Abstract
Silicon-nitride bonded SiC sidelining materials are today the state of the art in modern prebake aluminium cells. SINTEF started in early1990's procedures for performing relevant test methods and quality evaluations of the different commercial materials available on the market. The test methods developed include both chemical and physical properties. Since then a high number of materials have been evaluated and tested on regular basis. New tests and analysis have been included in the test program to investigate and to understand the degradation mechanism in more detail. Lately we have trials with using computed tomography (CT) as a tool to investigate microstructures, pores and cracks inside the materials. A special test method for chemical resistance is developed and used to measure the degradation in the same chemical conditions as in industrial cells. In this special test cell some materials have also been tested in oxygen atmosphere to investigate the degradation of ceramic materials, for instance with using inert anode technology. In the paper overall test results will be shown and examples on good and bad quality materials will be given.