A calibration method for measuring thermal expansions with a push-rod dilatometer

The calibration method for measuring the linear thermal expansion coefficient (LTEC) with a push-rod dilatometer was examined by considering a simple model. To verify the validity of the calibration method, measurements of LTECs for samples of fused silica (SRM 739) and a sample of a single crystal of silicon were carried out with a push-rod dilatometcr in the temperature range from room temperature to 973 K. Measurements of melting points of pure metals for temperature calibration, measurement of the sensitivity of a displacement measurement device with a laser interferometer and evaluation of the influence of fluctuations in room temperature on the measured displacement results were also carried out. As a result, the calibrated results of the LTEC for the silicon sample corresponded to the reference value for silicon to within a deviation +/- 2 percent over the measurement temperature range and the validity of the analysis for the push-rod dilatometer was confirmed. (Author)