In this e-Book you will learn more about the grades of stainless steel and nickel alloys that have adequate corrosion resistance to warrant consideration of their use in sulphuric acid service.
The content is intended to serve as a guide to metals that may be suitable for duty in the acid but consultation and testing are recommended to support a decision on the material of construction.
The corrosion characteristics of H2SO4 are not straight forward and need to be understood in order to make material selection choices.
The corrosion of metals is an electrochemical process during which the metal is dissolved at the anode whilst the balancing reaction at the cathode may be one of a number depending on the nature of the chemical.
In a reducing acid the cathodic reaction is usually the reduction of hydrogen ions resulting in the formation of hydrogen gas.
Hydrochloric acid, HCl is an example of a reducing acid. On the other hand in oxidising acids the cathodic reactions may vary. As an example, in nitric acid, HNO3,
it may be HNO3 + 3H+ + 3e- = NO + 2H2OO