Abstract
Recent trends in the chemical industry are in the direction of higher temperatures and pressures. Few-data are available in the literature on corrosion of metals and alloys at temperatures above the atmospheric boiling points of the solutions. This paper presents data on the corrosion of a variety of metals and alloys by nitric, phosphoric, acetic acids and sodium hydroxide at temperatures up to 425 degrees F. The metals and alloys include CF-8, CF-8M, CN-7MCu, CB-30, cast titanium and high silicon iron.
In general, corrosion increases rapidly as the temperature is raised above boiling and in some cases very rapid and previously unexpected attack occurs. Some data at lower temperatures are included for comparison.
Data are also presented on the inhibiting effects of metallic ions in solution and in some cases spectacular decreases in corrosion rates are observed. An example is the effect of copper ion on corrosion of stainless steel by phosphoric acid. Sub-surface corrosion of stainless steel by hot caustic is described. Borderline passivity effects in hot acids are dicussed. Equipment for conducting corrosion tests at elevated temperatures and pressures is described.
