How Does Thermal Spray Work?

Coating materials are fed into a “gun” where they are heated to a molten or semi-molten state by electric or combustion energy.

High-pressure gas/air atomizes and propels the heated particles to a substrate that has been cleaned and prepped by abrasive grit blast. The heated particles impact the surface and flatten, which bonds them to the substrate where they build to create a dense, tightly-bound coating.

The Benefits of Thermal Spray Coatings


  • Low porosity
  • Wide variety of materials
  • Good adherence to substrate


  • Low permeability
  • Excellent corrosion or wear resistance
  • Reliable, long-lasting protection

While welded overlays have been used for many years, improvements in Thermal Spray equipment and process controls offer bond strengths and thickness potentials that rival welding. Added benefits of thermal spray are the relative smooth and consistent surface finish “as sprayed” allowing for quicker and more efficient post-processing to final size. Additionally, there is no heat affected zone (HAZ) associated with thermal spray. Because of the limited temperature exposure of thermal spray (<300°F), substrate strength and temper characteristics are not altered.

Ellison Surface Technologies’ High Velocity Oxygen Fueled (HVOF) coating method uses tightly controlled processing to apply an array of coatings, such as tungsten or chromium carbide, in place of hard chrome.

Some of the HVOF benefits are:

  • Reduced oxide content
  • Reduced solutioning of carbides
  • Neutral or compressive stress
  • Smother as-sprayed surface
  • True coating uniformity
  • Tensile band strength >10,000 psi.

Thermal Spray Coatings adhere to a wide variety of substrates. Their low permeability provides long-lasting protection against corrosion and wear. Thermal spray coating methods include HVOF, Plasma, Flame Spray and Electric Arc.

Flame Spray
Flame Spray – a low cost, mature
coating technology
Plasma Spray
Plasma Spray – combines gases and
electrical power to achieve high temperature
capabilities with a broad base of materials,
including ceramics
Electric Arc Spray
Electric Arc – a high capacity, medium
cost technology good for a wide range of
materials possibilities
High Velocity Oxy-Fuel
HVOF – state-of-the-art, high velocity
process of dense, well-bonded surface

What is a Thermal Spray Coating?

Thermal Spray Coatings Product Specifications