Coating/Anodizing chamber walls to increase wall temp

I need to coat the inside of a vacuum chamber used for semiconductor manufacturing. The coating should be non-porous and able to stand up to aggressive halide attack.

Our challenge is to find a suitable solution that allows us to raise the inner wall temps to 300-400 °C while maintaining a <150 °C chamber temperature for seal survivability. The inside environment is a vacuum 1mT to 10Torr and must remain ultra-clean. Is a thick hard anodize possible for this? What about putting another type of coating over the hard anodize? Please advise.

Thank you.

This is just a stab in the dark because we don't have any information on the design of the apparatus. Titanium or a titanium alloy might be able to withstand this kind of abuse, but we find that stainless vacuum vessels which are coated with various nitrides and oxynitrides can withstand short-term halogen exposure. Repeated thermal cycles of this magnitude are going to be tough on ceramic coatings, though. A rhenium or gold plating is possible, but the interlayer for these coatings would have to be suitable for use with halogens (e.g., a nickel strike is not suitable).