Need advice on unmelt particles in Metco 58 coating

[vivian]

I have problem with unmelt particles in Metco 58 coating. The poosity % is 1 to 2 and not associated with the unmelt particles.

The coating is sprayed with 9MB gun without cross air jet.
Will the cooling affect? And i am thinking to use sieved powder.

Kindly advise how to reduce the unmelt particles. Thanks.

[Bler]

You can increase the power if the oxide requirement is not too high(current first, if not work,then gas ).9M has a high power,unmelted may not be a big problem.

[loriolo]

Hi Vivian
Try first a check for geometry and parameters (GH nozzle, cross jet 114 mm, etc. if you use 9MB gun) and see if everything are Ok, this powder is difficult to set, because is a copper/nickel/indium powder and Cu oxidize easily, so if everything are ok, then tray reducing powder rate from 44 maybe to 42gr/minute…40 and so on