This dilatometer can be operated to 2400°C or 2800°C with the appropriate graphite furnace; optical pyrometers are applied for temperature measurement and control. In this mode, high-temperature resistance samples are tested in glass carbon sample holders under inert atmosphere or vacuum.
Operation to 2000°C is also possible using thermocouples for temperature measurement and control.
The pushrod dilatometer is an ideal tool for determining the change in length when a material is subjected to a controlled temperature program. This is because of its wide application possibilities, its excellent reproducibility and its high accuracy.
Graphite materials, high-temperature ceramics and refractory metals are among the application areas for this versatile, modular high-temperature dilatometer. Developing these materials requires the exact knowledge of the thermal expansion behaviour and of the reactions and phase transitions which occur in the high temperature ranges. It is essential when choosing different materials to be used in combination for various applications to know their thermal expansion coefficients, as this is used for the calculation of thermal stress.
The measuring part, with sample holder and graphite tube furnace, is mounted horizontally. And can be used in a protective gas atmosphere up to 2800°C. The sample and furnace chamber can also be separated by an Al2O3 protective tube for measurements in oxidising atmospheres such as air or O2. The temperature limit for this process is 1680°C.
Heating rates of up to 50K/min and short cooling times down to room temperature are possible due to the water-cooled graphite tube furnace.
A comprehensive safety system constantly checks the cooling water flow, the quality of vacuum and the flow of protective gas during the measurement. The power supply to the furnace is immediately cut off should trouble arise.
The mechanics of the pushrod and the inductive transducer are not influenced by the furnace and sample holder. They remain at a constant temperature due to the thermostatic control of the measuring part. The pushrod applies a load as low as 20cN to the sample.
A software package optimally adapted to the needs of the users is delivered with the DIL 402 E series instrument. This software has easy to understand menus and automated routines, meaning an extremely user-friendly package which also allows for complicated analyses.