls, supplemented by alkaline cleaning solutions to remove rust and oil污 from pipeline surfaces and other loose layers. Cleanliness reaches Sa3 grade to ensure a firm bonding foundation for ultrasonic coating.
2. Surface Roughening: Common methods include sandblasting and electroprocessing, which serve to enhance the mechanical bond between the coating and substrate. Standard roughness ranges from 6.5 to 25.
3. Base Coating: The expansion coefficient of the base layer is very close to that of the substrate, primarily to enhance the bonding strength and thermal shock resistance of the working layer.
4. Spray Layer: The working layer is on the outer surface, in direct contact with the smoke. The spray coating formed by the supersonic spraying equipment boasts excellent resistance to temperature corrosion and abrasion.
5. Sealing Treatment: After the coating is formed, it has a certain porosity, especially permeable porosity. Applying a high-temperature, wear-resistant, and corrosion-resistant sealing coating to seal the nozzle gaps of the working layer can enhance the performance of the hypersonic spray coating.
Based on the principle of supersonic spraying, the performance of the coating is determined by the state of the particles before deposition, including their speed, temperature, and melting state. Particle speed plays a crucial role in the coating's performance.
When particles impact the surface, high speed can create greater impact, with particles exhibiting strong deformation capabilities, which is beneficial for enhancing the adhesion and density of the coating. The surface characteristics of supersonic spraying are due to the high particle velocity, which has been widely applied in the industry.
