What materials are resistant to hot chlorine? I'm looking to do an experiment involving hot chlorine gas (900 Celsius), however at the moment the only material I'm aware of that could cope with this is Hastelloy's C-22 alloy. What other alternatives exist?
Short answer — none. Hastelloy C276 or C22 are the best alloys, also considering availability, presumably cost is no object. At that high temperature there is no readily available data. At 500 °C for a limited time experiment, other nickel alloys like 625 or 201 and even 316 SS have some limited life. But for 900 °C, I expect the Hastelloy C family was recommended because they have the best life at about 500 °C. Your conditions are where it would be best to get a manufacturer of high alloys or ceramics to work with you.