When working with aggressive chemicals, the use of greases is often highly restricted (or prohibited) and we are often asked what we use. In working with liquid oxidisers (nitrogen tetroxide, nitric acid and hydrogen fluoride), we have generally found that the greases based on ‘FOMBLIN’™ fluids have served us very well, and in particular, we have made extensive use of Rocol’s™ RT15 grade (www.rocol.com.). Fomblin is a fluorocarbon fluid originally produced by the Ausimont company (subsequently taken over by Solvay) and, acting as consultants for the European Space Agency, we did extensive testing of some of their fluids and were very impressed with them. The greases based on the Fomblin fluids are made (in very simple terms) by mixing them with extremely fine particles of PTFE, so as well as being chemically inert, they are “not bad” lubricants. Of course, these materials are relatively expensive, but the consequences of using an inadequate material tend to be far more costly!
Having brought RT15 in to the lab for chemical applications, it has subsequently proved “very popular” for many other uses, not least of which are some of the more demanding requirements for automotive applications!