Melting points of gallium and of binary eutectics with gallium realized in small cells

Melting/freezing curves are studied for the single-component Ga and bimetallic eutectic alloys Ga-In, Ga-Sn, Ga-Zn and Ga-Al in small-size cells. These phase-transition studies were conducted at VNIIOFI and SDL in order to design small-size fixed-point devices for metrological monitoring of temperature sensors on autonomous platforms. Our prime objective is to develop technology to improve the long-term performance of in-flight blackbody calibration sources of space-borne radiometers. The repeatability of the melting temperature of Ga and the eutectic melting temperatures of Ga-In, Ga-Sn and Ga-Zn fixed points were studied. Our results show that small cells containing Ga and some Ga-based eutectic alloys can be used as melting fixed-point standards.