Measurement of the changes of carbonaceous materials caused by intercalation of sodium deposited from molten salts electrolyte

Intercalation of sodium into the carbon lining of aluminium electrolysis cells is a common cause of its failure. The effect of sodium on model carbon cathode materials was studied in the system with high activity of sodium (molten NaF–NaCl system). Commercially available carbon materials such as semigraphite and electrographite (Kompozitum, Topol’čany, SK) were chosen as model cathodes. The experiments were carried out at a constant cathode current density of 0.7 A cm⁻². A modified Rapoport test was developed and used to study the expansion of the chosen types of carbon materials.