B&B Coatings | Huddersfield

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Our experts on…Thermal Spraying

Thermal spraying can be a fantastic way to apply a coat to your component, but clients at B&B regularly ask our experts for advice on what the different kinds of sprays are and what their respective benefits and negatives are. Let’s start by explaining exactly what it is that makes each process different from each other.

HVOF
HVOF or High Velocity Oxygen Fuel uses a combination of heat and pressure to coat. Oxygen is mixed with either a liquid or gas and combusted in a chamber where it heats and expands until its forced out at supersonic speeds. HVOF was designed using jet engine technology and can produce velocities of MACH 3. Coating is ground up into powder and shot out at such high speeds it bonds with the metal. This forms a very high strength bond.

Flame Spraying
This follows the same principle of HVOF only at lower velocities. Heat is generated by combusting a fuel gas and oxygen mixture which heats up the coating. Coatings for flame spraying can be either wire or powders. The compressed air is used to propel the coating towards the component. Generally these coatings aren’t as good as HVOF in terms of bond strength and porosity levels but you can create a solid coating at a lower cost point.

Plasma Spraying
Plasma spraying is considered one of the more flexible thermal spraying techniques. It uses a DC electric arc in order to form a high temperature plasma gas. This in turn heats up the coating powder as it’s fed into the plasma jet. Inert gas is then fed into a torch which creates the velocity needed to bond the coating to the component. Plasma Spraying is especially good at producing coatings for materials with high melting points.

Arc Spraying
Arc Spraying is the thermal technique that often has the highest productivity rate. A DC electric arc is placed between two wires of coating material. These wires melt which form the spray material and compressed gas is used to compress atomize the coating material and propel it towards the component. This will often give you a better bond and porosity rate compared with flame spraying but can sometimes produce arc light, ozone and fumes.

This is just a broad overview on the different thermal spraying techniques. The experts here at B&B are keen to keep our clients as informed as possible so they can better make a decision on their coating needs. Get in touch today to see how we can help you.

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