Patent Application
20250210253
This application is based on and claims the priority benefit of European patent application number 22305437, filed on Apr. 4, 2022, entitled “METHOD FOR MANUFACTURING SUPERCONDUCTING COILS AND DEVICE,” and of European patent application number 22305449, filed on Apr. 4, 2022, entitled “UNIFORM COATING OF A SURFACE,” which are hereby incorporated by reference to the maximum extent allowable by law.
The present disclosure is related to methods or processes and devices for manufacturing superconducting coils. More specifically it is related to methods or devices that involve a multistage coating of a surface of a structure. The structure may be for example a cylinder in its broader definition, that is, a surface in space made of parallel straight lines (generating lines), and the surface may be an inner or an outer surface of the cylinder.
The challenges of the 21st century must be met with technology that pushes the current boundaries of science. Energy generation from fusion power, medical procedures like magnetic resonance imaging machines and transportation system like magnetic levitation trains, among many others, all have in common that they require strong magnetic fields in specific configurations to function properly. Therefore, the world of the future will require methods, devices and mechanisms that can produce strong magnetic fields and that meet the demands of a growing sector.
The latest developments in magnetic fields make use of High-Temperature Superconductors (HTS). HTS are materials that exhibit superconducting properties at temperatures generally above 77 K, the boiling point of nitrogen. HTS materials exhibit a resistance of zero under the superconducting circumstances, which is usually a matter of being at the right temperature. Having zero resistance, currents can flow freely and at high intensity through these superconducting materials. Ultimately this makes it possible to produce magnetic fields of high strength and with specific characteristics as required by the application.
Presently, magnetic devices are constructed with large magnets that are shaped into the form of a coil; magnets may be either permanent or electrical depending on cost or application. In applications where the field needs a special configuration, for instance, in stellarators, the coil must be twisted to a complicated shape during construction. This greatly increases costs during the design phase; stellarator design is very complicated and requires a lot of testing, so constructing many magnets coils requires a lot of time and of money.
A document dealing with the construction of superconducting coils is U.S. Pat. No. 9,812,233 to Sazaki, et. al., which describes the current state of the art concerning the construction of superconducting material films, also described as tapes. The current state of the art considers producing tapes which are stacked to form a cable like structure. This cable like structure is then shaped according to the needs of the application. It may be cut to shape, twisted, stacked or otherwise.
A method for constructing superconducting coils is described in U.S. Pat. No. 8,655,423 to Miyazaki, et al. Miyazaki describes a superconducting coil formed of several layers of different materials. A group of these layers is described as constituting a superconducting coil portion which is formed of thin-film superconducting wires. The coils described by Miyazaki and those that are common in the art are constructed by arranging superconducting films, also called superconducting tapes, into the shape of wires and the wires are then further configured into the shape of coils. According to a review of the prior art, superconducting coils are formed by stacking superconducting films or layers so that electric current may flow in a desired direction and produce the appropriate magnetic field configuration.
To the best knowledge and understanding of the inventors, the prior art doesn't teach any other method by which the superconducting films or tapes may be used to conduct a current.
The tapes themselves can be constructed through several methods described in the art. In U.S. Pat. No. 10,935,799 to Majkic, et al. a method for fabricating high quality superconducting tapes is disclosed. The method of Majkic is limited to applications that require a very thin tape structure. It is not apparent from the description of Majkic how the process may defeat the limitations of, for example, different tape geometries. The method described in this prior art is limited to the rectangular shape of the appropriate size.
An apparatus and method for forming a film on a tape substrate is disclosed in U.S. Pat. No. 6,147,033 to Youm et al. This apparatus further exemplifies the limitations of the current methods in the state of the art. A thin film of superconducting material is deposited on a rolling cylinder, that unwinds a tape substrate, thus forming the tape. This method does not allow for a different shape than that of a rectangular tape. Further, if the tape is left for an inordinate amount on tape on the rolling cylinder, the whole tape could be damaged.
Superconducting tapes themselves are also in short supply, as their demand is high. There is also the problem of the size and shape of the tapes which can only be constructed a few centimeters wide. In addition, the process that arranges the tapes into wires and further into coils is lengthy and error prone.
Thus, there remains a need for an efficient and less costly alternative to the coils that are used in magnetic applications. Further, there is a need for a method or device that allows for the construction of superconducting coils that can be easily interchanged, so that configuration changes may be realized quickly and at a little cost. The prior art is yet to overcome the limitation of producing superconducting tapes of any shape or size, currently shapes are limited to rectangular geometries.
One embodiment addresses all or some of the drawbacks of known methods and devices for constructing superconducting coils.
One embodiment provides a method for manufacturing a superconducting coil, the method comprising steps of:
In one embodiment, forming the second stacking comprises depositing at least a layer of a superconductive material and a layer of a low-resistivity material on the superconductive material layer; and the method further comprises removing material at least from the superconductive material layer and the low-resistivity material layer, in order to create a pattern that forms a groove at least in said superconductive material and low-resistivity material layers.
In one embodiment, the method further comprises, after the rotating step and before forming the first stacking, a step of electropolishing the structure in a wet chamber, for example using an electrolytic solution and electrodes.
In one embodiment, the wet chamber, the cold chamber and the hot chamber are a single chamber.
In another embodiment, the wet chamber, the cold chamber and the hot chamber are separate chambers.
In one embodiment:
In one embodiment, the temperature in the cold chamber is the room temperature.
In one embodiment, the temperature in the hot chamber is higher than 500° C.
In one embodiment, forming the first stacking comprises at least a physical vapor deposition step, like sputtering, for example magnetron sputtering, inclined substrate deposition, ion beam deposition and/or ion beam assisted deposition.
In one embodiment, forming the first stacking comprises:
In one embodiment, forming the second stacking comprises at least a physical vapor deposition step, for example sputtering or pulsed laser deposition, and/or a chemical vapor deposition step, for example a metal organic chemical vapor deposition step.
In one embodiment, forming the second stacking comprises depositing at least a layer of a superconductive material, for example rare-earth barium copper oxide or yttrium barium copper oxide, using metal-organic chemical vapor deposition, for example using a vaporized precursor at a uniform temperature and laminar flow, or using pulsed laser deposition.
In one embodiment, the superconductive material is a rare-earth barium copper oxide or an yttrium barium copper oxide.
In one embodiment, depositing the layer of the superconductive material uses metal-organic chemical vapor deposition, for example using a vaporized precursor at a uniform temperature and laminar flow, or uses pulsed laser deposition.
In one embodiment, forming the second stacking comprises a step of depositing a layer of a low-resistivity material like silver on the superconductive material layer.
In one embodiment, the low-resistivity material is silver.
In one embodiment, forming the second stacking comprises:
In one embodiment, forming the second stacking comprises:
In one embodiment, the cooling step comprises injecting an inert gas or vapor at a fourth temperature lower than the third temperature.
In one embodiment, the step of depositing the sixth layer, or the layer of the superconductive material, comprises filling in the hot chamber a vaporized superconductive material precursor at a fifth temperature, for example between 250° C. and 280° C.
In one embodiment, the method further comprises heating the structure to a second temperature higher than the first temperature, for example between 800° C. and 900° C., between depositing the fifth layer and depositing the sixth layer, or the layer of the superconductive material.
In one embodiment, the method further comprises repeating the steps of forming the second stacking, in the same or in different order, in order to form at least multiple second stackings on the first stacking, preferably several times, for example between 4 and 80 times.
In one embodiment, the method further comprises, preferably after the step of forming the second stacking or the multiple second stackings:
One embodiment provides a superconducting coil obtained by the method according to an embodiment, the superconducting coil comprising:
In one embodiment, the second stacking comprises a layer of a superconductive material and a layer of a low-resistivity material on the superconductive material layer; and the superconducting coil further comprises a groove at least in said superconductive material and low-resistivity material layers.
In one embodiment:
In one embodiment:
In one embodiment, the stacking comprises multiple second stackings, with the layers of the different second stackings being in the same or in a different order.
In one embodiment, the structure is composed of Hastelloy or covered by an Hastelloy layer.
In one embodiment, the structure is a cylinder.
One embodiment provides a device for manufacturing a superconducting coil comprising a structure, wherein the device is adapted to implement the method according to an embodiment, and comprises:
The foregoing features and advantages, as well as others, will be described in detail in the following description of specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, in which:
Like features have been designated by like references in the various figures. In particular, the structural and/or functional features that are common among the various embodiments may have the same references and may dispose identical structural, dimensional and material properties.
For the sake of clarity, only the operations and elements that are useful for an understanding of the embodiments described herein have been illustrated and described in detail.
Unless indicated otherwise, when reference is made to two elements connected together, this signifies a direct connection without any intermediate elements other than conductors, and when reference is made to two elements coupled together, this signifies that these two elements can be connected or they can be coupled via one or more other elements.
In the following disclosure, unless s indicated otherwise, when reference is made to absolute positional qualifiers, such as the terms “front”, “back”, “top”, “bottom”, “left”, “right”, etc., or to relative positional qualifiers, such as the terms “above”, “below”, “higher”, “lower”, etc., or to qualifiers of orientation, such as “horizontal”, “vertical”, etc., reference is made to the orientation shown in the figures.
Unless specified otherwise, the expressions “around”, “approximately”, “substantially” and “in the order of” signify within 10%, and preferably within 5%.
The figures are not to scale. It should be noted that the drawings refer to an embodiment of the method and device for manufacturing superconducting coils, sometimes referred simply as method or device, respectively, when no ambiguity is anticipated. Other embodiments may be possible, as someone with appropriate training may readily appreciate. The actual dimension and/or shape of each of the components of the embodiment may vary. Only important details of the embodiment are shown, however one of ordinary skill in the art can appreciate how the overall device may be constructed, without undue experimentation. Some details have been omitted from the drawings, but the inventors believe that adding these details is unnecessary for the overall appreciation of the characteristics of the invention disclosed. These omitted details include, among others, elements for holding or fixing the device or its functional components. Some characteristics of the embodiment appear exaggerated to facilitate understanding. The embodiments disclosed, and alternatives observed should not be considered as limiting the invention in any way.
In the drawings, the structure is a right circular cylinder (cylinder 202) and the surface to be coated is an outer surface of said cylinder. In another embodiment, the surface to be coated may be an inner surface of the cylinder. Other shapes of a structure having a surface to be coated are possible. In other embodiments, the surface to be coated could be an inner or an outer surface of a non-circular and/or non-right cylinder, or any other appropriate structure.
When reference is made to a cylinder, this includes a flat-faced ring or a hollow cylinder.
Other examples of a device for coating uniformly a surface, which can be applied for manufacturing a superconducting coil, is given in the European patent application number EP22305449 filed on Apr. 4, 2022 by the same applicant “RENAISSANCE FUSION”, entitled “UNIFORM COATING OF A SURFACE” which is hereby incorporated by reference to the maximum extent allowable by law.
The wet chamber 101 may be filled by an electrolytic solution to perform electropolishing 106 on the surface of the cylinder 202. Therefore, the wet chamber 101 may also include electrodes for this end.
In the cold chamber 103, several processes may occur, based on a physical vapor deposition (PVD) technique. In the illustrated embodiment, there are three processes: two processes are based on sputtering, typically magnetron sputtering, in sputtering of alumina step 108 adapted to deposit alumina and sputtering of yttria step 110 adapted to deposit yttria, and one process is based on ion beam assisted deposition (IBAD), in IBAD MgO step 112 adapted to deposit magnesium oxide (MgO).
Other PVD techniques may be used in the cold chamber, which may depend on the material to deposit. For example:
Therefore, the cold chamber 103 preferably includes at least an ejector, like a target or a nozzle, and/or may include a source, depending on the technique used, for example for magnetron sputtering and IBAD.
When reference is made to an ejector, this may include a target or a nozzle, depending on the technique used.
The hot chamber 105 involves several processes based on a physical vapor deposition (PVD) technique and/or a chemical vapor deposition (CVD) technique. In the illustrated embodiment, at least six processes may be involved, including: the heating of the cylinder 202 to a temperature between 700° C. and 800° C. (first temperature) in the heating to between 700° C. and 800° C. step 120; three CVD and/or PVD steps adapted to deposit materials, the MgO step 118 adapted to deposit (MgO), the LMO step 116 adapted to deposit lanthanum manganite (LMO), and the REBCO step 114 adapted to deposit rare-earth barium copper oxide (REBCO), or another appropriate superconducting material; the cooling of the cylinder 202 to between 450° C. and 600° C. (third temperature), for example between 500° C. and 600° C., in the cooling between 450° C. and 600° C. step 124; and a CVD or a PVD step adapted to deposit a low-resistivity material, which is silver (Ag) in the example, on the surface of the cylinder 202 in the Ag step 122. Instead of silver, it may be another low-resistivity material, for example a material having an electrical resistivity lower than 5.10−8 Ω.m at 20° C., such as gold (Au), magnesium (Mg), or copper (Cu).
At this stage, the cylinder may be heated again in the heating to between 700° C. and 800° C. step 120, for example to repeat, at least once, the process steps in the hot chamber, or the cylinder 202 may be stopped in the stop rotation of cylinder step 126. The method may also comprise a cool to room temperature step 128, before, after or during the stop rotation of cylinder step 126, where the process ends.
Currently, the cooling to between 450° C. and 600° C. step 124 may be envisioned to be done through convective heating, by injecting a gas or vapor that is inert at a lower temperature (fourth temperature), but other ways may also be possible.
Different CVD or PVD techniques may be used in the hot chamber, which may depend on the material to deposit. For example:
When necessary, depending on the technique used in the REBCO step 114, a heating to between 800° C. and 900° C. step 115 (second temperature), for example between 850° C. and 890° C., may be needed between the LMO step 116 and the REBCO step 114, in order to heat the cylinder 202 to a temperature adapted to the REBCO step 114.
The hot chamber 105 preferably includes at least an ejector like a nozzle for the execution of the CVD and/or PVD processes, depending on the technique(s) used.
The temperature ranges in the cold and hot chambers are given in relation with the techniques used and the materials to deposit. The person skilled in the art will know how to adapt them for other techniques and/or other materials.
The processes in the three chambers, wet 101, cold 103 and hot 105 chambers, may be executed in three separate chambers, meaning that the cylinder would have to be taken out of one chamber and placed in the next one, or they could all be executed in a single chamber.
An example of detailed operations is now described, based on the processes illustrated in
The illustrated method starts in the wet chamber 101. In the wet chamber 101, a cylinder 202 like the one from
In the cold chamber 103, at least a magnetron sputtering ejector, like a target or a nozzle, deposits layers of alumina and yttria, and a target of IBAD deposits magnesium oxide MgO. The first step in the cold chamber 103 is the sputtering of alumina step 108. A magnetron sputtering ejector injects aluminum and oxygen into the chamber, depositing alumina on the surface of the cylinder 202. Once alumina has been deposited, the same or another magnetron sputtering ejector injects yttrium and oxygen into the chamber, depositing yttria on the cylinder surface, in the second step called sputtering of yttria step 110. The last step in the cold chamber is the deposition of MgO through the use of ion beam assisted deposition using a target of magnesium and oxygen. This step is called the IBAD MgO step 112. The steps in the cold chamber 103 can be executed at room temperature. Nevertheless, for the next steps in the method, the surface of the cylinder 202 must be heated. The cylinder 202 must then be transferred to a different chamber that may heat its surface or it may also be possible to heat it using the heating resistors 206.
The first step in the hot chamber 105 is the heating of the cylinder between 700° C. and 800° C. in the heating to between 700° C. and 800° C. step 120. At this temperature, metal-organic chemical vapor deposition MOCVD can be used to deposit MgO and LMO on top of the materials deposited on the cold chamber 103. First, MOCVD is used to deposit MgO in the MgO step 118. The hot chamber 105 is filled with a vaporized MgO precursor at an uniform temperature and exhibiting laminar flow around the cylinder 202, thus depositing MgO on its surface. The same process is repeated in the LMO step 116, this time using a lanthanum manganite LMO precursor at an uniform temperature and laminar flow. After LMO is deposited, the temperature in the hot chamber 105 may be increased further to 850° C., for example between 850° C. and 890° C., in the heating to between 800° C. and 900° C. step 115 before the REBCO step 114. As part of the REBCO step 114, a superconducting material like rare-earth barium copper oxide may be filled with a vaporized REBCO precursor exhibiting laminar flow around the cylinder 202. In an embodiment, the temperature of the REBCO precursor would be between 250° C. and 280° C. (fifth temperature). For each of steps MgO step 118, LMO step 116 and REBCO step 114, pulsed laser deposition (PLD), for example, may be used instead of MOCVD. The cylinder 202 is cooled in the next step in the cooling to between 450° C. and 600° C. step 124. At this temperature it is possible to use chemical-vapor deposition or metal-organic chemical vapor deposition to deposit silver on the surface of the cylinder. Silver, or another low-resistivity material, is deposited in the Ag step 122.
Once the silver deposits, it is now possible to heat the cylinder again and repeat the previous steps of the method. It is possible to repeat the following six or seven steps in order: the heating to between 700° C. and 800° C. step 120, the MOCVD MgO step 118, the LMO step 116, in some cases, the heating to between 850° C. and 890° C. step 115, the REBCO step 114, the cooling to between 450° C. and 600° C. step 124, and the (MO) CVD addition of Ag step 122. These steps may be repeated any number of times, with a total of between 4 and 80 repetitions, for example between 20 and 40 repetitions, being considered appropriate for at least this embodiment.
At any step of the method, but preferably after the (MO) CVD addition of Ag step 122, the cylinder 202 may be made to stop by stopping the rods 204, this is the stop rotation of cylinder step 126. Once the cylinder 202 has been stopped, it may be left to cool to room temperature, in the cool to room temperature step 128. Afterwards, the cylinder 202 may be removed from the chamber and it may then be cut or used as per the needs of the application.
An example of superconducting coil 300 constructed by following the diagram from
All the layers formed in the cold chamber may be called “first stacking of layers” or “first stacking”, and all the layers formed in the hot chamber may be called “second stacking of layers” or “second stacking”.
The alumina, yttria, MgO, LMO layers may be called “buffer layers”. The buffer layers may form an appropriate template for the formation of the superconducting layer.
The final sequence of the four layers in the hot chamber 105, that is, second MgO layer 310, LMO layer 312, REBCO layer 314 and silver layer 316, may be deposited repeatedly in the same or different order. These four layers may be deposited repeatedly on top of the layers deposited during the process in the cold chamber 103, for example on the first MgO layer 308, in order to create a layer stack, or wafer, of between 4 and 80, for example between 20 and 40 sequences.
Other appropriate materials, and number of layers, may be used in place of the ones described here.
For example, instead of the MgO layer in the cold chamber, an yttrium stabilized zirconia (YSZ) layer may be formed, using a PVD technique like sputtering, ISD, IBD or IBAD, and instead of the MgO layer in the hot chamber, an epitaxial YSZ layer may be formed, using for example CVD, MOCVD, or a PVD technique like IBAD.
As another example, instead of the described sequence of layers, the following sequence may be formed on the Hastelloy layer 302 preferably in the following order:
Other embodiments may replace REBCO of the REBCO layer 314 with other rare-earth materials that exhibit high-temperature superconductivity, like YBCO.
Other embodiments may replace silver of the silver layer 316 by another low-resistivity material, for example gold, magnesium, or copper.
In one embodiment, the last silver layer, that is, the silver layer of the last sequence of layers in case of repetition of layers 310, 312, 314, 316, may be replaced by a copper layer. Indeed, the silver layer may be particularly adapted as a starting layer for a repetition of layers, but may be of less interest in the last sequence on which no repetition is made, and a copper layer is cheaper, faster to grow using electroplating for example and harder than silver.
After the last low-resistivity material layer is formed, an additional step of removing material at least from the low-resistivity material layer, the superconductive layer, and possibly at least partially in the buffer layers and/or the layer stack, may be provided, in order to create a pattern that forms one or several grooves 410, as illustrated in
The cylinder of the superconducting coil may be machined to have a particular shape, and the superconducting coil may be assembled to another superconducting coil, of a similar or different shape, like several modular coils, to form an assembly. For example, several superconducting coils may be assembled to form a stellarator.
Example embodiments of the invention are summarized here. Other embodiments can also be understood from the entirety of the specification as well as the claims filed herein.
Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these embodiments can be combined and other variants will readily occur to those skilled in the art.
Finally, the practical implementation of the embodiments and variants described herein is within the capabilities of those skilled in the art based on the functional description provided hereinabove.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22305437.0 | Apr 2022 | EP | regional |
| 22305449.5 | Apr 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/058479 | 3/31/2023 | WO |
