New DIL 803/803L Two Sample Dilatometer By TA Instruments


To maximize sample throughput, the DIL 803/803L offers two-sample simultaneous operation in a horizontal dilatometer. The DIL803/803L can also be operated with an inert reference sample for differential measurement, reducing the influence of measurement system expansion and increasing measurement accuracy under dynamic temperature conditions. The DIL 803 is designed for measurements under vacuum or inert gas while the DIL 803L is designed for measurements under air, making the DIL 803L ideally suited to measuring ceramic materials.

Measurement Principle

The horizontal furnace configuration guarantees optimal temperature uniformity and precludes air currents associated with convection. High sensitivity displacement measurements are made using a high resolution LVDT, guaranteeing that even the smallest thermal expansion events are measured made easily and accurately. The measuring head of the DIL803/803L is thermally stabilized and insensitive to shocks.

The DIL 803/803L increases sample throughput by enabling the measurement of two samples simultaneously. Alternatively, the DIL 803/803L may operate as a differential dilatometer, in which one of the sample positions is replaced by an inert reference material. This technique improves absolute measurement accuracy by incorporating a standard for use as a system expansion correction.

Measurement Example

An example of the two sample measurement benefit is shown in the data to the right. In this example, the thermal expansion of the glaze on a ceramic body is measured. This glaze is a thin film and is not freestanding, and so must be measured while applied to the ceramic body. In order to remove the influence of the ceramic substrate from the measurement, the unglazed ceramic was measured at the same time as the glazed part. The thermal expansion due to the unglazed ceramic was subtracted from the total measurement, leaving a quantitative measurement of the glaze dimension change.

Temperature Range

Furnaces are available that meet the specialized demands of temperature and heating rate from -160 to 2400°C. These furnaces can be easily exchanged and multiple furnaces can be used with a single instrument. Accurate temperature measurements are made through the selection of the appropriate thermocouple or pyrometer type for the temperature range of interest. The thermocouple is placed in close proximity and at a representative position to ensure accurate temperature measurement. In all cases, appropriate care is taken to avoid metal contact which may lead to alloying and solid state diffusion.

Measuring Systems

Inert measuring systems are available in a variety of materials. These sample tubes, bearings, and pushrods are easily interchanged to meet the needs of the measurement at hand. In order to prevent system interaction with the sample, these measuring systems are available in fused silica, Al2O3, sapphire, graphite and tungsten. Certified reference materials are also available for calibration and verification of instrument performance.

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