Influence of temperature and humidity on the strength of low temperature co-fired ceramics

Strength degradation in glass and ceramic materials is related to subcritical crack growth mechanisms acting at the crack tip during mechanical loading. In this work the effect of humidity and temperature on the strength of a commercial low temperature co-fired ceramic was investigated using a biaxial testing procedure. Experiments were performed in argon and in air at different stress rates between 25 and 125 °C. The effect of humidity on strength was assessed at room temperature varying only the relative humidity. The sole effect of temperature was evaluated in argon at high stress rates. The combined effect of humidity and temperature was determined in air, testing at different temperatures. Results showed the existence of an inert strength of the material at room temperature. Measurements in ambient air showed a counterbalance effect of temperature and humidity yielding an almost constant strength for this material between 25 and 125 °C.