Abstract
This paper describes the components and composition of smut produced on iron and steel by pickling with sulfuric acid, which is the most popular agent for pickling.
The experiments were conducted by X-ray diffractiometry and differential thermal analysis.
The following results were obtained:
1) The principal component of the smut produced by pickling with sulfuric acid was confirmed to be cementite Fe3C by X-ray diffractiometry and differential thermal analysis.
2) The other components confirmed were sulfides and oxides of copper and nickel, oxides and phosphatides of iron, and sulfides of manganese. Accordingly, its composition was rather complicated.
3) Compounds of cobalt and chromium were not confirmed. However, the presence of traces of these compounds would be probable.
