Electrometallurgical Processes during the Formation of a Superconducting Coating on Cryogyroscope Rotors.

The present study is focused on the formation of a superconducting niobium coating on cryogyroscope rotors. The application of a superconducting coating onto a cryogyroscope rotor can significantly improve the orientation accuracy of a moving object in space. Electrometallurgical processes, necessary to form a superconducting niobium coating on a cryogyroscope rotor, are considered. An electrochemical unit for applying electrolytic coatings onto spherical substrates was developed. An original cathode design for obtaining smooth continuous niobium coatings on spherical samples is proposed. Niobium coatings were electrodeposited on carbositall rotors in NaCl–KCl–NaF(10 wt%)–K₂NbF₇(8 wt%)–Nb melt at 750°C using galvanostatic electrolysis. The conditions for the electrodeposition of niobium coatings were selected. A unit for the electrochemical polishing of niobium was developed. The parameters of electrochemical polishing for niobium coatings on spherical samples in H₂SO₄:HF (9:1) electrolyte were identified. A protective insulating layer of niobium pentaoxide was applied to Nb-coated rotors by anodizing in 1% orthophosphoric acid solution. The modes of the potentiostatic electrolysis for anodizing spherical samples were established. [ABSTRACT FROM AUTHOR]