Influence of Cr additions on corrosion resistance of Fe- and Co-based metallic glasses and nanocrystals in H2SO4

The influence of Cr concentration on the corrosion resistance of Fe73.5Si13.5B9Nb3Cu1 and Co73.5Si13.5B9Nb3Cu1 metallic glasses was studied by DC electrochemical methods in different concentrations of H2SO4 (1, 3 and 5 M) at room temperature. Gravimetric tests were performed to establish the reliability of the data obtained electrochemically. Every test was determined with the same material in different states: amorphous, nanocrystalline and crystalline. In all cases metallic glasses and nanocrystals showed better resistance to corrosion in the tested conditions with increasing chromium concentration. However, in test conditions, the Fe-based materials maintained a high corrosion rate. The corrosion resistance of Co-based materials was slightly greater than that of Fe-based materials.