32 results about "Self field" patented technology

The invention discloses a superconducting stack brazing method and a mold for high-temperature superconducting current leads. The superconducting strips to be welded and the brazing welding strips are alternately put into a mold cavity made of a metal material with good thermal conductivity. The mold core and counterweight are pressed on the superconducting tape. Under vacuum conditions, the mold is heated to the brazing temperature and kept for 10-15 minutes, and then the mold is rapidly cooled to the solidification point of the brazing material to complete the welding. The critical current of the high-temperature superconducting tape with low thermal conductivity is only 100-120A under the self-field of 77K, which is much smaller than the operating current of thousands to tens of thousands of amperes of large superconducting magnets. The superconducting tapes must be welded and stacked for use. The price of the bismuth-based superconducting tape using Ag-5.3wt.% Au alloy as the matrix is ​​5-6 times that of the ordinary bismuth-based superconducting tape; and the price of the superconducting stack of foreign high-temperature superconducting companies is almost doubled. The method of the invention welds the superconducting stack with the mold, which can ensure that the current-carrying performance will not be degraded, the longitudinal heat leakage will not be increased, the welding between the superconducting strips is even, and the performance requirement of low interlayer resistance can be met.

The invention discloses a vacuum welding device and a method for a high-temperature superconducting stack used for a large-sized magnet current lead. The vacuum welding device comprises an independent heating vacuum chamber, a cold base and a hot base, wherein the cold base and the hot base are arranged in the vacuum chamber. The interior of the vacuum chamber also comprises a movable welding die and a moving part which can be used for enabling the die to move in the vacuum chamber. After the welding die is contacted with the hot base through the moving part and heated to specified temperature, the welding die is separated from the hot base and is contacted with the cold base to realize rapid cooling. According to the vacuum welding device and the welding method, the superconducting stack is high in density, welding effect and current-carrying capability; and 7-stacked critical current measured under self-fields at 77K can reach 70 percent of the critical current of an original strip, and 4-stacked critical current exceeds the 80 percent critical current of the original strip. The superconducting stack can be applied to the large-sized magnet current lead as a discharge current conductor, and therefore, the effect of reducing heat emission and heat transfer of the lead is achieved, the cooling power is saved, and the operating environment of a magnet is improved.