The results of the space technological experiments performed with the suprconducting and magnetic alloys

On board the orbital complex “Salyut-6-Soyuz” during long-term near 0-gravity space flight the technological experiments on synthesis of the superconducting MoGa₅, MO₃Ga and Nb₃Sn intermetallic compounds by means of liquid-phase diffusion and on bulk crystallization of the hypoeutectic superconducting Pb-Sn alloy and magnetically ordered Gd₃Co and (Gd_0.2Tb_0.8)₃Co compounds have been performed. During the process of the liquid-phase diffusion considerable changes of the formation of the reaction layers (mechanisms, phase composition, thickness, etc.) in the superconducting Mo-Ga and Nb-Sn systems were observed. MoGa₅, Nb₆Sn₅ and NbSn₂ phases were found in the ground-based samples while in the flight samples the formation of MoGa₅, Mo₃Ga, Nb₃Sn and Nb₆Sn₅ phases was observed. As a result of the changes of the phase composition of the diffusion layers in the flight samples two superconducting transitions at 18.3 and 5.7 K were established (only one transition at 6.9K was measured for the ground-based sample) (Savitsky et al., Izv. Akad. Nauk SSSR, Metals5, 224–232, 1982; Zemskov et al., Izv. Akad. Nauk SSSR, Physics49, 673–680, 1985). Considerable increasing of the critical current measured for the Pb-Sn flight sample has been observed (Savitsky et al., Dokl. Akad. Nauk SSSR257, 102–104, 1981; Zemskov et al., 1985). Better homogeneity and crystal structure perfection of the flight Gd₃Co and (Gd_0.2Tb_0.8)₃Co samples have been established by means of the micro-zonde and low-temperature X-ray technique (Savitsky et al., Acta Astronautica11, 691–696, 1984; Zemskov et al., 1985). Different behaviour of the ground-based and flight samples in the process of magnetization and the displacements of the temperatures of the magnetic phase transitions have been observed.