The Ductility of Kermetico Hard Tungsten Carbide Coatings

Kermetico AK-series HVAF equipment deposits ductile tungsten carbide coatings with a hardness of 1450-1600+ HV₃₀₀, less than 0.3% porosity, no cracking. VTT, Finland, CPRI, India, as well as other researchers support these claims and have published academic papers that support these findings.

But most of us believe that higher hardness results in a greater fragility. Is it true for Kermetico tungsten carbide coatings?

NO.

What makes HVOF sprayed WC-10Co-4Cr that brittle?

W2C, which forms in HVOF coatings in the oxygen-rich atmosphere at the 2800°C+ combustion temperatures.
This W2C is absent in HVAF coatings, making them ductile.
According to ITSC-2015 paper here, HVAF coatings have 1.5 times higher modulus of elasticity than HVOF specimens.
The team from India at the Central Power Research Institute (Bangalore) was using “scratching technique” for modulus determination, getting 420-460 GPa for different Kermetico HVAF coatings and about 260 GPa for HVOF coatings. They were scratching through the entire coating thickness in different directions.

Furthermore, there are publication and reports, directly comparing Kermetico HVAF WC-10Co-4Cr with HVOF counterparts (JP5000, DJ2600, K2). The HVAF AK coatings superiority in trials:

• Rubber Wheel test, Miller test, Pin-on-Disc test: 1.5-2.0 times
• Silt erosion and dry erosion: 5+ times
• Cavitation: 10+ times
• In the erosion test, the WC-10Co-4Cr Kermetico HVAF coatings performed better at a 90-degree angle of attack as compared to a 30-degree

These data have come from several sources.

These features result in superior cavitation and erosion test results for Kermetico HVAF coatings.
That coating quality means vast new market possibilities for Kermetico HVAF WCCoCr thermal spray applications.

Take a look at some of them at our “Applications” pages.

Kermetico HVAF Equipment to Deposit Ductile WC-10Co-4Cr Coatings

Kermetico designs and manufactures three families of HVAF thermal spray equipment.

• Convertible HVOF and HVAF equipment:
  • C7 – an HVAF/HVOF gun for large parts
  • C6 – a general purpose HVAF-HVOF gun
• Multi-purpose HVAF AK systems, with a variety of spray guns:
  • AK7 – a high-power gun for the thermal spray of large parts
  • AK6 – a universal 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
• Specialized HVAF S equipment:
  • SL – a specialized gun for spraying low melting point metals
  • SP – a dedicated gun for the most efficient precious metals’ deposition
  • STi – a specialized gun for the deposition of titanium and Ti-alloy coatings

• Additional equipment:
  • An HVAF grit feeder for the grit blast preparation of parts to reduce coating costs
  • A Gas Permeability Tester for an instant check of a coating through porosity

Kermetico, Inc. – Material Science Excellence, HVAF and HVOF Equipment Manufacturing and Thermal Spray Coating Services Since 2006

We create equipment that helps material scientists, engineers and business managers achieve their goals.

We have installed more than 60 Kermetico HVAF 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 HVAF thermal spray equipment in California and install it all over the world.

You can visit our R&D center in Benicia to meet our designers and see our HVAF and HVOF equipment in action.

We also deposit HVAF and HVOF thermal spray coatings for customers in North America – ourselves and through our network of partners.