Development of long Nb3Ge tape with Tcabove 20 K

Superconducting Nb3Ge tapes were prepared continuously by chemical vapor deposition. The chlorides NbCl4and GeCl2prepared "in situ" were used. Films were deposited on the stainless steel substrate heated by passing the direct current through it. The content of the Nb3Ge phase in the deposited layer films at constant molar ratio of NbCl4and GeCl2depends mainly on the heating current of the substrate as well as on the flow of the reaction gas mixture. The tapes with critical temperatures above 20 K in undoped atmosphere have been produced. The addition of oxygen into the reaction gas mixture in amount up to 0.027 mole did not lower generally the Tc´s under the 20 K value. The critical current densities of the Nb3Ge layers are from 10⁵to 5.10⁵A/cm²in magnetic field of 3 T.