CN102758106A - Low temperature thermal conductor - Google Patents
Low temperature thermal conductor Download PDFInfo
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- CN102758106A CN102758106A CN201210129694XA CN201210129694A CN102758106A CN 102758106 A CN102758106 A CN 102758106A CN 201210129694X A CN201210129694X A CN 201210129694XA CN 201210129694 A CN201210129694 A CN 201210129694A CN 102758106 A CN102758106 A CN 102758106A
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- aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/026—Alloys based on aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F6/00—Superconducting magnets; Superconducting coils
- H01F6/04—Cooling
Abstract
The invention provides a low temperature thermal conductor. A thermal conductor material having excellent heat transfer properties by obtaining high thermal conductivity even at low temperature of, for example, a liquid nitrogen temperature (77 K) or lower is to provide. A thermal conductor to be used at low temperature of 77 K or lower in the magnetic field of a magnetic flux density of 1 T or more, includes aluminum which has a purity of 99.999% by mass or more and also has the content of iron of 1 ppm by mass or less.
Description
Technical field
The present invention relates to a kind of thermal conductor, said thermal conductor is at the for example low temperature below the 77K, and especially the cryogenic temperature below 20K shows excellent thermal conductivity; And relate more specifically to even when in the high-intensity magnetic field more than the 1T for example, using, also can show the thermal conductor of excellent thermal conductivity.
Background technology
Superconducting magnet has been used to multiple field, for example diagnostic MRI (nuclear magnetic resonance), is used to analyze the NMR (nucleus magnetic resonance) or the magnetic suspension train of purposes.Be cooled to liquid helium helium boiling point 4.2K (Kelvin) the low-temperature superconducting coil and be used as superconducting magnet with the high temperature superconductor coil that refrigerator is cooled to about 20K and used.
Need to use the low temperature below liquid nitrogen boiling point (77K), especially the cryogenic temperature below 20K shows the thermal conductor of high heat conductance, so that these superconducting coils are cooled off effectively and equably.
JP 2007-063671A discloses the aluminium of deepfreeze as the thermal conductor that when low temperature, demonstrates high heat conductance.
JP 2004-283580A discloses a kind of structure of magnetic resonance component; And described can use have 99.999 quality % above (be expressed as sometimes hereinafter " 5N " (five nine) and; In the mass percent symbol of expression purity; Sometimes with symbolic formulation be placed on for " N " successive " 9 " from the beginning number after, for example, the above purity of 99.9999 quality % is expressed as " 6N " (six nine) sometimes); Under cryogenic temperature, can show high thermal conductivity matter, or have the thermal conductor (hot bus-bar) of aluminium conduct between refrigerator and freezing container of above (4N) purity of 99.99 quality %.
Except that aluminium, the known thermal conductor that uses copper in addition, as oxygen free copper with (4N) purity more than the 99.99 quality %.
Yet; These also have such problem at the material that low temperature has high thermal conductivity matter: near superconducting coil (superconducting magnet); Be under the high-intensity magnetic field more than the 1T in the magnetic field that is produced by superconducting coil for example, thermal conductivity reduces, thereby and can not obtain high thermal conductivity matter.
This problem is caused by magneto-resistance effect.Known this effect is that wherein resistivity depends on the external magnetic field and the phenomenon that changes.
Well-known copper shows significant magneto-resistance effect, and the resistivity that increases under the low temperature along with magnetic field significantly increases.As everyone knows, though less than copper, aluminium also shows magneto-resistance effect, and in magnetic field, causes the remarkable increase of resistivity at low temperature.
In the many metals that comprise copper, aluminium and their alloy, resistivity has confidential relation with thermal conductivity, and thermal conductivity reduces when resistivity increases (specific conductivity reduction).
Therefore, there is such problem: along with the evaporation efficiency of the heat conduction property deterioration superconducting coil of the thermal conductor that in high-intensity magnetic field, uses reduces.
Summary of the invention
Therefore; A target of the present invention provides a kind of thermal conductor with outstanding heat conduction property; Said thermal conductor even the low temperature below for example liquid nitrogen temperature (77K) especially obtain high heat conductance in the high-intensity magnetic field of the magnetic flux density of the cryogenic temperature below the 20K more than 1T.
The inventor has been found that through control of purity also is controlled in mass below the 1ppm, even aluminium (Al) also can suppress magneto-resistance effect significantly more than 99.999 quality % and with iron level.The thermal conductor of being processed by this aluminium has high heat conductance, even and when when freezing temp is for example used in the high-intensity magnetic field of the magnetic flux density more than 1T below the 77K, also show excellent heat conduction property.
Aspect in 2, the invention provides according to aspect 1 described thermal conductor, wherein said aluminium has the above purity of 99.9999 quality %.
Aspect 3, the present invention provides according to aspect 1 described thermal conductor, wherein said aluminium has the above purity of 99.99998 quality %.
Aspect 5, the present invention is provided for cooling off the thermal conductor of superconducting magnet, said thermal conductor uses according to each the described thermal conductor in the aspect 1 to 4.
According to the present invention; A kind of thermal conductor with outstanding heat conduction property can be provided; Said thermal conductor even the low temperature below for example liquid nitrogen temperature (77K) especially also have high heat conductance in the high-intensity magnetic field of the magnetic flux density of the cryogenic temperature below the 20K more than 1T.
Description of drawings
Fig. 1 be show the specific conductivity index and the magnetic field (magnetic flux density) that applied between the figure of relation.
Fig. 2 be show thermal conductivity and the magnetic field (magnetic flux density) that applied between the figure of relation.
Fig. 3 is the temperature difference and the figure of the relation between magnetic field (magnetic flux density) that shows the two ends of sheet sample.
Embodiment
Thermal conductor according to the present invention comprises and has the purity more than the 99.999 quality % and have the aluminium of the iron level of 1ppm in mass, so as in addition the magnetic field of magnetic flux density more than the 1T in use.
At first; The inventor finds to have the above purity of 99.999 quality % and have the aluminium of the iron level of 1ppm in mass, even when using in the magnetic field of the magnetic flux density more than 1T; Can not show magneto-resistance effect significantly yet, and thereby suppress the reduction of thermal conductivity.Thereby accomplished the present invention.
Like disclosed content in for example JP 2009-242865A and JP 2009-242866A; Known to cryogenic temperature liquid helium temperature for example, resistivity reduces along with the increase of aluminium purity such as 5N (purity that 99.999 quality % are above) and 6N (purity more than the 99.9999 quality %).
Like disclosed content in JP 2010-106329A for example, has the above purity of 99.999 quality % and has in mass that the aluminium of the iron level below the 1ppm also is known.
Though known when when not applying the state in magnetic field through purity being increased to about 4N; Can improve the specific conductivity of aluminium at cryogenic temperature; But when in the magnetic field of the above magnetic flux density of 1T, using, significant magneto-resistance effect can occur, thereby and cause the reduction of specific conductivity.Consider with the aluminium of 4N purity similarly, the raffinal of 5N and 6N purity can not obtain high conductivity in high-intensity magnetic field.
Therefore, according to thinking that the aluminium that has the above purity of 99.999 quality % and have a following iron level of 1ppm in mass can not be used in the thermal conductor that uses in the magnetic field of the also magnetic flux density more than 1T.
The inventor has been found that at first as stated, and the increase (being the decline of thermal conductivity) that it has been generally acknowledged that resistivity in high-intensity magnetic field can not occur in the above grade of 5N and raffinal that have the iron level below the 1ppm in mass.
Though will in following embodiment, describe in detail, as the copper of thermal conductor,, find also in the high-purity copper of 6N or more high-grade purity that its thermal conductivity sharply descends in high-intensity magnetic field, though this material is used as thermal conductor usually even at 5N about usually.Therefore, the inventor finds that through obtaining high purity even in high-intensity magnetic field, also keeping the phenomenon of highly conc be that aluminium institute is peculiar.
As stated, in thermal conductor according to the present invention, the amount that contains iron in the aluminium is controlled in mass below the 1ppm.
To describe in detail as following, according to thinking that it the reasons are as follows: can guarantee that as the amount of the iron of ferromagnetic element compacting suppresses magneto-resistance effect through control, thereby and make it possible to guarantee to suppress the decline of the thermal conductivity that causes by the high-intensity magnetic field that is applied.
Below 77K (196 ℃), the more preferably temperature below the 20K (253 ℃) and applying when using in the state in magnetic field of the magnetic flux density more than the 1T, show effect significantly according to thermal conductor of the present invention.
Before thermal conductor according to the present invention is elaborated, the thermal conductor that why uses the material with excellent electric conductivity is had high heat conductance describe.
In the many metals that comprise copper, aluminium and their alloy, the migration of unbound electron is the main mechanism of conduction, and can improve specific conductivity through unbound electron is moved more easily.On the other hand, unbound electron helps the thermal conductivity of these metals significantly, and when unbound electron moves more easily, can obtain high heat conductance.
Known Wiedemann-Franz (WF) law is the thermal conductivity of plain metal and the mutual relationship between the specific conductivity.Also the thermal conductivity below about 40K of known raffinal can be confirmed by the following equality (1) as the more accurate relational expression of high pure metal; And the thermal conductivity below about 40K of high-purity copper can confirm that (two equalities are all quoted the KOGAKU from TEION by following equality (2); 39 volumes (2004); The 1st phase, the 25-32 page or leaf).
κ＝1/(1.83×10
-7×T
2+1.09/RRR/T) (1)
κ＝1/(6.41×10
-8×T
2.4+0.685/RRR/T) (2)
Wherein
κ: thermal conductivity (W/m/K)
T: temperature (K)
RRR: Residual Resistivity Ratio
Residual Resistivity Ratio RRR is represented by following equality (3)
RRR＝ρ
297K/ρ
T (3)
Wherein
ρ
297K: in the resistivity (n Ω cm) of the temperature of 297K
ρ
T: in the resistivity (n Ω cm) of temperature T (K)
Among this paper, the ρ of known copper
297Kρ with aluminium
297KThe influence in the magnetic field that receives purity hardly and apply from the outside, and almost be constant (for example, the ρ of aluminium
297KBe about 2,700, and the ρ of copper
297KBe about 1,500).
Therefore, as conspicuous to (3) from equality (1), the thermal conductivity that improves (along with resistivity reduces) copper and aluminium along with specific conductivity increases.
Details according to thermal conductor of the present invention will be described below.
(1) level of impurity
As stated, thermal conductor according to the present invention is characterised in that to comprise and has the purity more than the 99.999 quality % and have the aluminium of the following iron level of 1ppm in mass.Owing to following reason, purity is more than the preferred 99.9999 quality %, more preferably 99.99998 quality % above (hereinafter is expressed as " 6N8 " sometimes).In other words, purity is high more, and the reduction of specific conductivity is few more in the high-intensity magnetic field.In addition, under the situation of the purity more than the 99.9999 quality %, compare with the situation that does not apply magnetic field, resistivity possibly descend sometimes in the high-intensity magnetic field more than 1T.
The content of iron is preferably in mass below the 0.1ppm.
Reason is in high-intensity magnetic field, to suppress the reduction of specific conductivity more definitely.
Still have many unclear places through iron level being controlled to the machine-processed aspect that can suppress the specific conductivity minimizing in mass below the 1ppm.Yet, think that at present the mechanism inferred is as follows.That is, because be ferromagnetic element, iron receives the influence of high-intensity magnetic field probably, therefore, when iron when surpassing that the content of 1ppm exists in mass, the influence that puts on the specific conductivity increases, and therefore the specific conductivity under high-intensity magnetic field possibly reduce.When the content of iron is 0.1ppm, almost can fully get rid of influence owing to ferromagnetic substance.Yet the mechanism of these suppositions does not limit the scope of the invention.
Known Ni and Co are the ferromagnetic elements outside the deironing.Yet because for highly purified aluminium, these elements are removed with currently known methods easily, and the numerical value of its content is not problem.Yet the content of these Ni and Co also is below the preferred 1ppm, and more preferably below the 0.1ppm.
The purity of aluminium can define with certain methods.For example, it can be confirmed through the content of MEASUREMENT OF Al.Yet, preferably confirm the purity of aluminium in the following manner: the content (quality %) of the following 33 kinds of elements that contain as impurity in the MEASUREMENT OF Al and from 100% deduct these content summation so that confirm the purity of aluminium with high precision with simple relatively method.
In this article, 33 kinds of elements that contain as impurity are lithium (Li), beryllium (Be), boron (B), sodium (Na), magnesium (Mg), silicon (Si), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), arsenic (As), zirconium (Zr), molybdenum (Mo), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), barium (Ba), lanthanum (La), cerium (Ce), platinum (Pt), mercury (Hg), plumbous (Pb) and bismuth (Bi).
The content of these elements can be through for example glow discharge mass spectrometry assay.
(2) method of purification
This raffinal can obtain through using any purification (making with extra care) method.Illustrate acquisition some methods of purification below according to raffinal of the present invention.Yet method of purification is not limited to these methods certainly.
Three layers of electrolytic process
Can use three layers of electrolytic process as a kind of method that obtains raffinal; Wherein add commercially available aluminium with relative low-purity (for example having given level 1) in the Al-Cu alloy layer like 99.9% specified among JIS-H2102 purity and under molten state as anode; And the electrolyzer wherein contain ALUMNIUM FLUORIDE and barium fluoride is set, thereby and on negative electrode, produce raffinal above that.
In said three layers of electrolytic process, the aluminium that mainly can obtain to have the above purity of 99.999 quality %.Can with comparalive ease the iron level in the aluminium be suppressed at below the 1 quality ppm.
The unidirectional solidification method
For example, can use the unidirectional solidification method so that further improve the purity of the raffinal that obtains by three layers of electrolytic process.
The content separately of Fe content and Ti, V, Cr and Zr can optionally reduce through the unidirectional solidification method.
Known unidirectional solidification method is such method: for example; Wherein use body of heater mobile model tube furnace that aluminium is melted in boiler tube; And the end unidirectional solidification through body of heater is extracted out from boiler tube afterwards; And the content of Ti, V, Cr and each element of Zr optionally increases in a side of solidifying initiating terminal, and the content of Fe is accomplished end one side (solidifying the opposition side of initiating terminal) and optionally increased solidifying.Therefore, accomplish the end both sides with solidifying, can reduce Fe definitely through the initiating terminal that solidifies of excision gained ingot blank, and the content of Ti, V, Cr and each element of Zr.Can be through confirming the specific part of the ingot blank that obtains by the unidirectional solidification method that must excision at the content of suitable interval analytical element along solidifying direction, so that only keep Fe, and the part that reduces fully of the total content of Ti, V, Cr and Zr content.
Order for implementing through three layers of electrolytic process are purified and purified through the unidirectional solidification method has no particular limits.Usually, purify through three layers of electrolytic process, and purify through the unidirectional solidification method afterwards.For example, can alternately and times without number carry out any one in perhaps can purifying times without number or both through the purification of three layers of electrolytic process with through the purification of unidirectional solidification method.Particularly preferably be through the unidirectional solidification method and purify times without number.
In this method, can obtain to have the aluminium of the purity more than the 99.9999 quality % through the combination of using three layers of electrolytic process and unidirectional solidification method.Can also the content of iron in the aluminium be suppressed in mass below the 1ppm with easier mode, and more preferably in mass below the 0.1ppm.
Zone melting process
In addition, zone melting process can be used so that obtain to have highly purified aluminium, for example the above purity of 99.99998 quality %.When using zone melting process aptly, can more confirm ground the iron level in the aluminium is suppressed in mass below the 1ppm, and more preferably in mass below the 0.1ppm.
Especially, effectively use aluminium method of purification (being described in the method among the japanese patent application No. 2010-064544) through the zone melting process of inventing by the inventor.
When removing the impurity in the aluminium,, preferably place therein on the surface of boat of aluminium and be pre-formed alumina layer, and zone melting purification is also 3 * 10 in order to prevent diffusion of contaminants to the aluminium that heated through the zone melting purification method
-5Carry out in the vacuum below the Pa, and more preferably from 3 * 10
-6Pa to 2 * 10
-5Pa separates impurity so that guarantee from molten aluminum.
Preferably carry out pre-treatment, wherein will pass through the raw-material upper layer dissolving of aluminium of zone melting purification before the zone melting purification in advance and remove carrying out.Pretreatment process is had no particular limits, and can use the multiple processing of in correlative technology field, using, so that remove the raw-material upper layer of aluminium.
Pretreated instance comprises s.t., electropolishing processing etc.
The above-mentioned boat that in the zone melting purification method, uses is graphite boat preferably, and preferably after above-mentioned alumina layer forms, in rare gas element or vacuum, cures.
In the process of zone melting purification, based on the raw-material sectional dimension w of aluminium
Al, preferably with the width adjusting of aluminium melt zone of fusing to w
AlMore than * 1.5 and w
AlBelow * 6.
The aluminium starting material that in purification, use use three layers of electrolytic process and unidirectional solidification method to obtain through combination, for example, and the preferred raffinal that uses with the above purity of 99.9999 quality %.
In zone melting process, for example, through moving the radio-frequency coil that is used for ratio-frequency heating melt zone is moved from an end of raw material aluminium to the other end, thereby and can carry out zone melting purification whole raw material aluminium.In the component of impurity metallic elements; Peritectoid component (Ti, V, Cr, As, Se, Zr and Mo) tends to be enriched to the fusion initial section; And eutectic composition (from above-mentioned 33 kinds of impurity elements, remove 7 kinds of elements of peritectoid after 26 kinds of remaining elements) is tended to be enriched to fusion and is accomplished section, thereby and the zone after removing the raw-material two ends of aluminium can obtain raffinal.
Melt zone is being moved predetermined distance, after the raw-material distance that passes through on vertically of aluminium, accomplishing ratio-frequency heating and also this melt zone is solidified.After solidifying, cut off the high purity aluminum material of aluminium (for example, two ends being cut) to obtain to purify.
When a plurality of aluminium starting material are vertically arranged (at the travel direction of melt zone); Preferably make these aluminium starting material vertically contact with each other and vertically handle as aluminium starting material; Melt zone from an end (promptly then; In the raw-material end of a plurality of aluminium, longitudinally do not have in raw-material two ends of adjacent aluminium) move to the other end (that is, in the raw-material end of a plurality of aluminium, longitudinally do not exist in raw-material two ends of adjacent aluminium another).
Reason is raw-material terminal connection of aluminium that in the zone melting process, contacts with each other, thereby and can obtain long aluminum.
As stated, afterwards, can repeat once more from the zone melting of an end to the other end from the zone melting (zone melting purification) of the raw-material end to end of aluminium.The number of multiplicity (number of passage) is normally more than 1 and below 20.Even the number of passage exceeds above scope, the raising of refining effect is limited.
In order to remove 7 kinds of elements of peritectoid effectively, the number of passage is preferably more than 3 times, and more preferably more than 5 times.When the number of passage was lower than above-mentioned scope, 7 kinds of elements of peritectoid were not easy to move, thereby and can not obtain enough refining effects.
The reasons are as follows.When a plurality of aluminium starting material are vertically being contacted with each other when arranging; When the number of passage is less than 3 times; The shape (especially height dimension) of the aluminium of purifying after connecting becomes inhomogeneous, and therefore in purification process the fusion width change sometimes, and be not easy to obtain uniform purification.
(3) forming method
The ingot blank of the raffinal that will be obtained by above-mentioned method of purification uses several different methods to be configured as required shape.
Forming method is as follows.Yet forming method is not limited thereto.
Rolling
When the thermal conductor that is obtained was plate or line, rolling was a kind of effective forming method.
Rolling can use ordinary method to carry out, and for example, wherein makes it pass the method for pair of rolls through the space of when exerting pressure, ingot blank being inserted between these rollers.Under the situation of rolling, have no particular limits for concrete technology and condition (temperature of material and roller, number of processes, shrinking percentage etc.), and can suitably set these concrete technology and conditions, condition is not damage effect of the present invention.
For having no particular limits through the final sheet material that obtains of rolling and the size of wire rod.As for preferred sizes, under the situation of sheet material, thickness is 0.1mm to 3mm, and under the situation of wire rod, diameter is 0.1mm to 3mm.
When thickness during,, possibly be not easy sometimes to obtain as the required enough transport properties of thermal conductor because xsect reduces less than 0.1mm.On the contrary, when thickness during, be difficult to sometimes utilize snappiness and be out of shape greater than 3mm.When thickness is 0.1mm to 3mm, there is the advantage that for example is prone to processing, and can this material be arranged on the side that utilizes flexible curve container.
Certainly, the shape that obtains through rolling be not limited to sheet material or line and, for example tubulose and H-shape can be through the rolling acquisitions.
Rolling can be hot rolling or warm-rolling, wherein ingot blank heated in advance, and carries out rolling being set in the state that is higher than room temperature afterwards, and perhaps can be wherein that ingot blank is pre-heated not cold rolling.Alternatively, can be with hot rolling or warm-rolling and cold rolling combination use.
Under the situation of rolling, can material be cast in advance or cut into required shape.Under the situation of casting, can adopt ordinary method, but be not limited to such method: for example, wherein raffinal heated also fusion with the formation molten metal, and the raffinal molten metal that is obtained is passed through cooled and solidified in mould.And, under the situation of casting, have no particular limits for condition etc.Heating temperature is generally 700 to 800 ℃, and heating and fusion are carried out in crucible such as plumbago crucible under vacuum or rare gas element (nitrogen, argon gas etc.) atmosphere usually.
The forming method that is different from rolling
Can carry out wire drawing or extrude as the forming method that is different from rolling.For by stretching or extruding the not restriction of shape of acquisition.For example, stretch or extrude the wire rod that is suitable for obtaining to have rounded section.
Stretch to obtain rolling line (rolling wire rod) can obtain through rolling before required linear, and this rolling line that stretches afterwards.
The cross section of the wire rod that is obtained is not limited to circle, and this wire rod can have non-circular xsect, for example ellipse or square-section.
Except that stretching or extruding, required shape also can obtain through the cutting ingot blank.
(4) annealing
In addition, can be randomly to carrying out anneal such as the profiled part of the present invention that rolling obtains by above-mentioned forming method.Can remove usually the strain that under the situation of the cut-out of the material that forms by ingot blank or moulding, produces through carrying out anneal.
Condition to anneal has no particular limits, and is preferred 400 to 600 ℃ of methods that kept one or more hours.
When temperature is lower than 400 ℃, because the strain (dislocation) that comprises in the following reason ingot blank can not reduce fully.Because the factor that increases resistivity is served as in strain (dislocation), excellent transport properties can not show sometimes.When thermal treatment temp was higher than 600 ℃, the solution of the solution of impurity, especially iron entered in the matrix in the solid.Because solid solution matter iron has the considerable influence that strengthens resistivity, transport properties is deterioration sometimes.
More preferably, owing to following reason keeps temperature one or more hours at 430 to 550 ℃.
When temperature is within above-mentioned scope, can strain be eliminated fully, and the iron conduct is with the intermetallic compound existence of aluminium and entering in the matrix as soluble solids.
Can also the following reason of illustration.
As the intermetallic compound of iron and aluminium, for example, known many types are like Al
6Fe, Al
3Fe and Al
mFe (m ≈ 4.5).According to thinking that TR (430 to 550 ℃) in the major part (for example, in volume ratio, more than 50%, preferred more than 70%) of intermetallic compound of the iron that exists in the raffinal material of acquisition after the annealing and aluminium is Al
3Fe.
This Al
3Fe has such advantage: even under situation about existing as throw out, it also can apply adverse influence to specific conductivity hardly.
Can confirm and measurement Al through following method
3The existence of Fe and volume ratio thereof: dissolve matrix (base mateiral) through using chemical solvents, and collect, the residue that operational analysis electron microscope (analyzing TEM) observation is afterwards collected through filtration, and further analysis through filtration.
Can only be made up of above-mentioned raffinal with the above purity of 99.999 quality % according to thermal conductor of the present invention, and also can contain the part that is different from raffinal, for example, protective coating is so that give multiple function.
Though the concrete purposes as according to thermal conductor of the present invention is for example understood the thermal conductor that is used to cool off superconducting magnet; To the not restriction of concrete purposes; And thermal conductor according to the present invention can be used as the multi-purpose thermal conductor that uses at low temperature (below the 77K) (more than 1T) in high-intensity magnetic field and uses, and for example is used for the thermal conductor at NMR cooling testing sample.
Embodiment
Provide in detail as following; Prepared the embodiment 1 (purity that 99.999 quality % are above; 5N-Al), the embodiment 2 (purity that 99.9999 quality % are above; 6N-Al) (purity that 99.99998 quality % are above is 6N8-Al) as the embodiment sample, and measured resistivity (than resistivity) afterwards with embodiment 3.
Comparative example 1 (4N-Al) and the comparative example 2 (3N-Al) with aluminium of 3N grade purity with aluminium of 4N grade purity provide as comparative example below.Through calculating the resistivity of confirming comparative example 1 and 2.
For with copper relatively, the copper sample that preparation has 5N grade purity, and afterwards with comparative example 3 identical ground measured resistivity.
As for copper, use data in literature as comparative example.Comparative example 4 is the copper samples with 4N grade purity, and comparative example 5 is the copper samples with 5N grade purity, and comparative example 6 is the copper samples with 6N grade purity.
(1) preparation of raffinal
At first, it is as follows to be used for preparing the method for embodiment 1 to 3 employed raffinal.
The aluminium of commercially available purity with 99.92 quality % is purified through three layers of electrolytic process, be the raffinal below the 1ppm in mass to obtain to have above purity of 99.999 quality % and iron level.
Specifically, (99.92 quality %) is dosed in the Al-Cu alloy layer with commercially available aluminium, and the composition of electrolyzer is adjusted to 41%AlF
3-35%BaF2-14%CaF
2-10%NaF.760 ℃ of power supplies, and collect the raffinal that is deposited on cathode side.
Through the content of every kind of element in glow discharge spectrometry (using by THERMO ELECTRON Co. " VG9000 " that Ltd makes) this raffinal of analysis, to obtain the result shown in the table 1.
To purify through unidirectional solidification through the raffinal that above-mentioned three layers of electrolytic process obtain, be the raffinal below the 1ppm in mass to obtain to have above purity of 99.9999 quality % and iron level.
Particularly; The raffinal of the 2kg that will obtain through three layers of electrolytic process is placed in the crucible (interior dimensions: 65mm wide * 400mm length * 35mm height); And this crucible is placed in the boiler tube of tube furnace of body of heater mobile model (by the quartz manufacturing, 100mm internal diameter * 1,000mm is long).Through 1 * 10
-2In the vacuum atmosphere of Pa body of heater (crucible) is controlled to 700 ℃ with the raffinal fusion, and with 30mm/ hour speed body of heater is extracted out from boiler tube afterwards and made the raffinal unidirectional solidification.With along its length from solidifying initiating terminal 50mm after cut out from the position of solidifying initiating terminal 150mm, obtain to be measured as 65mm wide * block raffinal that 100mm length * 30mm is thick.
With the content of identical as stated method, to obtain the result shown in the table 1 through each element in this raffinal of glow discharge spectrometry analysis.
Embodiment 3
The purity and the iron level that obtain to have more than the 99.99998 quality % through following zone melting process are the raffinal below the 0.1ppm.
To cut into quadrangular or the similar shape that is measured as about 18mm * 18mm * 100mm from the 6N aluminium ingot that obtains through above-mentioned unidirectional solidification method, and further through with after the 20% aqueous hydrochloric acid acid etching of pure water dilution preparation 3 hours, acquisition aluminium starting material.
Use this aluminium starting material, carry out zone melting process through following method.
Graphite boat is placed in the Vakuumkammer (being measured as external diameter 50mm, internal diameter 46mm, length 1, the silica tube of 400mm) of zone melting purification device.Will serial (purity: 99.99%) be applied to graphite boat and place said raw-material part, suppress simultaneously to form alumina layer by the high-purity alpha-alumina powders A KP that Sumitomo Chemical Co makes.
This graphite boat is cured through ratio-frequency heating under vacuum.
Through 10
-5To 10
-7High frequency heating coil (the heater coil writhing number: 3 circles that is used for zone melting in the vacuum of Pa; Internal diameter 70mm; The frequency of about 100kHz) heating is cured, and boat is moved to the other end with 100mm/ hour speed from an end, thereby one after the other heats whole graphite boat.
Above-mentioned 9 aluminium starting material of the about 780g of gross weight are arranged in to be arranged at place raw-material part in the graphite boat and (be measured as 20mm * 20mm * 1,000mm).Arrange the aluminium starting material of forming by 9 starting material (the raw-material sectional dimension w=18mm of aluminium, length L=900mm, i.e. L=W * 50) with the quadrangular form.
Be sealed in indoor after, vacuumize through turbomolecular pump and squalid rotary pump, reach 1 * 10 up to pressure
-5Below.Afterwards, use high frequency heating coil (radio-frequency coil) heating and fusion to form melt zone at the end of aluminium starting material on vertically.
Regulate output (frequency: 100kHz, the maximum output: of high frequency electric source 5kW) so that the fusion width of melt zone becomes about 70mm.Afterwards, thus radio-frequency coil moved with the speed of 100mm per hour this melt zone moved about 900mm.At this moment, indoor pressure is 5 * 10
-6To 9 * 10
-6Pa.Measure the temperature of melt zone through radiation thermometer.The result is 800 ℃ to 660 ℃.
Afterwards, thus little by little reducing high frequency output solidifies this melt zone.
With indoor remain vacuum in, radio-frequency coil is moved to fusion zero position (this position is the position that at first forms melt zone), and with aluminium starting material heating and the fusion zero position once more fusion to form melt zone.Purify through moving this melt zone repeat region fusion.When melt zone is carried out three sub-region fusions and purifies (3 passage) with the translational speed of the fusion width of about 70mm and 100mm/ hour; Become even basically from the fusion initial section to the shape of accomplishing section, and keep uniform shape (in the process of 7 passages of mentioning below) from that time.
Afterwards, carry out the zone melting purification of 7 passages with the fusion width of the about 50mm of melt zone and 60mm/ hour translational speed.Based on the raw-material sectional dimension w of aluminium that will purify, the fusion width is that w * 2.8 are to w * 3.9.
After accomplishing altogether 10 passages, this chamber is to atmosphere opening, and afterwards aluminium removed the aluminium with the about 950mm of length that obtains to purify.
The aluminium that is obtained is cut out, and to carry out the glow discharge mass spectrometry composition analysis with identical as stated method.The result provides in table 1.
Table 1
Unit: ppm, in mass
| Comparative example 1 | Comparative example 2 | |
|
Embodiment 3 | |
| Li | 0.016 | ＜0.001 | ＜0.001 | ＜0.001 | |
| Be | 0.042 | ＜0.001 | ＜0.001 | ＜0.001 | |
| B | 1.5 | 2.8 | 0.019 | 0.007 | 0.001 |
| Na | 1.4 | 0.012 | 0.001 | 0.001 | |
| Mg | 5.2 | 0.1 | 0.48 | 0.10 | 0.001 |
| Si | 200 | 25 | 2.3 | 0.34 | 0.003 |
| K | ＜0.001 | 0.013 | 0.008 | 0.008 | |
| Ca | 1.3 | 0.002 | 0.002 | 0.003 | |
| Ti | 29 | 0.7 | 0.060 | 0.027 | 0.031 |
| V | 53 | 2.2 | 0.023 | 0.027 | 0.023 |
| Cr | 3.9 | 2.1 | 0.025 | 0.026 | 0.022 |
| Mn | 2.1 | 2.1 | 0.007 | 0.004 | 0.006 |
| Fe | 230 | 12 | 0.60 | 0.089 | 0.001 |
| Ni | 0.19 | 0.018 | 0.004 | 0.001 | |
| Co | 13 | 0.3 | ＜0.001 | ＜0.001 | ＜0.001 |
| Cu | 0.72 | 1 | 1.1 | 0.14 | 0.016 |
| Zn | 13 | 7 | 0.22 | 0.002 | 0.001 |
| Ga | 93 | 12 | 0.006 | 0.001 | 0.001 |
| As | 0.023 | 0.029 | 0.001 | 0.001 | |
| Zr | 4.8 | 0.023 | 0.030 | 0.036 | |
| Mo | 0.35 | ＜0.001 | ＜0.003 | ＜0.004 | |
| Ag | 1.1 | ＜0.001 | ＜0.001 | ＜0.001 | |
| Cd | ＜0.001 | 0.002 | 0.002 | 0.002 | |
| In | 0.009 | ＜0.001 | ＜0.001 | ＜0.001 | |
| Sn | 1.1 | 0.001 | 0.001 | 0.002 | |
| Sb | ＜0.001 | ＜0.001 | ＜0.001 | ＜0.001 | |
| Ba | 0.004 | ＜0.001 | ＜0.001 | ＜0.001 | |
| La | 0.038 | 0.045 | 0.001 | 0.001 | |
| Ce | 0.095 | 0.17 | 0.001 | 0.001 | |
| Pt | ＜0.001 | 0.002 | 0.001 | 0.001 | |
| Hg | ＜0.001 | 0.001 | 0.003 | 0.002 | |
| Pb | 1.9 | 0.004 | 0.001 | 0.001 | |
| Bi | ＜0.001 | 0.001 | 0.001 | 0.001 | |
| Amount to | 669 | 67 | ＜5.4 | ＜8.3 | ＜0.18 |
Afterwards, thus with the raffinal of the embodiment 1 to 3 that obtains cut respectively with obtain to be measured as separately 6mm wide * 6mm is thick * 100mm long be used for the stringy material.In order to remove the pollution element owing to the surface cutting that is used for the stringy material, (hydrochloric acid: pure water=1: 1) acid of preparation was carried out acid etching 1 hour, washed more than 30 minutes with flowing water afterwards with ratio in use.
Be used for the stringy material through using the rolling and wire drawing of grooved roll with what obtain to draw diameter as 0.5mm.To be fixed to quartzy anchor clamps through the sample that wire drawing obtains, 500 ℃ of maintenances 3 hours in a vacuum, and afterwards with its stove internal cooling to obtain to be used for the sample of resistivity measurement.
In addition; To (make as the commercially available high purity copper of the sample of comparative example 3 with 5N grade purity by NewMet Koch; 99.999%Cu, diameter 0.5mm) be fixed to quartzy anchor clamps, and use organic solvent washing; 500 ℃ of maintenances 3 hours in a vacuum, and afterwards with its stove internal cooling to obtain to be used for the sample of resistivity measurement.
(2) derivation of resistivity
The measurement of resistivity
For the sample of embodiment 1 to 3 and comparative example 3, actual measurement resistivity.
After the sample that is obtained being immersed in the liquid helium (4.2K), use four-wire method, be changed to 15T through the magnetic field that will be applied to sample from magnetic flux density 0T (not applying magnetic field), with measured resistivity.
Direction with the parallel longitudinal of sample applies magnetic field.
The calculating of resistivity
About the comparative example 1 and comparative example 2 with the composition shown in the table 1, use disclosed following equality (4) in document calculates: R.J.Corruccini, NBS Technical Note, 218 (1964).In equality (4), Δ ρ
HIt is the increasing amount of resistivity in the magnetic field.ρ
RTBe the resistivity under the room temperature when not applying magnetic field, and because in the raffinal with the above purity of 3N, can it be treated as specified value basically, it is set to 2,753n Ω cm.ρ is the resistivity of 4.2K when not applying magnetic field, and depends on purity and very big variation is arranged.Therefore, use following experimental value: 9.42n Ω cm (RRR=285) in 4N-Al, and be 117n Ω cm (RRR=23) in 3N-Al.These equalities are under the longitudinally situation of magnetic field perpendicular to sample, to obtain.Yet, not obtaining similar equality because be parallel in magnetic field under the situation longitudinally of sample, these equalities are used for contrast.RRR also is called as Residual Resistivity Ratio, and is the ratio of resistivity of resistivity and the helium temperature (4.2K) of 297K.
Wherein
H
*＝H/100ρ
RT/ρ
R
The intensity (tesla) in magnetic field that H=applies
ρ
RT=resistivity when room temperature does not apply magnetic field
The resistivity of ρ=when not applying magnetic field
Reference citation about resistivity
About comparative example 4 to 6, resistivity obtains from document: Fujiwara S. etc., Int.Conf.Process.Mater.Prop.1st (1993), 909-912.In these data in literature, do not describe magnetic field apply direction and sample vertically between relation.
Thereby the value of the resistivity of embodiment that draws 1 to 3 and comparative example 1 to 6 provides in table 2.
Table 2
As conspicuous from table 2; The sample of comparative example 2 is corresponding to the thermal conductor of being processed by traditional aluminium (4N grade); Compare with the situation that does not have magnetic field (0T), the increase resistivity increase along with magneticstrength (magnetic flux density) increases to about 3 times in 15T resistivity.
On the contrary, in embodiment 1 to 3, resistivity is very little under the state that does not have magnetic field, as with comparative example 2 relatively be below 1/10th, even and to increase the increase of resistivity also very little in magnetic field.
In embodiment 1 (5N grade), with the situation that does not have magnetic field relatively, the resistivity of 15T slightly increases (about 1.5 times), and is apparent that the increase of the resistivity that is relatively caused by magnetic field with comparative example 2 is very little.
In embodiment 2 (6N grade), compare with the situation that does not have magnetic field, even also only slightly increase (in 10%) in 15T resistivity.When magnetic flux density is in 1 to 12T scope, compare with the situation that does not apply magnetic field, the numerical value of resistivity reduces, and so demonstrates significant magneto-resistor restraining effect.
For embodiment 3 (6N8 grade), even, reduce with the situation comparing electrical resistance rate that does not have magnetic field, and so demonstrate significant magneto-resistor restraining effect in any magnetic flux density of 1 to 15T.
Fig. 1 be show the specific conductivity index and the magnetic field (magnetic flux density) that applied between the figure of mutual relationship.The specific conductivity index is the index of expression based on the specific conductivity size of the respective sample of comparative example 2, and comparative example 2 demonstrates the resistivity of aluminium in high-intensity magnetic field of the purity with 4N.That is, in each magnetic flux density, the specific conductivity index is through confirming divided by the resistivity value of each sample with the resistivity value of comparative example 2.This exponential numerical value is big more, runs off look with the sample comparison of comparative example 2 in this magnetic flux density conductive properties.
Because the sample of embodiment shows extremely significant effect, the specific conductivity index of ordinate zou is represented through logarithm.
As can obviously finding out from Fig. 1, even under the situation that does not have magnetic field, the sample of embodiment has also demonstrated with comparative example 2 and has compared up to about 13 to 28 times specific conductivity.When applying magnetic field, to compare with comparative example 2, specific conductivity increases.(embodiment 1) and further increases in the 15T specific conductivity to 65 times (embodiment 3) up to 16 times in the 1T specific conductivity, because it is that 26 times (embodiment 1) are to 96 times (embodiment 1).
As can obviously finding out from Fig. 1, arbitrarily copper sample (comparative example 3 to 6) show under the dextrad curve and, along with the increase of magneticstrength, compare with comparative example 2, magneto-resistance effect increases.That is, what found is, under the copper situation; Owing to can not suppress magneto-resistor; Even purity be increased to 6N grade specific conductivity also descend (obviously draw from table 1, in the sample of comparative example 3 to 6, with resistivity under the situation that does not have magnetic field relatively; Resistivity during 15T increases to 5 to 18 times), and the inventor finds that through increasing the effect that can suppress specific conductivity reduction in the magnetic field more than purity to the 99.999 quality % be that aluminium is peculiar.
Unclear why can not showing through the highly purified magneto-resistor of bringing copper suppressed effect and can be shown aluminium.Yet, can infer that difference by the resistivity factor causes.That is, certificate thinks that the main resistivity of high purity copper is the conduction electron scattering owing to crystal boundary or dislocation, even and through highly purified resistivity also only slightly variation, thereby and also only slightly variation of magneto-resistor.On the other hand, the main resistivity factor of raffinal is the conduction electron scattering that is produced by impurity atoms, and through the highly purified resistivity factor that reduced.Therefore, according to thinking that the aluminium with the above purity of 5N can show the excellent specific property that resistivity increases hardly in magnetic field.Yet the mechanism of this supposition does not limit the scope of the invention.
Afterwards, calculate the thermal conductivity of each sample by the result of table 2.
The result of the result of table 2 and the Residual Resistivity Ratio RRR that calculated by above-mentioned equality (3) provides in table 3.Numerical value (being the resistivity of 4.2K) in the use table 2 is as the ρ of equality (3)
TAs stated, in copper and aluminium, ρ
297KThe influence in the magnetic field that receives purity hardly and apply from the outside, and be constant basically, and in high purity metal, can be used as the SP processing.Therefore, use 2,753n Ω cm is as the ρ of aluminium
297K, and using 1,500n Ω cm is as the ρ of copper
297K
Table 3
Afterwards, thermal conductivity is calculated in RRR value in the use table 3 and equality (1) and (2).
Fig. 2 be show thermoelectric conductance and the magnetic field (magnetic flux density) that applied between the figure of relation.
As can obviously drawing from Fig. 2; Thermal conductivity reduces when the intensity of the high-intensity magnetic field in all comparative examples increases, and said all comparative examples comprise corresponding to the comparative example 2 of the thermal conductor of being processed by traditional aluminium (4N grade) and corresponding to the comparative example 6 of the thermal conductor of being processed by traditional copper (6N grade).In the magnetic flux density of 15T, though in demonstrating comparative example under the situation of the comparative example 3 of high heat conductance thermal conductivity also be merely 1,238W/m/K.
On the contrary, in embodiment 1 to 3, even magneticstrength increases, the decline of thermal conductivity also is pressed.
In embodiment 1, it is stable up to 15T that thermal conductivity reduces the back at 1T, even when 15T, represent high heat conductance (about 9,500W/m/K).
In embodiment 2, the contrast when not applying magnetic field increases in thermal conductivity in the scope of 1T to 12T, and even 15T represent high heat conductance (about 25,000W/m/K).
In embodiment 3, the situation when not applying magnetic field relatively, thermal conductivity increases in the scope of 1T to 15T, and even 15T show very high thermal conductivity (about 33,000W/m/K).
Thereby the thermal conductivity that use to obtain is calculated when the end with sample links to each other with refrigerator and the other end applied heat and import the temperature difference in the generation of the two ends of sample.
More specifically; When the wide w that will record is that 100mm, long L are 400mm, thickly link to each other with the cooling class of the refrigerator that is cooled to about 4K and when the other end that separates 400mm applied the heat input Q of 2W, calculate the temperature difference that produces between the two ends for an end of 0.5mm lengthy motion picture shape thermal conductor.
Temperature difference T between the two ends confirms through equality (5).
ΔT＝Q×(L/1,000)/(w/1,000)/(t/1,000)/λ (5)
Wherein
Q: heat input (W)
L: the length of sheet sample (mm)
W: the width of sheet sample (mm)
T: the thickness of sheet sample (mm)
λ: thermal conductivity (W/m/K)
Fig. 3 is the temperature difference at the such sheet sample two ends that obtain of expression and the figure of the relation between magnetic field (magnetic flux density).Because the greatest differences between embodiment sample and the comparative sample, the temperature difference of ordinate zou is represented by logarithm.
In embodiment 1 to 3, almost do not recognize the temperature difference.Even at 15T, Δ T=1.7K in embodiment 1, Δ T=0.6K in embodiment 2, and in embodiment 3 Δ T=0.5K.
On the contrary, in any comparative example, along with the increase of magneticstrength, Δ T also increases.In comparative example, in the comparative example 3 of the Δ T of 15T minimum, Δ T is 13K equally.Δ T corresponding to the comparative example 2 of the thermal conductor of being processed by conventional aluminum (4N grade) is 42K.
In addition, these numerical value are the numerical value that obtains under the temperature dependent situation of thermal conductivity λ not considering, and are considering that Δ T further increases under the temperature dependent situation.
By this way, when use in addition in freezing temp and high-intensity magnetic field, have high heat conductance and can demonstrate excellence heat conduction property according to thermal conductor of the present invention the time, relatively can reduce xsect with traditional thermal conductor.Therefore, can comprise the miniaturized and the weight saving of the plant and instrument of superconducting magnet.
According to the present invention, a kind of thermal conductor with outstanding heat conduction property can be provided, itself in addition for example below the liquid nitrogen temperature (77K), especially in the high-intensity magnetic field of the above magnetic flux density of 1T, have high heat conductance at low temperature at the cryogenic temperature below the 20K.
Claims (5)
1. thermal conductor that in the magnetic field of the magnetic flux density of the low temperature below the 77K more than 1T, uses, said thermal conductor comprise and have the above purity of 99.999 quality % and have the aluminium of the iron level below the 1ppm in mass.
2. thermal conductor according to claim 1, wherein said aluminium have the above purity of 99.9999 quality %.
3. thermal conductor according to claim 1, wherein said aluminium have the above purity of 99.99998 quality %.
4. according to each the described thermal conductor in the claim 1 to 3, wherein said aluminium contains intermetallic compound Al
3Fe.
5. thermal conductor that is used to cool off superconducting magnet, the said thermal conductor that is used for cooling off superconducting magnet uses each the described thermal conductor according to claim 1 to 4.
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|---|---|---|---|
| JP2011101767A JP2012234938A (en) | 2011-04-28 | 2011-04-28 | Low-temperature heat transfer material |
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| JP5845072B2 (en) * | 2011-12-05 | 2016-01-20 | 住友化学株式会社 | Aluminum facing material and method for producing the same |
| JP7209492B2 (en) * | 2018-08-17 | 2023-01-20 | 住友化学株式会社 | Aluminum clad material and its manufacturing method |
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| US5573861A (en) * | 1993-07-06 | 1996-11-12 | Sumitomo Chemical Co., Ltd. | High purity aluminum conductor used at ultra low temperature |
| JP2010106329A (en) * | 2008-10-31 | 2010-05-13 | Sumitomo Chemical Co Ltd | Extremely-low-temperature heat transfer material |
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| JPS57145957A (en) * | 1981-03-03 | 1982-09-09 | Sumitomo Electric Ind Ltd | Aluminum alloy for stabilizing superconduction |
| JPH0798987B2 (en) * | 1987-05-27 | 1995-10-25 | 古河電気工業株式会社 | Method for producing aluminum alloy sheet with excellent surface quality |
| JPH0211733A (en) * | 1988-06-28 | 1990-01-16 | Showa Electric Wire & Cable Co Ltd | Manufacture of nb3 sn superconducting wire by internal diffusing method |
| US5357756A (en) * | 1993-09-23 | 1994-10-25 | Martin Marietta Energy Systems, Inc. | Bipolar pulse field for magnetic refrigeration |
| JPH08335408A (en) * | 1995-06-08 | 1996-12-17 | Fujikura Ltd | Fatigue-resistant conductive wire |
| JP3731231B2 (en) * | 1995-11-30 | 2006-01-05 | 株式会社日立メディコ | Superconducting magnet device |
| US5917393A (en) * | 1997-05-08 | 1999-06-29 | Northrop Grumman Corporation | Superconducting coil apparatus and method of making |
| US6807812B2 (en) | 2003-03-19 | 2004-10-26 | Ge Medical Systems Global Technology Company, Llc | Pulse tube cryocooler system for magnetic resonance superconducting magnets |
| JP2007263621A (en) * | 2006-03-27 | 2007-10-11 | Kobe Steel Ltd | Coil for magnetic resonance detection and its manufacturing method |
| JP5086592B2 (en) * | 2006-09-25 | 2012-11-28 | 住友化学株式会社 | Cold work material |
| JP5086598B2 (en) * | 2006-10-06 | 2012-11-28 | 住友化学株式会社 | Cold work material |
| WO2009063532A1 (en) * | 2007-11-14 | 2009-05-22 | Nippon Light Metal Company, Ltd. | Aluminum etched plate for electrolytic capacitor |
| JP5098751B2 (en) * | 2008-03-31 | 2012-12-12 | 住友化学株式会社 | Manufacturing method of ultra-high purity aluminum high rolled material |
| JP5098753B2 (en) * | 2008-03-31 | 2012-12-12 | 住友化学株式会社 | Manufacturing method of ultra-high purity aluminum high rolled material |
| JP5098750B2 (en) * | 2008-03-31 | 2012-12-12 | 住友化学株式会社 | Method for producing high-purity aluminum rolled material |
| US8002912B2 (en) * | 2008-04-18 | 2011-08-23 | United Technologies Corporation | High strength L12 aluminum alloys |
| JP5355968B2 (en) | 2008-09-09 | 2013-11-27 | 本田技研工業株式会社 | Electric power steering device |
| JP5478899B2 (en) * | 2009-01-07 | 2014-04-23 | 住友化学株式会社 | High purity aluminum material |
| US8253416B2 (en) * | 2009-03-10 | 2012-08-28 | Time Medical Holdings Company Limited | Superconductor magnetic resonance imaging system and method (super-MRI) |
| JP2010232432A (en) * | 2009-03-27 | 2010-10-14 | Kobe Steel Ltd | Magnetic field generator and method for using the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5573861A (en) * | 1993-07-06 | 1996-11-12 | Sumitomo Chemical Co., Ltd. | High purity aluminum conductor used at ultra low temperature |
| JP2010106329A (en) * | 2008-10-31 | 2010-05-13 | Sumitomo Chemical Co Ltd | Extremely-low-temperature heat transfer material |
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