Development of Gallium and Gallium-Based Small-Size Eutectic Melting Fixed Points for Calibration Procedures on Autonomous Platforms

Melting/freezing temperature 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 in order to design small-size fixed-point devices for metrological monitoring of temperature sensors on autonomous (e.g., space borne) platforms. The results show that Ga and some Ga-based eutectic alloys in small cells can be used as melting fixed points. The repeatability of melting temperatures of Ga, Ga–In, Ga–Sn, and Ga–Zn fixed points is studied. The effects of the concentration of the second element of Ga-based eutectic alloys and the thermal history on the melting plateau’s shape and the melting temperature are studied.