Dilatometers

TA Instruments unique True Differential configuration makes our dilatometers the preferred choice for the high accuracy measurement of coefficient of thermal expansion (CTE). The high precision linear position sensor, the thermostatted measuring head housing and the use of thermally ultra-stable materials all contribute to the  outstanding displacement resolution, and ensure the most accurate measurement of low CTE values.

DIL 820 Series dilatometers operate in a vertical orientation, making it uniquely set up for the analysis of sintering, studies in Rate Controlled Sintering (RCS) mode and the determination of dilatometric parameters of samples otherwise difficult to be analysed on classic dilatometers with horizontal design. The 820 Series dilatometers are also particularly well suited for powder samples and samples that during the test develop a vitreous phase. That would lead the sample to interact with the sample holder hence generate friction. A major source of errors in the measurement of dilatometric parameters.

All four units  feature the new optical encoder with 1nm resolution. That when combined with the True Differential of the DIL822, the result is simply the best possible sensitivity and CTE accuracy on the market.

The vertical orientation also prevents the measuring systems and furnace tubes from sagging when used over long test periods at high temperatures, resulting in extended operational life.

Equipped with a  linear motor generating a constant load  throughout the experiment, in the 820 Series the pushrod is kept in contact with the sample regardless of dimensional changes.

Quenching dilatometers allow to study the heat treatment of steel and metal alloys, helping identifying the heating rate, the quenching rate and the isothermal dwell times to be used in metals manufacturing to yield the crystalline structure to necessary to meet the required physical properties.

The related microstructural changes may be observed through process simulation with real-time monitoring of dimensional change. Among other things, measurements of distinct alloy compositions are used to create time-temperature transformation diagrams (TTT) and continuous-cooling transformation diagrams (CCT), which are critical in process design and optimization. With heating rates up to 4000°C/sec and cooling rates of 2500°C/sec, the DIL 805 series quenching dilatometers provide the most accurate measurements over the widest range of heating, cooling and deformation conditions, allowing for the most sophisticated characterization and optimization of metals.

Optical dilatometry is an innovative and versatile technique capable to measure, without any contact with the sample, dimensional changes in the submicro range and beyond softening point into the melt, hence reproducing real industrial firing cycle conditions.

The contact-less measuring principle of optical dilatometers greatly simplifies sample preparation process because reduces the need of a very precise parallelism between the two ends of the specimen, and the shape of the sample is not as critical as in pushrod dilatometry because the software automatically aligns the optical paths of sample extremities.