The Apparatus for Thermomechanical Analysis of Clay-based Ceramics

Abstract

The apparatus for dynamical thermomechanical analysis (D-TMA) measuring the resonant frequency of the flexural vibration and internal damping of the sample using the impulse excitation technique (IET) is described. Since the measurement is conducted at temperatures up to 1250 °C, electromagnetic impulser is used for excitation. The free vibrations are registered by the electret microphone, stored, and then turned into a frequency spectrum using the fast Fourier transformation where the resonant frequency can be found. The furnace is built from refractory porous alumina bricks and alumina fiber pads. The heating elements are four SiC rods connected to a temperature controller. The temperature is measured with Pt-PtRh10 thermocouple in the close vicinity of the sample.