The bonding between binder coke and filler particles in carbon and graphite electrodes
This study is concerned primarily with electrode carbons used in the aluminium industry. Since they are two-phase carbon composites, the quality of the interfaces between the filler and the mixture of small filler particles and pitch constituting the binder phase significantly affects their properties. In order to promote the use of coal-derived products for this application, the present study aims to gain a better understanding of the factors influencing the quality of binder/filler properties in electrode carbons and the effect of interface quality on important electrode properties. Interfaces between the binder phase and filler particles in electrode carbons can be classified under SEM examination of etched surfaces, and the interface quality can be assessed by point counting. This quality affects both the strength and the electrical resistivity. The two main types of poor quality interface are caused by fissures resulting from the relaxation of moulding stress or shrinkage associated with pitch carbonisation and by voids formed on volatile release from the pitch. Pitch content is the most critical parameter, but even at optimum pitch levels, variation between fillers causes differences in quality. The strength of commercial electrode carbons depends on pore structure parameters but the values ascribed to coefficients in the relationships vary with the nature of the filler used.
Bibliographic Reference: EUR 13993 EN (1992) 83 pp., MF, ECU 4, blow-up copy ECU 13.50
Record Number: 199210550 / Last updated on: 1994-12-02
Original language: en
Available languages: en