Reference Material Development for Round Robin Test of Thermal Expansion

A thermal expansion reference material was developed for a round robin test to raise national competition and measurement ability and reliability of experimental data. A gadolinia-zirconia (Gd2O3-ZrO2) composite was chosen for reference material, which has high temperature stability. 20 mol%(or 42.38 wt%) of gadolinia was added to zirconia to have no structure change within measurement temperature range. An optimal mixing and milling condition was set up to obtain uniform mixture of main and sub materials. And density and grain size were measured to investigate sinterability of material. From EPMA and XRD, it was found that the component isotopes distributed uniformly. Under argon gas environment, several thermal expansion tests were performed from room temperature to 1500 .deg. C. The measurement results obtained distributes similarly and uncertainty and model formula were also evaluated. It is expected that the gadolinia-zirconia reference material would be applied to maintenance of measurement instrument and calibration. Furthermore, from the round robin test of thermal expansion, deviation indication between laboratories and cause of deviation will be noticed and reliability of measurement and measurement ability will be increased, too