Ultra-precise thermal expansion measurements of ceramic and steel gauge blocks with an interferometric dilatometer

Linear thermal expansion coefficients (LTECs) of two kinds of ceramic gauge block (seven in all) and steel gauge blocks (four in all) were measured in the range -10°C to 60°C with an optical heterodyne interferometric dilatometer. The dilatometer has an uncertainty and reproducibility of the order of 1 × 10 -9 K -1 in LTEC measurements. LTECs of (9.229 ± 0.011) × 10 -6 K -1 were obtained for four 2% Al 2 O 3 partially stabilized zirconia (PSZ) gauge blocks; (9.381 ± 0.003) × 10 -6 K -1 for three 99.9% PSZ gauge blocks; and (10.702 ± 0.064) × 10 -6 K -1 for four steel gauge blocks. These results are discussed in relation to the compositions and production batches of the gauge blocks.