HVOF Coatings

HVOF is a process that utilizes supersonic acceleration of coating material particles to several times the speed of sound (See the shock diamonds in the picture below). The tremendous impact energy of the particles fuses them to the base metal of the surface forming extremely strong coatings.

Why MBI HVOF ?

We apply HVOF coatings through a unique system that has even faster material particle velocities resulting in what is called Impact Fusion. The particles are practically forge welded to form the coating. Higher particle velocities and Impact Fusion result in denser, better bonded coatings. Compressive stresses within the coating ensure very high adhesion (even at thicker coatings). Conventional or other HVOF coatings have higher residual stresses which are in tension. This condition can cause cracking or dis-bonding. MBI's HVOF coatings are in compression. This condition results in better coating integrity, enhanced corrosion properties and improved thermal fatigue properties.

Typical Characteristics:

  • Surface Texture: from As-sprayed 90 - 450 (Ra) to Ground /Lapped extremely low (Ra)
  • Hardness, Macro: 1300 (DPH300)
  • Bond strength: Over 12,000 psi
  • Thickness: from .001” and up
  • No residual stresses
  • Porosity: virtually none

MBI’s HVOF process provides carbide & metal coatings of unsurpassed quality and wear life. The HVOF gun is essentially a liquid fuelled 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.

HVOF Carbide coatings contain higher carbide percentage than Clad-carbide methods, which makes them more wear resistant at lower thickness; thus, the process avoids excess waste and the higher cost associated with cladding.

Typical Applications

  • High strength Tungsten carbide.
  • Coatings for Rolls ( Various types, Chill, Laminator, Idler, Feed, etc.)
  • Release coating on Rolls, MBI’s Carbide - Traclon (Extreme non-stick)
  • Carbide coating on Knife edges to prolong sharper edge and longer wear.
  • Extreme wear areas, such as:
  • Hard-facing Granulator Rotors
  • Pump housings & Impellers
  • Shredding components
  • Mandrels, Extruders
  • Tracks & screw conveyors
  • Blowers & Fan blades
  • Mixing & Auger parts
  • And many more!

MBI’s HVOF coatings are very dense, extremely well bonded and free of all oxides and tensile stresses inherent in coatings provided by other coating processes. Consequently, HVOF coatings perform better in service.

HVOF wear resistant coatings typically out-perform the wear life of hard chrome plating, hardening anodizing and other hard facing techniques by many folds.

The success of HVOF & Thermal sprayed coatings in the aircraft industry (the largest market) has led to applications in other markets including: plastic, textile, steel, pulp /paper, chemical, utilities, etc.

Cost-effective thin coatings on production equipment not only provide increased service life, but also allow design in which expensive materials can be replaced by cheaper ones, then coated for better performance; such as the case with HVOF coatings.

Call (803) 313-9292 or click here to contact MBI for more information.