THERMAL EXPANSION OF PALLADIUM-SILVER ALLOYS AT LOW TEMPERATURES

Interferometric measurements of the thermal expansion of palladium, silver and five alloys of these metals are reported in the temperature range 30 to 270°K. The experimental uncertainties rise from approximately 1% at 270°K to 15% at 30°K. The variation of thermal expansion with concentration is non-linear and the form of the variation is not substantially affected by temperature in the range covered. A degree of correlation has been found with related thermodynamic properties of the alloys, and the need has been established for a rigorous theory of the thermal expansion of binary alloys on an atomic scale.