Tungsten Carbide WC-Co 88/12 Feedstock Properties
HVAF and HVOF Tungsten carbide coatings are sprayed with WC-Co agglomerated and sintered powder
Powders are available where cobalt is replaced with nickel.
The Properties of HVAF WC-Co Tungsten Carbide Coatings on Steel
WC-12Co thermal spray coatings are usually harder compared to coatings of WC-17Co as a result of higher tungsten carbide levels in the coating.
The tungsten carbide WC-12Co coatings are resistant to sliding wear, impact, abrasion and fretting at temperatures up to 510°C (950 °F), preferably in non-corrosive media. We recommend chromium carbide coatings for higher temperature applications.
Coatings that contain tungsten carbide protect substrates from the negative effects of fretting, abrasive grains, particle erosion and dynamic contact with hard surfaces.
These tungsten carbide coatings af steel can be used for abrasion-resistant coatings in dry, non-corrosive environments.
Although HVOF technology is frequently used for WC coating applications noticeable material oxidation and WC decomposition still occur during HVOF deposition.
The decomposition of WC-Co coatings is directly related to a high combustion temperature, usually more than 3,000oC (5,432°F), as well as the presence of oxygen in HVOF combustion products. This results in coating embrittlement and subsequent reduction of its service lifetime in conditions of abrasive and erosive wear.
Kermetico High-Velocity Air Fuel (HVAF) systems use gas fuel and compressed air for combustion at substantially lower temperatures and produce higher velocities than HVOF coating systems.
With the HVAF combustion temperature below 2,000oC (3,632°F), the surface temperature of Co-, Ni- and Fe-alloy particles usually remain near their melting point.
Depositing WC-Co coatings by the Kermetico HVAF spraying process eliminates WC coating embrittlement and improves its hardness and density.
It also reduces the production cost due to higher spray rates achieved and use of air instead of pure oxygen.
A distinguishing feature of the Kermetico HVAF process is that spray particles are heated but preferably not fused during spraying.
Kermetico HVAF WC-Co Coating Properties
|apparent metallographic porosity, %|
|bond strength of a tungsten carbide coating to carbon steel|
80+MPa @100 µm
|hardness range, HV300|
|hardness deviation from a target value, HV300|
|typical as-sprayed roughness|
|maximum working temperature of the coating|
A Typical Cross-Sectional Micrograph of a Kermetico HVAF WC-Co Coating
Typical Applications of HVAF WC-Co Coatings
Heavy Abrasive Wear and Erosion Resistance:
- Steel rolls
- Corrugating rolls
- Agricultural rasp bars
- Exhaust fans
- Conveyor screws
- Sucker rod couplings
- Thread bars
Uniform high hardness and ductility, low stress and porosity lead to a substantial increase of service life of parts protected with Kermetico HVAF WC-Co coatings in comparison with HVOF tungsten carbide versions.
Kermetico HVAF Equipment to Spray Tungsten Carbide Cobalt Coatings
Most Kermetico guns are good to spray WC-12Co Coatings. We started to design our equipment to excel in the application of tungsten carbide coatings.
- Convertible HVOF and HVAF equipment:
- Multi-purpose HVAF AK systems, with a range of spray guns:
- AK7 – a high-power gun for the thermal spray of large parts
- AK6 – a tungsten carbide coating gun to spray a balanced mix of parts in a job shop
- AK5 – a compact gun to spray smaller parts, thin walls and complex surfaces
- AK-ID – an 80 mm (3.15”) and larger internal diameter spray gun
- AK-IDR – a rotating ID gun to spray 4” (100 mm) and larger bores
- AK-HH – a handheld gun for on-site coating
- Additional equipment:
Kermetico, Inc. – HVAF and HVOF Material Science Excellence and Equipment Manufacturing Since 2006
We create equipment that helps material scientists, engineers, and business managers achieve their goals.
We have installed more than 60 Kermetico HVAF and HVOF systems in the USA, Europe, Japan and China.
Some of the systems are at work in Universities and National Labs, but most of them are used in production thermal spray shops.
We proudly design and produce our HVOF and HVAF thermal spray equipment in California and install it all over the world.
We also provide HVAF and HVOF thermal spray coating services for customers in the San Francisco Bay Area in California, USA.