Thermal Shock Test of Synthetic Diamond Crystals

摘要

Thermal stability is one of most important properties to consider for synthetic diamond crystals. The metal impurities included in the matrix will expand faster than the diamond because of its low thermal expansion. This increases its internal stresses. If this stress is of sufficient magnitude, the diamond may fracture in spite of its great mechanical strength. Our paper describes a special carbon furnace made for the thermal pulse test of synthetic diamond crystals (single particle test). We can select the thermal pulse: ramp rates, hold temperature and hold time. The graphite components are two supporting electrodes held firmly in water-cooled terminals and a pyrolitic - coated furnace (cup shape) which is held between the support electrodes. The temperature is raised (max. 2000°C) because of the heating effect of the contact resistance between the cup-furnace and electrodes.