high conductivity fluid.

I am looking for a non-toxic, non-inflammable low cost (disposable) fluid, with a thermal conductivity as good as, or better than water - I can't find much else but olive oil (0.2 w/mK) as opposed to water at

The application is inside an argon purged chamber, with a graphite furnace in the middle. I suspect water vapour is attacking the element from our current system.

Any suggestions would be greatly appreciated as usual.

Thanks

Steve Taylor