Creep Deformation of Carbon-Based Cathode Materials for Low-Temperature Aluminum Electrolysis

Abstract

The uniaxial-compression creep behavior of semi-graphitic carbon products was investigated using modified Rapoport equipment in a K₃AlF₆–Na₃AlF₆–AlF₃ and a Na₃AlF₆–AlF₃ system. The stress exponent is low for the K₃AlF₆–Na₃AlF₆–AlF₃ system in the steady-state creep stage. With an increase in graphitization degree and grain size, the interlayer space and porosity of the tested samples decrease after aluminum electrolysis. A low temperature can suppress carbon-cathode damage. Based on these stress exponents and a microstructural investigation using transmission electron microscopy, it is proposed that dislocation glide is the dominant creep mechanism for the carbon cathode during aluminum electrolysis in the steady-state creep stage.