Cu-niobium alloy exhibits good superconductivity at low temperature and high thermal and electrical conductivity at room temperature, so it has a broad application prospect in particle accelerator and nuclear reactor fields. At present, the main methods for preparing Cu-Nb alloy are vacuum induction smelting and mechanical alloying. However, the vacuum induction smelting method has a slow cooling rate, and copper and niobium are almost insoluble in solid state, and the melting point difference is large, so the copper-niobium alloy prepared by this method has a serious segregation tendency. Although the mechanical alloying method can get the copper - niobium alloy with uniform composition and effectively eliminate composition segregation, the copper - niobium alloy produced by this method has high content of impurity elements.
Technical scheme: The preparation method of a copper-niobium superconducting composite material mentioned in the invention comprises the following steps:
(1) The copper powder and niobium powder were mixed evenly, in which the proportion of copper powder was 75 ~ 85% and that of niobium powder was 15 ~ 25%;
(2) pour the evenly mixed copper-niobium powder into the mold and press it into copper-niobium consumable electrode material on the press;
(3) the pressed copper-niobium consumable electrode material is loaded into the vacuum sintering furnace for sintering to obtain copper-niobium consumable electrode;
(4) The copper-niobium consumable electrode is welded on the auxiliary electrode in the shielding gas and smelted in a vacuum arc furnace to obtain the copper-niobium superconducting composite.
Among them, in step (1), the proportion of copper powder is 80 ~ 85%, the proportion of niobium powder is 15 ~ 20%, the particle size of copper powder and niobium powder is 200 ~ 325 mesh, the roller ball mill is used to mix copper powder and niobium powder for 1 ~ 3 hours.
In step (2), the pressure of the press is 150 ~ 400MPa, and the pressure is maintained for 5 ~ 10min when the electrode material is pressed.
Step (3) The sintering temperature of the electrode rod was 800 ~ 900℃, the holding time was 5 ~ 10h, and the vacuum degree was 1×10-3 ~ 1× 10-4Pa.
In Step (4), the electrode melting voltage in the vacuum arc furnace is 20 ~ 35V, the melting current is 2000 ~ 6000A, the furnace pressure is 0.1 ~ 1.2Pa, and the arc length is 25-30mm.
Benefit effect: compared with the prior art, the invention has the obvious advantages that the prepared copper-niobium superconducting composite material has uniform composition, no component segregation phenomenon and no inclusion generation.
