Chemical and electrochemical dissolution of chromium at room and elevated temperatures

Abstract

The influence of temperature on electrochemical and chemical dissolution of chromium was studied in the acidic sulphuric solutions. The hydrogen evolution reaction, as well as the anodic dissolution and chemical dissolution of chromium from activated surfaces in sulphuric acid solutions pH 1 follow the Arrhenius law, with the apparent activation energies of 35 kJ mol-1, 58 kJ mol-1 and 62 kJ mol-1, respectively. The higher activation energy of the chemical dissolution of chromium leads to the signifycantly noticeable chemical corrosion on elevated temperatures in comparison with the electrochemical corrosion.

Ispitivan je uticaj temperature na elektrohemijsko i hemijsko rastvaranje hroma u kiselim rastvorima sulfata. Reakcije izdvajanja vodonika, anodnog rastvaranja i hemijskog rastvaranja hroma sa aktivirane površine hroma u rastvoru sumporne kiseline pH 1 slede Arenijusovu zavisnost sa prividnom energijom aktivacije 35 kJ mol-1, 58 kJ mol-1 i 62 kJ mol-1, respektivno. Velika energija aktivacije hemijskog rastvaranja hroma dovodi na povišenim temperaturama do znatno izraženije hemijske korozije u odnosu na elektrohemijsku koroziju.