pVT-Untersuchung
| System | GNOMIX pVT |
|---|---|
| Description | The Gnomix pVT Apparatus generates pressure-specific volume-temperature measurements using high-pressure dilatometry. pVT data are equation-of-state thermodynamic properties that describe the compressibility and volumetric expansion of the material. Dilatometry measures the change in volume of a specimen subjected to different temperatures and pressures. The GNOMIX PVT (Pressure Volume Temperature) Apparatus was the first commercially available instrument for fundamental and applied studies of the thermodynamic behaviour of a wide range of materials at high pressures to 200 MPa and temperatures to more than 400°C. During an experimental run the specific volume (or density) of a material is measured as a function of temperature and pressure. The technique is based on the use of a confining fluid (mercury) and a nickel sample cup, together guaranteeing a true pressure in the sample at all times, even if it melts or solidifies. |
| Technical Data | - Specific Volume of materials is a function of pressure and temperature as Isobaric respective Isothermic - Pressure range: 10 to 200 MPa - Temperature range: 20° to 400°C in steps of 10 K - The sample (1-2 g) is enclosed in a Piezometer cell - One end of the cell is attached to flexible metal bellows - The cell is occupied by a confining fluid under vacuum e.g. Mercury - Hydrostatic pressure of Silicon Oil is produced in the pressure vessel surrounding the cell - The length change of the bellows is measured by a Linear Variable Differential Transducer (LVDT) |
| Results | - pVT curves - bulk modulus - volumetric expansion coefficient - compressibility |