DIL L75 VS CRYO – Copper – Thermal expansion
Copper sample – Thermal expansion / ultra low temperature
Thermal analysis does not only mean high temperature measurements but also includes experiments at very low temperatures. There are many fields where low or even ultra-low temperature measurements are interesting. For example for satellites and space travel, the temperatures the used materials have to withstand are below 10 K (- 260°C).
Of course, thermal expansion, phase changes and reactivity in that range have to be known. For thermal expansion, the Linseis L 75 dilatometer series can be equipped with a closed loop helium cryostat to enable measurements in the range of 10 K.
In this example, a copper standard was measured by a Linseis L 75 cryo dilatometer from 10 K to 400 K. (-260°C to 125 °C). Therefore the sample was put into the system, the sample chamber was evacuated and then the sample was cooled down to 10 K with controlled cooling rate, followed by the given expansion measurement during controlled heating with 5 K/min. As the curve shows, there is a zone of non-linear expansion between -260°C and 200°C, followed by linear expansion from -200°C to 125°C. The CTE at the ultra low temperature is also found to be slightly different.