problem with SG100 plasma gun

[vetrinit]

Need experts opinion/knowledge
I have just started working with Metallisation commissioned APS/HVOF system with SG 100 plasma gun and Diamond jet MDJ2600 HVOF gun. Below are the problems I faced

1. Cathode (non vortex stabilized) getting worn out in short time and cathode mounting end i.e Cu with treads melting away. (Gun parameters current 700-800A, Primary gas Ar 40-50 NLPM, Secondary gas H2 1-2 NLPM). What could caused such early failure?

2. In the same SG100 gun while spraying Y2O3(PAC powder) could see the powder particles forming a trajectory at the gun exit and moving away from plasma axis eventually low melting of powders. Is it due to higher carrier gas flow or its because of gravity the powders particles coming out of flame. ( Carried gas 5 NLPM Ar and feeder RPM 5)

3. What are the recommended parameters to start with for Y2O3 coating with minimal porosity and complete melting with SG100 gun over graphite substrate?

Regards
Vetrivendan E.

[Vadim Verlotski]

Need experts opinion/knowledge
I have just started working with Metallisation commissioned APS/HVOF system with SG 100 plasma gun and Diamond jet MDJ2600 HVOF gun. Below are the problems I faced

1. Cathode (non vortex stabilized) getting worn out in short time and cathode mounting end i.e Cu with treads melting away. (Gun parameters current 700-800A, Primary gas Ar 40-50 NLPM, Secondary gas H2 1-2 NLPM). What could caused such early failure?

2. In the same SG100 gun while spraying Y2O3(PAC powder) could see the powder particles forming a trajectory at the gun exit and moving away from plasma axis eventually low melting of powders. Is it due to higher carrier gas flow or its because of gravity the powders particles coming out of flame. ( Carried gas 5 NLPM Ar and feeder RPM 5)

3. What are the recommended parameters to start with for Y2O3 coating with minimal porosity and complete melting with SG100 gun over graphite substrate?

Regards
Vetrivendan E.

I want to start with the third item. Thick Y2O3 coating on graphite can not be obtained in any way. Do not have to try. The only thing that you can obtain from the plasma gun SG100, - porous coating of Y2O3 on metal substrates.
The first and second points can assume the following: too high current for a very small flow of argon (hence the overheating of the cathode) - it is necessary to significantly increase the flow of argon (1.5-3 times). High consumption of argon will also capture particles of powder into the flame and increase their speed. In addition, it is possible that Y2O3 powder is too coarse. You can try the smaller fractions.

Regards

[loriolo]

Hi
I had many experiences with SG 100 gun, and I could say you, that this gun was designed to work with helium as secondary gas, and it work very well with this gas, but with H2, this gun do not perform so well, in all new systems sold with SG100 gun it was necessary to update another gun that perform better with H2 gas, I updated F4 gun on 3 new systems.

[vetrinit]

Thanks for the information Mr. Vadim Verlotski and Mr. Lugi.
Having know about this problems with SG100 would not have gone for it. Since this installation is new have to work with it for a while before up-gradation with F4 or 9MB. Can you plz suggest parameter window for this SG100 for coating ceramics like YSZ, Yttria and Alumina.

Regards
Vetrivendan