The Optical Dilatometer measurement technique is included in the ELS-MDF instrument.
○ Is based on two optics which are framing both the ends of the sample that is free to expand in both directions
○ Allows to extend the range of research to temperatures higher than the softening point
○ Works in the range between 25°C and 1600°C
The applications of optical dilatometry include:
- Measurement of thermal expansion. ELS-MDF can be used also to measure the thermal expansion of ultra-thin materials and soften ones;
- Sintering studies;
- Optimization of the firing cycle of ceramic bodies;
- Quality control of raw materials.
Thermal expansion and coefficient of thermal expansion (CTE) curves of materials:
Thermal expansion curve of a LAS glass-ceramic (used for cooktops). This material shows negative CTE till 850°C (high thermal shock resistance), then glass transition at about 880°C, dilatometric softening (970°C) and eucriptite-spondumene phase transition.
Study of the behaviour of advanced ceramics very thin samples during an industrial process:
Low Temperature Cofired Ceramics (LTCC) are thin tapes (in our case, 100 microns thick) obtained by tape casting. During the co-firing process, the binder burnout takes place. As the temperature increases, the glass phase present forms a viscous melt at low temperatures (below 900°C), that activates liquid phase sintering.
Optimization of ceramic bodies composition when the firing cycle is established:
Small changes in formulations correspond to a great variability in firing behaviour. The body with 15% dolomite shows a high tolerance towards accidental variations in technological parameters, whereas the other two bodies are extremely sensitive to even the smallest variations in firing conditions.