STUDY ON CYCLIC THERMODURABILITY OF CARBON MATERIALS

The thermodurability of glass carbon — one of the most promising carbon materials used in the production of lum inophors and semico nductor 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 m icroflow initiation and progress, the signal re ception of acoustic emission was used. It is shown that a heavy disloc ation 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 whe n heated than on cooling of the sa mple, it implies the damage accumulation in the structure under the thermal - cyclic handling of the glass carbon sa mples. It is found that damage acc u mulation curves reflected by the acoustic emission pulses differ on the s tage of heating and cooling. It is proposed to use a total curve of the acoustic emission pulses as a potent ial destruction sign of a glass - carbon product when heated.