CORROSION OF ALLOYS IN AQUEOUS HYDROFLUORIC-NITRIC ACID SOLUTIONS

Materials for the construction of dissolvers, columns. evaporators, and piping were evaluated in boiling mixtures of hydrofluoric-nitric acids for three 48-hr periods. Included in the tests were Carpenter-20. Hastelloy F. Incoloy 804. Monel, tantalum, types 309, and 316 extra-lowcarbon-content stainless steel The data indicated that none of the materials tested was suitable on a long-term basis for process equipment at the acid concentrations studied. (auth)