Standard measures of thermal expansion made of monocrystalline aluminum oxide for a broad range of temperatures

Standard measures of linear thermal expansion made of monocrystalline alumi num oxide have been developed. The measures have a 59 degrees orientation r elative to the trigonal axis of the crystalline lattice. The raw material f or making the measures is obtained by the Stepanov's method of growing shap ed monocrystalline semifinished products with a highly accurate crystallogr aphic orientation from a melt. The parameters of the measures are optimized for testing high-temperature relative dilatometers with transducers made o f polycrystalline corundum. The coefficient of linear expansion of the new measures was checked in the range 90-1800 K and exact values of the coeffic ient were obtained for a board range of temperatures.