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Monthly Archives: February 2019

 

22 
Feb

What is Flame Spraying?

flame spraying imageFlame 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.

How does Flame Spraying work?

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.

What is Flame Spraying used for?

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.

What are the advantages of Flame Spraying?

Cost effective

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.

Lower dust and fume levels

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.

Coat complex geometry

Due to the nature of manual flame spraying, it is easier to coat equipment and components with complex geometry.

Portable and easy to use

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.

What are the disadvantages of Flame Spraying?

Lower-quality coatings

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.

Difficult to coat restricted surfaces

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.

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Published Date: 22nd February 2019
Category: News


 

14 
Feb

Impeller Repair Services

At IRS we  carry out lots of Impeller repairs like the examples in the images below. We can apply coatings to neck ring areas or weld up Impellers like the examples below. These pictures are before and after shots of the same Impeller.

Why not Let IRS have a look at your Impeller and with a little tender love and care, it can look as good as the one below.

Contact us online or call 01704 896332.

 Impeller-Repairs-1 Impeller-Repairs-2

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Published Date: 14th February 2019
Category: Metal Spraying


 

01 
Feb

Plasma Spray Coatings

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.

How does Plasma Spray coating work?

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.

Top Uses

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.

Advantages

There are a number of advantages including:

  • Wide variety of materials that can both be coated and be used to form coatings.
  • Higher quality coatings can be achieved compared to other types of thermal spray processes.
  • A broad range of powder particle sizes can be used, typically between 5-100µm.
  • Well known process that is widely available and well understood.

Disadvantages

Although this is a very popular type of thermal spray coating, plasma spray does still exhibit a number of disadvantages which include:

  • The specialist equipment is expensive to buy at the outset.
  • Due to the high temperatures involved the internal components of the guns experience rapid deterioration and so must be replaced at regular intervals.
  • The high temperatures involved can result in carbide decomposition or excessive oxidation when spraying in air.

For more information about the suitability of plasma spray coatings for your project, contact the experts at IRS Ltd today.

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Published Date: 1st February 2019
Category: Thermal Spray Systems