How do I do Bond Coat Selection?

[RV_DMG]

How to configure difference between using a bond coat material selection, Where I have options available as wires of NiAl 95/5, NiAl80/20 & NiCr 80/20.

Please suggest with some points of difference to make this selection easy. I have many applications where different materials to be sprayed but due to higher thickness bond coat needed to be applied.





Thanks

Ravi

[alaskangrown]

If you are permitted to use any of the materials you listed I would use 95/5. I apply that material to a thickness of 0.060-0.100 in some cases without loss of bond.
Since NiCr has Cr, I would stay away from it if given the option due to OSHA regs.
The bond coat is only providing a surface finish for the top coat to be adhere to in most cases. It really comes down to what role the top coat is playing. 95/5 should have a bond strength of about 5 - 6kpsi but it can reach 8kpsi.

[loriolo]

Hi ...
what kind of spray system do you use?, I can supose that is a wire system and what kind?: Flame wire or Arc spray, this is because with arc spray you must use Ni5Al or Cu10Al and you have in both cases a very good bond strenght quite the same (about 60 MPa), it dipend of the application do you need, Cu10Al is used as bond coat in babbitt bearing coatings, now, if you are speaking about a flame wire system, then, you must use Ni20Al, this because the flame temperature is lower than arc spray temp., and aluminum must have with nichel an esotermical reaction and you reach a bond strenght of about 50 MPa, with NiCr, you can reach at least 30 MPa.