At&tad--A
technique for determining the thermal shock resistance ofhighly inhomogeneous industrial carbon materials has been developed. The technique is based on the controlled imposition of internal transient temperature gradients in a disk-shaped test specimen by conducting a constant direct current through the central area of the disk. The geometrical disk data, the power produced in the disk. the time-dependent radial surface temperature, and the time period needed to build up the necessary stress to crack the test specimen are used to calculate the individual thermal shock resistance of each specimen. The technique therefore gives the thermal shock resistance for one single test specimen as an absolute quantity, rather than a threshold value of energy input or temperature drop needed to crack the specimen. as given by other methods. Test measurements were performed on anthracitebased materials specially designed to show the validity of the technique, as well as on a commercial prebaked anode for aluminium production. The thermal shock resistance measured using this new method agrees qualitatively well with thermal shock resistance calculated from other material parameters.