Thermal Expansion Measurements on Thoria and Hafnia to 4500°F

Equipment for measuring thermal expansion to 4500°F is described. Linear thermal expansion to 4500°F was measured on thoria and hafnia. Average coefficient of linear expansion from 75° to 4500°F for thoria was 6.05 x 10‐3per O F; for stabilized hafnia with 10 wt% Y 2 O 3 additions it was 6.33 × 10 −6 per OF, and with 15 wt% Y 2 O 3 additions it was 6.27 × 10 −6 per °F.