NiCrBSi coating by DJ2600

[Zhao Yun]

Hi everyone,

I'm developping the NiCrBSi coating with DJ-2600 gun, and I met one problem with the air cap in the gun.

After sevelal passes, there deposited much coating on the surface on of air cap like below.  
https://i.postimg.cc/d3KvKpMH/2022121174346909.png

Parameters are: H2 600NLPM, O2 200NLPM, Shroud gas 300NLPM

Could U help me?

[Vadim Verlotski]

Your problem is that the NiCrBSi particles get so hot inside the nozzle that they melt and stick to the nozzle wall. In order to solve the problem, the particles do not have to be melted inside the nozzle, but only outside it. This is done on the one hand by means of burner settings (less fuel gas and more inert gas) and on the other hand by selecting the particle size (coarser powder or less fines in the powder mixture).

[Zhao Yun]

Your problem is that the NiCrBSi particles get so hot inside the nozzle that they melt and stick to the nozzle wall. In order to solve the problem, the particles do not have to be melted inside the nozzle, but only outside it. This is done on the one hand by means of burner settings (less fuel gas and more inert gas) and on the other hand by selecting the particle size (coarser powder or less fines in the powder mixture).

Thanks for your suggestion. "less fuel gas and more inert gas" does the inert gas mean shroud gas? 

It's really appreciated that you can share with me your parameters if possible.

[Vadim Verlotski]

Try using 500 NLPM shroud gas instead of 300 NLPM shroud gas. Maybe this alone will solve the problem. If not, using a coarser grained powder will certainly help.

[Zhao Yun]

Try using 500 NLPM shroud gas instead of 300 NLPM shroud gas. Maybe this alone will solve the problem. If not, using a coarser grained powder will certainly help.

OK，I'll try it and thanks

[gerdogan]

Hi everyone,

I'm developping the NiCrBSi coating with DJ-2600 gun, and I met one problem with the air cap in the gun.

After sevelal passes, there deposited much coating on the surface on of air cap like below.  
https://i.postimg.cc/d3KvKpMH/2022121174346909.png

Parameters are: H2 600NLPM, O2 200NLPM, Shroud gas 300NLPM

Could U help me?

Hello Zhao,

I could not open the image you posted but guessing the inner nozzle is clogged. Please consider increasing carrier gas and checking the powder injector to see if it is placed correctly and not worn.

Regards
Garip

[Zhao Yun]

Hi everyone,

I'm developping the NiCrBSi coating with DJ-2600 gun, and I met one problem with the air cap in the gun.

After sevelal passes, there deposited much coating on the surface on of air cap like below.  
https://i.postimg.cc/d3KvKpMH/2022121174346909.png

Parameters are: H2 600NLPM, O2 200NLPM, Shroud gas 300NLPM

Could U help me?

Hello Zhao,

I could not open the image you posted but guessing the inner nozzle is clogged. Please consider increasing carrier gas and checking the powder injector to see if it is placed correctly and not worn.

Regards
Garip

Yes, you are right the nozzle is clogged. I have tried to increase the carrier gas from 12.5NLPM to 16NLPM and 25NLPM, the bigger carrier gas the more concentrated flame flow,but the build up in nozzle is not improved. The powder injector is correctly assembled and not worn.