Superconductor Purification Device
When synthesizing ceramic powders for use in high temperature superconductors often the bulk fraction of the synthesized powder that is actually superconductive is low. In the specific case of YBaCuO 1-2-3 synthesis, the oxygen content of the sintered material is delicate (often destroyed by moisture) and critical to the observation of superconductivity above 77K (N2 boiling point). An apparatus is proposed that will preferentially filter out superconductive particles from non-superconductive particles from a finely ground powder (~100 um). Filtered, superconductive material will then be sintered together (or drawn into a copper/brass carrying wire as is common with BSCCO) to yield a ceramic with higher bulk fraction superconductivity (and thus higher current carrying capacity, etc.)
Full description
In the following description, I will describe the synthesis of the common YBCO 123 ceramic superconductor, but the apparatus proposed will work with any granular superconductive media that requires filtering.
In YBCO synthesis, commonly one begins by calcining appropriate stoichiometric ratios of Yttrium oxide, barium carbonate and copper oxide. This process removes excess carbon from the bulk (in CO2). Subsequently the powder is reground into fine powder and annealed/sintered in flowing oxygen to obtain a crystal with the proper oxygen content. Often this regrind/oxygen annealing process is repeated many times until the powder has a high enough bulk density of the superconductive crystalline phase to make the property visible (either by 4 point probe test or observable Meissner effect). Many other process exist to “seed” growth of crystals using a starter crystal, or to go as far as liquefying the YBCO powder to grow larger single crystals (often inside dense, nonreactive BaZr crucibles).
The device that is proposed is a continuous powder separation apparatus that could separate out the pure superconductive particles out of the reground powder (after calcination and oxygen annealing). The pure separated particles would then be pelletized and sintered to make a pure single phase polycrystalline bulk.
A rotational vibrating feed system (as is common in feeder systems in industry) is proposed that will pull powders up and around an internal screw where along that path, magnets are placed to push any superconductive particles into a collection container (as superconductive materials are very strongly diamagnetic). (see figure) The whole apparatus would be cryogenically cooled, to allow superconductivity to be visible in the powder. The continuous circulation of this method means that a device could be left for hours or days for continuous filtration.
This apparatus would allow inexpensive superconductors to be fabricated with loose tolerances/purities on starter chemicals and firing apparatus. The solid state design and ease of integration into conventional vibration machines (could plug directly into a common laboratory vibratory screener) and continuous filtration makes the design robust and efficient.
As stated in the previous section, this apparatus would allow inexpensive superconductors to be fabricated with loose tolerances/purities on starter chemicals and firing apparatus. Superconductive materials have an immense market potential due to their unique properties of zero internal resistance, perfect diamagnetism and other macroscopic manifestations of the materials’ electron quantum coherence.
Full description
In the following description, I will describe the synthesis of the common YBCO 123 ceramic superconductor, but the apparatus proposed will work with any granular superconductive media that requires filtering.
In YBCO synthesis, commonly one begins by calcining appropriate stoichiometric ratios of Yttrium oxide, barium carbonate and copper oxide. This process removes excess carbon from the bulk (in CO2). Subsequently the powder is reground into fine powder and annealed/sintered in flowing oxygen to obtain a crystal with the proper oxygen content. Often this regrind/oxygen annealing process is repeated many times until the powder has a high enough bulk density of the superconductive crystalline phase to make the property visible (either by 4 point probe test or observable Meissner effect). Many other process exist to “seed” growth of crystals using a starter crystal, or to go as far as liquefying the YBCO powder to grow larger single crystals (often inside dense, nonreactive BaZr crucibles).
The device that is proposed is a continuous powder separation apparatus that could separate out the pure superconductive particles out of the reground powder (after calcination and oxygen annealing). The pure separated particles would then be pelletized and sintered to make a pure single phase polycrystalline bulk.
A rotational vibrating feed system (as is common in feeder systems in industry) is proposed that will pull powders up and around an internal screw where along that path, magnets are placed to push any superconductive particles into a collection container (as superconductive materials are very strongly diamagnetic). (see figure) The whole apparatus would be cryogenically cooled, to allow superconductivity to be visible in the powder. The continuous circulation of this method means that a device could be left for hours or days for continuous filtration.
This apparatus would allow inexpensive superconductors to be fabricated with loose tolerances/purities on starter chemicals and firing apparatus. The solid state design and ease of integration into conventional vibration machines (could plug directly into a common laboratory vibratory screener) and continuous filtration makes the design robust and efficient.
As stated in the previous section, this apparatus would allow inexpensive superconductors to be fabricated with loose tolerances/purities on starter chemicals and firing apparatus. Superconductive materials have an immense market potential due to their unique properties of zero internal resistance, perfect diamagnetism and other macroscopic manifestations of the materials’ electron quantum coherence.
