Question 1

What is thermal spray coating?

Accepted Answer

It's a way of putting a hard, protective skin on a part by spraying it on. A metal, carbide, or ceramic is heated until it's molten or nearly molten, then blasted onto the component, where it flattens and bonds into a dense layer. You use it to fight wear, corrosion, erosion, and heat — or to build a worn part back up to its original dimensions.

Question 2

What's the difference between D-Gun and HVOF coating?

Accepted Answer

Both are thermal spray, but D-Gun (Detonation Spray) uses a controlled detonation instead of a continuous flame, which drives the particles in even harder. That produces an exceptionally dense coating — bond strength above 80 MPa, porosity under 1%, and hardness up to 1400 HV. HVOF uses a continuous supersonic flame and is excellent for dense WC-CoCr and similar carbides over larger areas. For the most demanding wear parts, D-Gun is the top tier.

Question 3

HVOF coating or hard chrome plating — which is better?

Accepted Answer

For wear protection, HVOF has largely replaced hard chrome. An HVOF tungsten carbide coating is harder, denser, and longer-lasting, and it avoids the hexavalent chromium that has made hard chrome an environmental and health problem regulators are phasing out. In aerospace, oil and gas, and heavy industry, HVOF is now the standard choice.

Question 4

Tungsten carbide or chromium carbide coating?

Accepted Answer

It comes down to temperature. Tungsten carbide gives the highest hardness and wear resistance but starts to oxidise above roughly 540°C. Chromium carbide is slightly softer but holds its hardness and resists oxidation up to about 870°C. So tungsten carbide for ambient and moderate heat, chromium carbide for hot-section and high-temperature wear.

Question 5

How is a tungsten carbide coating applied?

Accepted Answer

By thermal spray — D-Gun or HVOF. The part is grit-blasted first to give the surface a key, then carbide powder is fed into a high-energy flame that heats and accelerates it onto the part, where the particles flatten and build up a dense layer. It's sprayed slightly oversize, then ground or polished back to the exact dimension and finish.

Question 6

What size components can you coat?

Accepted Answer

It depends on the process. Detonation Spray and HVOF handle precision components and rotating parts; our Metalizing line takes large items up to 800 mm in diameter and 7 metres long. If you are unsure which process suits your part, send us the drawing and the duty it has to survive, and we will recommend the right one.

Property	D-Gun	HVOF	Metalizing
Bond Strength	Excellent (>80 MPa)	Very Good	Good
Porosity	<1%	<2%	5-15%
Coating Hardness	Up to 1400 HV	Up to 1200 HV	Up to 400 HV
Particle Velocity	Very High	Supersonic	Moderate
Substrate Heating	Minimal	Low	Moderate
Best For	Critical wear parts	Dense carbide coats	Large-scale coating

Coating Technologies

Detonation Spray Coating (D-Gun)

Key Advantages

Available Coatings

Tungsten Carbide (WC-Co)

Chromium Carbide (Cr3C2-NiCr)

Nickel Chromium (NiCr)

Ceramic Coatings

High Velocity Oxygen Fuel (HVOF)

Key Advantages

Available Coatings

WC-CoCr

Stellite Alloys

Inconel Coatings

Metalizing Process

Key Advantages

Available Coatings

Zinc Coating

Aluminum Coating

SS Overlay

How They Compare

Common Questions

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