| Abstract: | Materials for the nitric acid industry Particularly demanding requirements are imposed on components exposed to nitric acid. Where metallic materials are concerned, attention must be paid not only to general corrosion, but also to intergranular and selective attack in many cases. A distinction is made between three sectors for which different materials are employed: - a Subazeotropic and azeotropic nitric acids not contaminated with oxidants,
- b Subazeotropic and azeotropic nitric acids containing oxidants, such as chromates, and
- c Superazeotropic, primarily highly-concentrated nitric acids.
The advantages and disadvantages of the materials used in the three sectors, namely austenitic chromium-nickel-(molybdenum) steels, high-silicon austenitic chromium-nickel steels, iron-silicon casting materials, glass-lined steel, glass, aluminum (alloys), titanium, zirconium, tantalum-niobium alloys, tantalum and platinum, are illustrated. Special features to be considered in corrosion tests on steel grades resistant to nitric acid are also described. |
