HVOF Coating Process

High Velocity Oxy-Fuel

The HVOF process preheated, melted materials are used to produce hard facing coatings.  For this reason, HVOF is useful on surfaces that may vary in shape and size.  MBI Coatings has a well equipped facility for all types of coatings including high end HVOF. Because of this, we can help you protect your components against wear and corrosion. HVOF has low porosity and can be used in variable thickness.  It can also deposit much more quickly than other processes.  HVOF is best used for creating a thermal barrier, protecting against wear and abrasion, preventing corrosion, applying carbide or ceramic coatings, and preventing electric charges and static build up.

HVOF spray is useful in industrial markets including textile, steel, plastic, paper/pulp, chemical and power generation.  By using a HVOF spray application, the possibilities are nearly endless.

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High-Velocity Oxy Fuel Coating Process

How it Works

HVOF (High Velocity Oxy-Fuel) utilizes supersonic acceleration of coating material to several times the speed of sound (See the shock diamonds in the picture). As a result, the tremendous impact energy fuses the coating particles to the surface of the part to form an extremely strong coating. At that point, both kinetic and thermal energies are combined in a very effective fashion.

At once, fuel and oxygen are fed into the spray gun where they’re ignited in the internal combustion chamber providing the energy source for this unique coating system. The desired material in powder form is injected into the stream from a controlled feeder.  Immediately, it gets heated and accelerated as it’s exiting the nozzle. The material stream reaches velocities of several times the speed of sound as it impacts the work surface to form a solid homogenous coating. Shock diamonds in the spray stream can be observed in front of the spray gun nozzle.

The MBI Difference

At MBI, we apply HVOF coatings using a unique system that has even faster material particle velocities, resulting in what is called “Impact Fusion”.   For starters, the particles are practically forge welded (heated and then hammered together) onto the surface and onto each other to form the coating. In fact, higher particle velocities and Impact Fusion result in denser, better bonded coatings. Because of this, compressive stresses within the coating ensure very high adhesion (even at thicker coatings). Conventional or competitive HVOF coatings have higher residual stresses which are in tension. As a result, this condition can cause cracking or dis-bonding. However, MBI’s HVOF coatings will not dis-bond because they are in compression. In the end, better coating integrity, enhanced corrosion properties, and improved thermal fatigue properties are the final products.

Without a doubt, MBI’s HVOF process provides carbide & metal coatings unsurpassed quality and wear life. Essentially, the HVOF gun is a liquid fueled rocket running at high pressure. It imparts extremely high velocity molten coating particles. This velocity is much higher than other application methods. Higher velocity means higher quality coatings in terms of bond, wear, and corrosion.

Common Applications

  • High Strength Tungsten Carbide Coatings

  • Coatings on Roll Faces

  • Extreme Non-stick Surfaces

  • Hard-facing Granulator Rotors

  • Pump Housings & Impellers

  • Mandrels

  • Shredding Components

  • Extruders

  • Tracks & Conveyors

  • Screw Shafts & Augers

  • Blowers & Fan Blades

  • Mixer Parts

  • Turbine Shaft Surfaces

Key Advantages

  • Out-performs the wear life of hard chrome plating, hardening, anodizing, and other hard-facing techniques.

  • Very dense, extremely well bonded, and free of all oxides and tensile stresses inherent in coatings provided by other thermal spray coating processes.

  • Better wear resistance at lower thickness.

  • Thin HVOF coatings on production equipment provide increased service life.

  • Extremely effective against wear and corrosion.

Let’s Work Together

Whether you need to enhance the performance of your equipment or repair worn-down surfaces, MBI Coatings can help. Put our advanced surface engineering to work in your business.

Contact us today to learn more.

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