Yep those are what I was thinking of; thanks for the cover, internet friend!

Also now I recall we were looking at pressure vessels made of Hastelloy; that was stupid expensive but they had corrosion-resistant properties that were very attractive for that application. And then management bought them and told us to deploy them for a process that was basically a low-temp filtration process. wtf, ok sure, the material is compatible but Hastellonis way overkill. Whatever, it’s your money to burn but damn.