Study on cyclic thermodurability of carbon materials

The thermodurability of glass carbon - one of the most promising carbon materials used in the production of luminophors and semiconductor materials, optical single crystals, etc. - is investigated. The aim of this work was to study the behavior of glass carbon in the course of the thermal-cycle testing. As a diagnostic technique of the microflow initiation and progress, the signal reception of acoustic emission was used. It is shown that a heavy dislocation motion on the thermal-cycle exposure recognized in the acoustic emission signals is observed in the glass-carbon samples when heated. As far as the number of impulses is higher when heated than on cooling of the sample, it implies the damage accumulation in the structure under the thermal-cyclic handling of the glass carbon samples. It is found that damage accumulation curves reflected by the acoustic emission pulses differ on the stage of heating and cooling. It is proposed to use a total curve of the acoustic emission pulses as a potential destruction sign of a glass-carbon product when heated.