Thermal Shock Test Ceramics

As whisker reinforced silicon nitrides can show an improvement in room temperature strength and fracture toughness one would expect that these cmcs will also possess increased thermal shock resistance.

Thermal shock test ceramics. The thermal shock of ceramic materials is influenced by many factors such as strength young s modulus fracture toughness thermal conductivity and thermal expansion coefficient. Thin circular disks are heated up to 1750 k with a tungsten halogen lamp yielding heating rates up to 1200 k s. At present the research of thermal shock resistance on ceramic material is mostly concentrating on the determination of critical temperature differences thermal shock cycles residual strength. This is probably due to the fact that thermal shock failure is a complicated function of the external thermal shock conditions and of the temperature functions of five different material properties.

The thermal shock and thermal fatigue behaviour of ceramic materials has been determined with a new type of testing system 3. Thermal shock testing exposes products to alternating low and high temperatures to accelerate failures caused by temperature cycles or thermal shocks during normal use. The transition between temperature extremes occurs very rapidly greater than 15 c per minute.