Too many small particles in my coating

[devil72]

Dear all,

I hope you are all doing fine in this unforgettable year 2020.

I sprayed 2 different WC10Co4Cr powder with a HVAF system, one is 10-38um and another I user a bimodal 5-30um power which contains 40% nano sized WC.

But for both powder, WC grain size / distribution in coatings is not as good as expected while WC grain fineness homogeneity in powder is much better.

What could possibly cause so many heterogeneity grains in coatings ? Too much heat?

Thanks a lot~

       

[Vadim Verlotski]

Dear all,

I hope you are all doing fine in this unforgettable year 2020.

I sprayed 2 different WC10Co4Cr powder with a HVAF system, one is 10-38um and another I user a bimodal 5-30um power which contains 40% nano sized WC.

But for both powder, WC grain size / distribution in coatings is not as good as expected while WC grain fineness homogeneity in powder is much better.

What could possibly cause so many heterogeneity grains in coatings ? Too much heat?

Thanks a lot~

Hi,
HVAF coating process has no influence on the WC particle size in the layer (spraying temperature and time are not sufficient for grain growth). These particles remain in the coating just like in the powder. By the way, I don't see any difference between your two powders.

Regards
Vadim