dilatometrit

Dilatometry is a technique used to measure the change in size of a material as a function of temperature or time. A dilatometer is the instrument used to perform this measurement. It typically consists of a sample holder, a heating or cooling system, and a displacement sensor. The displacement sensor, often a linear variable differential transformer (LVDT) or a mechanical lever system, accurately records any expansion or contraction of the sample. The heating or cooling is usually controlled by a furnace or a cryostat, allowing for precise temperature profiling.

The primary application of dilatometry is to determine the coefficient of thermal expansion (CTE) of a material. This property is crucial in engineering design, especially for applications where materials are subjected to temperature fluctuations. By measuring the dimensional change over a known temperature range, the CTE can be calculated. Dilatometry can also be used to study phase transitions, such as melting, glass transitions, and crystallizations, as these events often involve significant volume changes. Other applications include quality control of materials, research into material behavior under thermal stress, and the characterization of ceramics, metals, polymers, and composites. Different types of dilatometers exist, including push-rod, optical, and interferometric dilatometers, each suited for specific sample types and measurement requirements.