Gas pycnometer: precise measurement of the density of solid and porous materials
Determine the actual density of your materials using the gas pycnometer
The gas pycnometer is a density measurement technique that uses an inert gas, usually helium or nitrogen, to analyze solid, porous, or powdery materials. It determines the true density of a sample by taking into account the volume occupied by the material, excluding open pores and interstitials.
Recognized for its precision and reproducibility, this method is commonly used in the pharmaceutical, food, materials, polymer and ceramic industries, where characterization of the physical properties of materials is essential.
How does the gas pycnometer work?
The gas pycnometer is based on the principle of gas expansion in a measuring cell. The process takes place in several stages:
- Sample introduction – The solid or powdered sample is placed in a sealed measuring chamber.
- Reference gas injection – An inert gas is introduced into an adjacent chamber of known volume.
- Pressure balancing – A valve opens to allow gas to distribute between the reference chamber and the chamber containing the sample.
- Pressure change measurement – The final pressure is recorded, and using the ideal gas law, the actual volume of the sample is calculated.
- Calculating Density – Since the mass of the sample is known, the actual density is determined by the relationship density = mass/volume.
This method allows the density of solids to be measured without being influenced by the open porosity of the material, which differentiates it from conventional methods of measuring apparent density.
Technical characteristics of the gas pycnometer
The gas pycnometer offers unmatched accuracy for determining the true density of solids and powders. Its main features are:
- Type of gas used : helium (most common due to its small molecular size) or nitrogen.
- Measurement accuracy : typically less than 0.01% relative error.
- Analysis chamber volume : suitable for samples of varying sizes (from a few mm³ to several cm³).
- Analysis time : fast, with measurements taken in minutes.
- Material compatibility : Applicable to non-volatile and chemically stable materials in the measuring atmosphere.
- Applicable standards : ASTM D2856, ISO 12154, and other material characterization standards.
Thanks to these performances, the gas pycnometer is an essential tool for quality control and research analyses.
For which matrices is the gas pycnometer suitable?
The gas pycnometer is designed for the analysis of various solid matrices, whether dense, porous or powdered:
Main industrial applications of gas pycnometer
The gas pycnometer is used in many industrial sectors to characterize the physical properties of materials:
Léa Géréec
Technical and scientific advisor
