The principle of dilute sulfuric acid
The corrosion process of carbon steel in sulfuric acid is a typical electrochemical corrosion. The nature, surface state of metal materials, and metal cathode phase impurities, pH, and temperature all affect the metal's hydrogen depolarization corrosion. Commercially obtained sulfuric acid is generally at the following concentrations: 77.67%, 93%, 98%, 99%, 100%. The sulfuric acid with different concentrations has the following prominent characteristics:
At a certain temperature, the corrosion rate of dilute sulfuric acid on carbon steel increases with increasing concentration; after reaching a certain concentration, the corrosion rate decreases sharply with increasing concentration. Another feature of sulfuric acid corrosion is that the sulfuric acid of the same concentration will greatly increase with increasing temperature. In addition to the corrosiveness of sulfuric acid, which is related to concentration and temperature, impurities in the acid also have a great effect on corrosion. In addition, some physical factors such as media flow rate, solid phase particles, scaling, etc. also affect corrosivity.