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Lawrence Galterio

How to spray Tantalum carbide powder on graphite?

Allan Ashworth  Follow

You need a metal for that. Only metallic binders allow the plasma spraying of carbides. Since you want to apply this to graphite, you need a metal with the lowest possible thermal expansion coefficient. The best choice would be metallic tantalum because it would be most compatible with tantalum carbide powder and graphite substrate.
The important advantage of tantalum as a binder is the fact that this metal is well plastically deformable.
Another interesting variant would be metallic tungsten, which has even lower thermal expansion. Unfortunately, tungsten is extremely hard and that makes it much less attractive than tantalum.

To get a flowable spray powder from fine-grained TaC and Ta powder you need a spray dryer and a vacuum oven. The manufacturing process should look like this:
Submicron powders TaC and Ta are wet mixed together (for example 80% TaC + 20% Ta) and this suspension with added organic binder is spray dried. This produces an agglomerated mixed powder with a grain size of 10-50 μm, which after sintering in vacuum (1300-1500°C) is suitable for plasma spraying.

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Deevan Dilpat Rai  Follow

Hi Dvn
I wounder if you still want to use plasma spraying or you can use another technique of coating to get that thickness.
Do you need to have a "pure" TaC or you can apply organic binder?
Could you please give some details about the application?

Regards
Gobara

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Martin Ivers  Follow

Vadim Verlotski Thank you for the information.


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