Hi Sam
to the Surface Engineering Forum.
Sorry, no practical experience with Metco 320NS through F4 gun. It would help to know set-up and parameters (Sulzer Metco recommended parameters or other?) used.
If your deposit efficiency is very poor as it sounds from your description, it would seem as though your powder particles are not being heated enough. This could be influenced by a number of parameter settings (gas flows, power, feed rate, spray distance etc.). If you are using equipment in good condition and parameters recommended by Sulzer Metco you should not really be having this problem. Not saying necessarily that SM parameters are optimal or best for your application, but a good starting point for a fairly balanced coating (coating quality and efficiency).
Anybody with 320NS/F4 experience? your comments would be appreciated