Thermal Spray Aluminium Coating is a technology widely applied in many industries around the world. Typically electronic, aerospace, mechanical, automotive industries to prevent corrosion and significantly improve the service life of the equipment. This process involves heat to create a protective coating of part surfaces with a material with custom properties. For an overview, this article will provide the basic information on Thermal Spray Aluminium.
Thermal Spray Aluminium Coating: Concept, characteristics and classification
Thermal Spray Aluminium Coating technology is an effective solution to protect parts and surfaces from high temperatures, corrosion and restore elements that have been corroded. 4 common types of thermal spray: Arc spray, HVOF, Plasma Spray and Combustion Spray. The Thermal Spray Aluminium method and coating materials are selected according to the surface characteristics and technical requirements. Find out more details in the sections below.
What is TSA – Thermal Spray Aluminium Coating? The purpose of thermal coating
Thermal Spray Aluminium Coating is an industrial coating process with different techniques. Still, all include a heat source (flame or other sources) and a coating material in powder or wire form, which is melted into droplets and sprayed onto the surface at high speed, forming a uniform coating, protecting the surface from corrosion, abrasion and environmental influences.
Thermal spray coatings also help improve, restore and enhance the surface quality of materials commonly used in the electronics, aerospace, mechanical and automotive industries.
This technology can produce coating layers with various thicknesses and good adhesion, capable of operating over a wide range of temperatures, coating speeds and atmospheric conditions. Therefore, spray coating allows application with a rich source of materials compared to other surface coating technologies.
Classification of Thermal Spray Aluminium – Which process is fit for your needs?
Currently, there are many Thermal Spray Aluminium Coating processes developed and applied in different fields. However, the four most common processes are two-wire arc, HVOF, plasma injection, and combustion (flame) injection. The specifics of these heat sprayers are as follows:
- Twin-wire arc: This Thermal Spray Aluminium method uses an electric arc of about 5000 degrees Celsius between two electrical conductors to melt the material. The compressed air pushes the molten metal particles to the substrate surface. High temperature and velocity combination results in a coating with high adhesion and coverage rate and low surface temperature. There are many coating applications for this process, such as anti-wear, anti-corrosion, component repair and anti-fraying. The system also has the advantage of being portable and fast, which can be used for jobs on site.
- HVOF: High-velocity oxygen fuel (HVOF) coating is a Thermal Spray Aluminium Coating process used to improve or restore the surface of a part. In this process, fuel and oxygen are mixed, injected into the combustion chamber and ignited continuously. The gas generated in the combustion chamber has exceptionally high temperature and pressure and is ejected through the nozzle at a supersonic speed (usually >1000m/s). The powder is injected into a high-velocity gas stream and pushed onto the surface to be coated. The result is a coating with low porosity and high bond strength to the base material.
- Plasma spray: The plasma coating process involves spraying molten or semi-molten powder onto the surface of a part to create a coating. The coating material is injected in powder form into a high-temperature plasma flame. It is rapidly heated and pushed to the surface of the part using a carrier gas. Plasma spray coatings typically use higher temperatures and lower velocities than HVOF, allowing a more comprehensive range of coating materials to be applied, including ceramics. The result is a thick coating with low porosity and high bond strength, which offers many benefits, such as corrosion resistance.
- Combustion spray: It is considered the first Thermal Spray Aluminium Coating method and has been widely used in many industries for over 100 years. The flamethrowing process uses an oxy-acetylene flame to apply a thermal coating. The heat from the flame melts the coating material, and the compressed air pushes it onto the coated product. The flame blasting process is also another “cold process” due to its relatively low operating temperature.
Features of Thermal Spray Aluminium Coating – the benefits of coating
There are many different coating processes, but Thermal Spray Aluminium Coating all have the following things in common:
- Spray coating materials with a higher melting point than the substrate
- Spray coating materials that are not metal compatible with the surface
- Wide choice of coating materials: steel, stainless steel, nickel alloys, pure metals (such as aluminium, zinc and copper), cermets, carbides, polymers and plastics
- Apply with different coating properties and in a variety of thicknessesrestore parts and material details quickly instead of replacing them.
- Extend the life of the components
- Applied both manually and mechanically.
- Good adhesion coating layer, allowing the part to withstand heavy operations or harsh abrasive environments.
The Thermal Spray Aluminium Coating process has been widely used for many years in all industry and engineering fields to protect and renovate structures. Spray coating equipment and techniques are also constantly improving, expanding the range of potential applications for Thermal Spray Aluminium. Each method has its characteristics, advantages, and disadvantages, which will be the optimal solution for different cases. Therefore, it is essential to understand the problems related to coating spraying for evaluation and selection.