Causes of oxides in Metco58NS coating

[thezombiesprayer]

Hi all

I have problems with clusters and a high percentage of oxides in my copper nickel indium (Metco 58NS) coating for the past few months.
We have tried to clean out hoppers, changing of the nozzle and electrodes and it seem to be slightly better.
But soon after, the percentage of oxides goes back high again.

What is the cause of oxides in Metco 58NS coating?
Due to dirty environment?
Powder settling issues if put too long?

Does anyone sieve the Metco58NS powder before spray?

Hope I can get some help to get rid of these oxides.

Thanks

thezombiesprayer

[loriolo]

Hi
you do not say what kind of gun do you use, for this powder is necessary, if you use a Metco gun, to use powder port with 2 PSA air injector, with a cross jet of 114 mm and 3,2 bar, in order to have more coating density and lower porosity...

[thezombiesprayer]

Hi
you do not say what kind of gun do you use, for this powder is necessary, if you use a Metco gun, to use powder port with 2 PSA air injector, with a cross jet of 114 mm and 3,2 bar, in order to have more coating density and lower porosity...

Hi

Sorry. I forgot to mentioned the hardware that I am using. We are using a Metco system, F4 gun. The powder port that we are using is of dia 1.8mm, 90 deg and powder port distance from centre is 6mm. not sure about the 2 PSA air injector that you mentioned. is it for another metco gun?

our cross jet distance is about 280mm and 40psi.
Is it too far to blow off unwanted particles at the substrate level?

We have tried to clean up the powder hopper and the powder port areas at the gun level. It seemed to lower the oxide clusters by a bit.
Our booth has bit of poor suction at times. does this also contribute to oxides as well?

Thanks

thezombiesprayer

[loriolo]

Well now your info are quite complete, if you use F4 instead of 9MB gun, you must change powder rate and or spray distance, since you can eliminate oxides doing little changes once a time, take in mind that copper oxidizes easily, if you do not have any enhancement, check the Argon line for little holes, because the air can be aspirated by venturi effect.