Dilatometry

What is dilatometry used for?

Dilatometry is used to measure characteristics including thermal expansion, glass transition temperature, and phase changes. Typical samples include metals, ceramics, polymers, and composites, giving dilatometry applications in the development and quality assurance of semiconductors, plastics, and construction materials, among others. One of the most typical standardized measurements conducted with a dilatometer is the ASTM E228 test for determining linear thermal expansion.

How does dilatometry work?

There are various experimental setups for dilatometry, but fundamentally they all work by applying an external heat source to a sample. As the temperature is increased, the physical changes the samples undergo, such as the volume, length, density, and phase changes, are monitored and recorded.

Push rod dilatometer vs. optical dilatometer

In push-rod dilatometry, the sample is in contact with a rod, which in turn connects to a strain gauge. As the sample is heated and expands, it will apply a force to the rod which is recorded by the gauge, therefore providing data on the physical changes of the sample. This method is straightforward and works well for hard solids like metals and ceramics.

Optical dilatometry uses a non-contact detection method, in which a digital camera captures the microscopic changes in sample dimensions as it is heated. This method is advantageous as it can be used on softer, more ductile materials like polymers, as well as fragile crystals, thin films, and organic matter.

Need thermal analysis services?

Measurlabs offers coefficient of thermal expansion (CTE) measurements and additional thermal analyses using dilatometry as well as several other techniques. Available methods include thermomechanical analysis (TMA), differential scanning calorimetry (DSC), and thermogravimetric analysis.