HVAF 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.
For more on the HVAF process, Click Here.
If you have any questions regarding your particular application or for more information on our equipment or consumables, call us on 07 3823 1004 or email us via our contact form.
