Flame spraying is a thermal spray process that creates quality coatings using heat to melt materials that are usually in powder, ceramic rod or wire form. This type of thermal spray method is cost effective and one of the simplest ways to deposit coatings onto a substrate to provide impact resistance and protection from wear and tear.
The flame spraying process is fueled by a heat source that is created by a chemical reaction between a fuel of combustion and oxygen to create a stream of gas. The thermal spray material is then put into the flame in the form of a wire and compressed air is used to atomise the molten particles before propelling them onto the substrate. If you use a powder flame spray, the powder particles are softened by the flame before they are coated by the flame gases and accelerated through the nozzle.
Widely used as a cost effective method of protecting components and structures from damage and corrosion, flame spraying is used on a variety of different substrates. When equipment or a structure is required to have a high resistance, flame spraying is used to apply metallic and ceramic coatings so they are suitable for the environment they are being used in.
Flame spraying will is not as costly as many other forms of spraying due to the nature of the process and the finished quality of the coating.
With lower dust and fume levels than plasma and HVOF spraying, flame spraying can be used without a spray booth and also has lower noise levels.
Due to the nature of manual flame spraying, it is easier to coat equipment and components with complex geometry.
Compared to other thermal spray processes, flame spraying is made from a more simple design making it easier to use and it is suitable for manual use without the need for mechanised manipulators.
The coatings achieved by flame spraying are of a lower quality than those by other thermal spraying processes, however this is fine for environments which are less demanding. The coatings may have higher oxide levels for metal deposits, higher porosity and a lower bond strength.
Like most thermal spraying processes, flame spraying requires line of sight to the surface to coat. This means it is difficult to coat restructured surface areas or inner surfaces with a smaller diameter.
If you would like to find out more about flame spraying or the other quality coatings we provide for you and your business operations, please don’t hesitate to get in touch. Here at IRS, we are fully committed to providing durability and high performance through our range of applications.
Plasma spray is a form of thermal spray coating. It is the process of spraying a molten or heat softened material onto a surface to form a coating. The coating material, in the form of a powder, is injected into a very high temperature plasma flame which then heats the powder and accelerates it to very high speeds. When the now molten coating material comes into contact with the substrate (surface of the material which is to be coated) it then rapidly cools, bonding to the surface to form a coating.
Plasma is the term used to describe a gas that has been heated to such high temperatures that it ionizes and becomes electrically charged. The plasma spray gun achieves this by utilising the combination of a copper anode and tungsten cathode inside the gun, around and through which a gas (usually either argon, nitrogen, hydrogen or helium) flows. This causes the gas to become plasma where it is then forced out through a constricting nozzle where it is mixed with the coating substance in powder form. The powder then becomes molten and is fired out of the gun towards the substrate where it then cools and forms a coating.
When carried out correctly the plasma spray coating process is known as a ‘cold process’, as even though the plasma stream itself is very hot, the actual temperature of the substrate material that is to be coated can be kept relatively cool. This means that damage, metallurgical changes and distortion to the substrate material can be avoided and so more delicate substrate materials can be successfully coated using this process. However the extreme heat of the plasma also means that materials with very high meting points, such as refractory metals e.g. tungsten and ceramics e.g. zirconia, can used as coating materials.
There are a number of advantages including:
Although this is a very popular type of thermal spray coating, plasma spray does still exhibit a number of disadvantages which include:
For more information about the suitability of plasma spray coatings for your project, contact the experts at IRS Ltd today.