Electrochemical Comparative Characteristics of La(Fe,Si)13 Type Materials with Different Content of Co in Acidified Phosphate Environment in Presence of Cl- Ions

Abstract

In the paper the electrochemical characteristics of alloys based on La(Fe,Si)₁₃ phase have been presented. The material for research was the LaFe_11.8-xCo_xSi_1.2 alloy with different cobalt content. Presented electrochemical characteristics provide information about pitting corrosion. This kind of corrosion is one of the most common local corrosion, it is especially undesirable for multi-phase alloys based on rare earth elements, as it contributes to the sudden and unexpected destruction of the surface of the material in working conditions. In the paper the results of potentiokinetic corrosion tests determined for LaFe_10.72Co_1.08Si_1.2 and LaFe_11.00Co_0.8Si_1.2 alloys in acidified phosphate solution (pH = 3) with different addition of chloride ions (Cl^-) have been presented. Also analysis of alloys surface before and after corrosion measurement have been presented. The surface analysis have been carried out on the basis of profilometric roughness tests and optical microscopy observation. The studies have shown low resistance of LaFe_10.72Co_1.08Si_1.2 and LaFe_11.00Co_0.8Si_1.2 alloys to pitting corrosion, which, however, increases with Co content increase.

DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19536