CA1300677C - Method of forming glass bonded joint of beta-alumina and other ceramic and joint formed thereby - Google Patents
Method of forming glass bonded joint of beta-alumina and other ceramic and joint formed therebyInfo
- Publication number
- CA1300677C CA1300677C CA000560372A CA560372A CA1300677C CA 1300677 C CA1300677 C CA 1300677C CA 000560372 A CA000560372 A CA 000560372A CA 560372 A CA560372 A CA 560372A CA 1300677 C CA1300677 C CA 1300677C
- Authority
- CA
- Canada
- Prior art keywords
- alumina
- beta
- glass
- alpha
- joint
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000011521 glass Substances 0.000 title claims abstract description 46
- 229910000873 Beta-alumina solid electrolyte Inorganic materials 0.000 title claims abstract description 35
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000000919 ceramic Substances 0.000 title abstract description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000007767 bonding agent Substances 0.000 claims abstract description 16
- 239000000654 additive Substances 0.000 claims abstract description 7
- 239000011324 bead Substances 0.000 claims abstract description 7
- 239000007787 solid Substances 0.000 claims abstract description 4
- 230000004927 fusion Effects 0.000 claims abstract description 3
- 230000000149 penetrating effect Effects 0.000 claims abstract description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 4
- 239000011734 sodium Substances 0.000 claims description 4
- 229910052708 sodium Inorganic materials 0.000 claims description 4
- 239000007784 solid electrolyte Substances 0.000 claims 2
- 239000005864 Sulphur Substances 0.000 claims 1
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 15
- 238000010438 heat treatment Methods 0.000 abstract description 10
- 239000007822 coupling agent Substances 0.000 abstract description 7
- BNOODXBBXFZASF-UHFFFAOYSA-N [Na].[S] Chemical compound [Na].[S] BNOODXBBXFZASF-UHFFFAOYSA-N 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 239000003566 sealing material Substances 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 230000035515 penetration Effects 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- 229960005349 sulfur Drugs 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 235000001508 sulfur Nutrition 0.000 description 4
- 238000001000 micrograph Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000000137 annealing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000001609 comparable effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229940035564 duration Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000036647 reaction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- RBWSWDPRDBEWCR-RKJRWTFHSA-N sodium;(2r)-2-[(2r)-3,4-dihydroxy-5-oxo-2h-furan-2-yl]-2-hydroxyethanolate Chemical compound [Na+].[O-]C[C@@H](O)[C@H]1OC(=O)C(O)=C1O RBWSWDPRDBEWCR-RKJRWTFHSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
- C04B37/003—Joining burned ceramic articles with other burned ceramic articles or other articles by heating by means of an interlayer consisting of a combination of materials selected from glass, or ceramic material with metals, metal oxides or metal salts
- C04B37/005—Joining burned ceramic articles with other burned ceramic articles or other articles by heating by means of an interlayer consisting of a combination of materials selected from glass, or ceramic material with metals, metal oxides or metal salts consisting of glass or ceramic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
- H01M10/39—Accumulators not provided for in groups H01M10/05-H01M10/34 working at high temperature
- H01M10/3909—Sodium-sulfur cells
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
- C04B2235/667—Sintering using wave energy, e.g. microwave sintering
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/02—Aspects relating to interlayers, e.g. used to join ceramic articles with other articles by heating
- C04B2237/10—Glass interlayers, e.g. frit or flux
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/34—Oxidic
- C04B2237/343—Alumina or aluminates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
- C04B2237/76—Forming laminates or joined articles comprising at least one member in the form other than a sheet or disc, e.g. two tubes or a tube and a sheet or disc
- C04B2237/765—Forming laminates or joined articles comprising at least one member in the form other than a sheet or disc, e.g. two tubes or a tube and a sheet or disc at least one member being a tube
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Secondary Cells (AREA)
Abstract
METHOD OF FORMING GLASS BONDED
JOINT OF BETA-ALUMINA AND OTHER
CERAMIC AND JOINT FORMED THEREBY
ABSTRACT OF THE INVENTION
A method of producing a joint between a beta-alumina electrolyte tube and alpha-alumina flange with a glass bonding agent in a solid annular bead form devoid of additives such as a coupling agent or the like capable of being heated when subjected to microwave energy which com-prises utilizing in the heating step a source of microwave energy rather than a gas flame or electrical resistance heat source so as to heat the beta-alumina tube by microwave energy for a time period sufficient to enable the heat generated in the beta-alumina tube to be conducted tog lass bead and the alpha-alumina flange and heat the glass bead to a temperature above the glass deformation point, and allowing the tube to cool to solidify the glass bead in intimately penetrating relation to the surfaces of the beta-alumina tube and alpha-alumina flange engaged thereby so that the glass forms a bond between the beta-alumina tube and the alpha-alumina flange characterized by a fusion of the glass within the engaged beta-alumina and alpha-alumina.
JOINT OF BETA-ALUMINA AND OTHER
CERAMIC AND JOINT FORMED THEREBY
ABSTRACT OF THE INVENTION
A method of producing a joint between a beta-alumina electrolyte tube and alpha-alumina flange with a glass bonding agent in a solid annular bead form devoid of additives such as a coupling agent or the like capable of being heated when subjected to microwave energy which com-prises utilizing in the heating step a source of microwave energy rather than a gas flame or electrical resistance heat source so as to heat the beta-alumina tube by microwave energy for a time period sufficient to enable the heat generated in the beta-alumina tube to be conducted tog lass bead and the alpha-alumina flange and heat the glass bead to a temperature above the glass deformation point, and allowing the tube to cool to solidify the glass bead in intimately penetrating relation to the surfaces of the beta-alumina tube and alpha-alumina flange engaged thereby so that the glass forms a bond between the beta-alumina tube and the alpha-alumina flange characterized by a fusion of the glass within the engaged beta-alumina and alpha-alumina.
Description
~30~6~77 .
METHOD OF FORMING GLASS BONDE~
JOINT OF BETA--ALUMINA AND OTHER
CE:RAMIC AND JOINT FORMED THEREBY
This invention relates to sodium sulfur bat-teries and more particularly to methods of producing a joint between a body of beta-alumina such as a sodiu~ sul-fur cell electrolyte tube and a body of alpha-alumina such as an insulating ring for the electrolyte tube with a glass bonding agent.
Sodium sulfur batteries are known. The known characteristic of sodium sulfur batteries is that they provide a highly desirable power output to weight ratio.
The known disadvantage of sodium sulfur batteries is that they are difficult to manufacture economically so as to operate with any high degree of reliability. If the joint between the electrolyte tube and the insulating ring for the tube of the sodium sulfur cell fails, the cell itself is essentially in a fail mode. Heretofore, this joint has been produced by assembling the electrolyte tube, the in-sulating ring, and a ring of glass bonding agent and then subjecting the assembled elements of the joint to heat from a gas flame or electrical resistant heat source.
Typically, the joint is subjected to a maximum temperature of 1100~C. for a treatment period of approximately sixteen hours, a significant portion of which constitutes an an-nealing step. The energy consumption is substantially high both because of the magnitude of the heating step and particularly the long duration of the annealing step.
There is sufficient excess cost involved in the process of producing the joint mentioned above and sufficient lack of reliability in the joint so produced as to establish a need for a economical method which- will produce a more reliable joint.
It is an object of the present invention to ful-fill the above-described need. In accordance with the principles of the present invention, this objective is achieved by utiliæing in the heating step a source of microwave energy rather than a gas flame or electrical re-sistance heat source. The beta-alumina body exemplified ~3~C~677 by the electrolyte tube and the alpha-alumina body exem-plified by the insulating ring together with the glass body constituting the bonding agent engaged to surfaces of the other two bodies is subjected to microwave energy from the microwave source so as to heat the beta-alumina body by microwave energy for a time period sufficient to enable the heat generated i~ the beta-alumina body to be con-ducted to said glass body and the alpha-alumina body and heat the glass body to a temperature above the glass deformation point. Thereafter, the bodies are allowed to cool to solidify the glass body in intimately penetrating relation to the surface of the beta-alumina and alpha-alumina engaged thereby so that the glass body forms a bond between the beta-alumina body and the alpha-alumina body characterized by a fusion of the glass within the en-gaged betaalumina and alpha-alumina to an extent greater than that occurring when all three bodies are subjected to heat from a gas flame or electrical resistant heat source for the predetermined time period heretofore used to ac-complish the joint. The time period to which the bodies are subject to microwave energy is (1) not substantially longer than that re~uired to heat the glass to its defor-mation point and (2) significantly less than the predeter-mined time period heretofore utilized in heating the joint with a yas flame or electrical resistance heat source.
It is recognized that it has been proposed here-tofore to effect a ceramic-glass-ceramic seal by microwave heating. See, for example, U.S. Patents Nos. 4,529,856, 4,529,857, and 4,606,748. ~owever, it will be noted that in all of these disclosures there is no specific contem-plation of the utilization of a beta-alumina as the ~eramic material. The essential characteristic of the microwave heating process disclosed in these patents is the provision of a coupling agent in the sealing material or bonding agent. Specifically, the sealing material is a slurry of glass and the coupling agent is added thereto 1~00~77 for the specific purpose of creating a heat in the glass sealing material in response to the application of micro-wave energy so as to accomplish the melting of the glass sealing material with respect to the two ceramic work-pieces to be joined. The utilization of coupling agents or other additives in the glass bonding agent of a sulfur cell joint is disadvantageous in that such additives would increase internal porousity and would detrimentally affect reliability and durability of the joint in operation.
Consequently, the method taught in the above-noted patents would be clearly unsuitable for producing a joint between a beta-alumina electrolyte tube and an alpha-alumina in-sulating ring such as herein contemplated. Nevertheless, applicant has found that such a joint can be produced in accordance with the principles of the present invention without the essential coupling agent of the prior art and its function. Indeed, the present invention relies upon the direct microwave heating of the beta-alumina electro-lyte tùbe and the heating of the glass sealing material or bonding agent primarily through heat conduction and con-vection from the beta~alumina body and through the alpha-alumina body which preferably is also heated by conduction and convection ~rom the beta-alumina body.
While the present invention has been developed to fulfill the particular need with respect to joints in sodium sulfur battery cells, the method has applicability in producing any joint between a body of beta-alumina and an electrically insulating ceramic body with the use of a heat activated ceramic bonding agent in any situation where the need for purity in the joint requires the use of a heat activated ceramic bonding agent devoid of additives such as coupling agents capable of being heated when sub-ject to microwave energy.
Another object of the present invention is the provision of an improved glass bonding agent joint between a beta-alumina electrolyte tube and an alpha-alumina insulating ring, the improved joint having the character-istics as shown in the attached drawings or as produced in accordance with the principles of the method of the pres-ent invention.
These and other objects of the present invention will become more apparent during the course of the follow-ing detailed description and appended claims.
The invention may best be understood with refer-ence to the accompanying drawings wherein an illustrative embodiment is shown.
In the drawings:
Figure 1 illustrates an assembled beta-alumina electrolyte tube, alpha-alumina insulating ring and glass bonding agent ring inverted as they would be placed in the microwave oven in accordance with the principles of the present invention;
Figure 2 is a graph illustrating the processing temperature and processing time of the present method as compared with the conventional method utilizing a gas flame or electrical resistance heat source;
Figure 3 is a scanning electron microscope mi-crophotograph at 2Dx of a joint constructed in accordance with the present invention;
Figure 4 is a scanning electron microscope mi-crophotograph similar to Figure 3 showing a comparable joint constructed in accordance with conventional prac-tice; ', Figure 5 is an SI map of the seal showing thecontour of the:glass with high silicon content of the present joint of Figure 3;
Figure 6 is an 5I map similar to Figure 5 o~ the ,prior art joint of Figure,4;
Figure 7 is a scanning electron microscope and EDAX microphotograph sho~ing an SI line scan of a magni-tude of 500x of the present joint of Figure 3; and Fisure 8 is a microphotograph similar to Figure 7 of the prior art joint of Figure 4.
1~1D0~;77 Referring now more particularly to the drawings there is shown in Figure 1 two components of a sodium sul-fur battery cell, one a beta-alumina electrolyte tube,.
generally indicated at 10 and the other an insulating ring, generally indicated at 12, for the tube 10. The tube 10 is in the form of a cylinder body 14 having a dome 16 closing an end thereof. The insulating ring 1~ is an alpha alumina body forming an exterior flange for the electrolyte tube 10. The components are joined in accor-dance with the principles of the present invention and once joined are used in a sodium sulfur battery in accor-dance with the disclosure contained in U.S. Patent ~,207,386.
It will be noted that the electrolyte tube when embodied in the bat-tery cell is inverted from the position shown in Figure 1 so that the dome 14 is -at the lower end thereof and the flange is at the upper end thereof. It will be noted that for example in ~igure 1 of Patent 4,207,386 the electro-lyte tube is identified by the n~meral 2 and the flange is identified by the.numeral 12.
The insulating ring or flange 20 of the present invention includes an interior cylindrical surface 18 which, in the orientation shown in Figure 1 of the present .drawings,.extends upwardly from the lower surface of the ring 12. The cylindrical surface 18 intersects with a frusto-conical surface.20 which terminates at the upper surface of the insulating ring. The insulating ring 12 is assembled on the open end of the electrolyte tube 10 by engaging the interior surface 18 of the insulating ring with a portion of the exterior periphery of the cylinder 14 forming the major part of the tube 10. The frusto-con-ical surface 20 defines with the axially coextensive ex-terior surface of the cylinder 14 an annular recess 22 which is essentially wedge-shaped in cross-sectional con-figuration. Mounted within the recess 22, as shown in 131D06~77 Figure 1, is a bonding agent, such as glass. The g~ass utilized in the bonding agent is devoid of any additives particularly additives such as coupling agents or the like capable of being heated when s~bjected to microwave energy.
The glass bonding agent, as shown, is a solid body 24 having a solid form shape which is essentially an annular bead with a wedge shaped cross-sectional configur-ation corresponding with the wedge shaped cross-section of the recess 22 which receives the same.
In a~eordance with the principles of the present method, the assembled components as shown in ~igure 1 are then placed in an industrial type microwave oven. An ex-ample of a microwave oven which may be utilized is a Lit-ton*Model 1521 operating at 2.45 gHz with a power output of 700 watts. Preferably, the assembly as shown in Pigure 1 is first placed in an insulating enclosure, such as a closely dimensional ceramic tube which is transparent for microwaves and is heat resistant at the temperature of bonding. The insulatina enclosure is desirable, partic-ularly to reduce sodium loss when dealing with sodium sul-fur battery parts, although it may be dispensed with if desired. The assembly in the insulating enclosure was ex-posed to microwaves for a short period of time. Only a few minutes (e.g. 12 minutes) was required to heat the beta-alumina tube to the required temperature of approxi-mately 1100C. The glass body and the alpha-alumina were heated due primarily to thermal conduction from the beta-alumina and to some extent by convection as well. Only a short period of time was required to accomplish cooling ~e.g. 18 minutes). As a result of the glass melting and subsequent cooling a strong hermetic seal was formed.
The processing time within the microwave oven in acc~rdance with the principles of the present invention is illustrated graphically in ~igure 2 and it will be noted that in the scale shown the application temperature-time * Trade-mark ~3~
relationship represents a relatively high spike configura-tion. Also included on the graph of Figure 2 is the tem-perature time relationship when the same assembly as shown in Figure 1 is conventionally heated using a gas flame or electrical resistant heat source. As shown on the graph, more than four times more energy is utilized with the con-ventional gas flame or electrical resistance heat source than with the microwave energy in accordance with the principles of the present invention. Moreover, the dura-tion of the prior art treatment was reduced by more than a factor of 40 in practicing-the principles of the present invention.
By utilizing the procedures of the present in-vention a joint with superior properties is obtained com-pared to the joint made by conventional heating in a gas or electric furnace. The difference in the quality of the joint is attributed to the different kinetics of the reac-tion causing extensive diffuslon of glass into the alpha-alumina ceramics and resulting in a different microstruc-ture of the joint when microwave heating is applied.
Figure 3 illustrates a scanning electron micro-scope microphotograph at 20K of the joint produced in ac-cordance with the principles of the present invention and it will be noted that it is of comparable or better quality when compared with the conventional joint shown in Figure 4.
Figure 5 is a silicon map of the joint of the present invention such as shown in Figure 3 and it will be noted that the configuration of the glass in the joint differs from the configuration in the prior art joint shown in Figure ~ which has a distinct tail or a flow of glass beyond the recess.
~ inally, a comparison of the silicon line scan at a magnification of 500x is shown in Figure 7 of the joint constructed in accordance with the principles of the present invention. It is significant to note that ~300677 substantial penetration of silicon into the alpha-alumina is shown in the righthand portion of the figure. The com-parable penetration of the prior art joint is shown in Figure 8 and it will be noted that significantly less pen-etration of silicon into the alpha-alumina is indicated.
The difference in configuration as depicted in Figures 5 and 6 and the difference in the penetration as depicted in Figures 7 and 8 demonstrate a highly desirable joint has been produced by the present invention in comparison with prior art procedures.
It thus will be seen that the objects of this invention have been fully and effectively accomplished.
It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.
METHOD OF FORMING GLASS BONDE~
JOINT OF BETA--ALUMINA AND OTHER
CE:RAMIC AND JOINT FORMED THEREBY
This invention relates to sodium sulfur bat-teries and more particularly to methods of producing a joint between a body of beta-alumina such as a sodiu~ sul-fur cell electrolyte tube and a body of alpha-alumina such as an insulating ring for the electrolyte tube with a glass bonding agent.
Sodium sulfur batteries are known. The known characteristic of sodium sulfur batteries is that they provide a highly desirable power output to weight ratio.
The known disadvantage of sodium sulfur batteries is that they are difficult to manufacture economically so as to operate with any high degree of reliability. If the joint between the electrolyte tube and the insulating ring for the tube of the sodium sulfur cell fails, the cell itself is essentially in a fail mode. Heretofore, this joint has been produced by assembling the electrolyte tube, the in-sulating ring, and a ring of glass bonding agent and then subjecting the assembled elements of the joint to heat from a gas flame or electrical resistant heat source.
Typically, the joint is subjected to a maximum temperature of 1100~C. for a treatment period of approximately sixteen hours, a significant portion of which constitutes an an-nealing step. The energy consumption is substantially high both because of the magnitude of the heating step and particularly the long duration of the annealing step.
There is sufficient excess cost involved in the process of producing the joint mentioned above and sufficient lack of reliability in the joint so produced as to establish a need for a economical method which- will produce a more reliable joint.
It is an object of the present invention to ful-fill the above-described need. In accordance with the principles of the present invention, this objective is achieved by utiliæing in the heating step a source of microwave energy rather than a gas flame or electrical re-sistance heat source. The beta-alumina body exemplified ~3~C~677 by the electrolyte tube and the alpha-alumina body exem-plified by the insulating ring together with the glass body constituting the bonding agent engaged to surfaces of the other two bodies is subjected to microwave energy from the microwave source so as to heat the beta-alumina body by microwave energy for a time period sufficient to enable the heat generated i~ the beta-alumina body to be con-ducted to said glass body and the alpha-alumina body and heat the glass body to a temperature above the glass deformation point. Thereafter, the bodies are allowed to cool to solidify the glass body in intimately penetrating relation to the surface of the beta-alumina and alpha-alumina engaged thereby so that the glass body forms a bond between the beta-alumina body and the alpha-alumina body characterized by a fusion of the glass within the en-gaged betaalumina and alpha-alumina to an extent greater than that occurring when all three bodies are subjected to heat from a gas flame or electrical resistant heat source for the predetermined time period heretofore used to ac-complish the joint. The time period to which the bodies are subject to microwave energy is (1) not substantially longer than that re~uired to heat the glass to its defor-mation point and (2) significantly less than the predeter-mined time period heretofore utilized in heating the joint with a yas flame or electrical resistance heat source.
It is recognized that it has been proposed here-tofore to effect a ceramic-glass-ceramic seal by microwave heating. See, for example, U.S. Patents Nos. 4,529,856, 4,529,857, and 4,606,748. ~owever, it will be noted that in all of these disclosures there is no specific contem-plation of the utilization of a beta-alumina as the ~eramic material. The essential characteristic of the microwave heating process disclosed in these patents is the provision of a coupling agent in the sealing material or bonding agent. Specifically, the sealing material is a slurry of glass and the coupling agent is added thereto 1~00~77 for the specific purpose of creating a heat in the glass sealing material in response to the application of micro-wave energy so as to accomplish the melting of the glass sealing material with respect to the two ceramic work-pieces to be joined. The utilization of coupling agents or other additives in the glass bonding agent of a sulfur cell joint is disadvantageous in that such additives would increase internal porousity and would detrimentally affect reliability and durability of the joint in operation.
Consequently, the method taught in the above-noted patents would be clearly unsuitable for producing a joint between a beta-alumina electrolyte tube and an alpha-alumina in-sulating ring such as herein contemplated. Nevertheless, applicant has found that such a joint can be produced in accordance with the principles of the present invention without the essential coupling agent of the prior art and its function. Indeed, the present invention relies upon the direct microwave heating of the beta-alumina electro-lyte tùbe and the heating of the glass sealing material or bonding agent primarily through heat conduction and con-vection from the beta~alumina body and through the alpha-alumina body which preferably is also heated by conduction and convection ~rom the beta-alumina body.
While the present invention has been developed to fulfill the particular need with respect to joints in sodium sulfur battery cells, the method has applicability in producing any joint between a body of beta-alumina and an electrically insulating ceramic body with the use of a heat activated ceramic bonding agent in any situation where the need for purity in the joint requires the use of a heat activated ceramic bonding agent devoid of additives such as coupling agents capable of being heated when sub-ject to microwave energy.
Another object of the present invention is the provision of an improved glass bonding agent joint between a beta-alumina electrolyte tube and an alpha-alumina insulating ring, the improved joint having the character-istics as shown in the attached drawings or as produced in accordance with the principles of the method of the pres-ent invention.
These and other objects of the present invention will become more apparent during the course of the follow-ing detailed description and appended claims.
The invention may best be understood with refer-ence to the accompanying drawings wherein an illustrative embodiment is shown.
In the drawings:
Figure 1 illustrates an assembled beta-alumina electrolyte tube, alpha-alumina insulating ring and glass bonding agent ring inverted as they would be placed in the microwave oven in accordance with the principles of the present invention;
Figure 2 is a graph illustrating the processing temperature and processing time of the present method as compared with the conventional method utilizing a gas flame or electrical resistance heat source;
Figure 3 is a scanning electron microscope mi-crophotograph at 2Dx of a joint constructed in accordance with the present invention;
Figure 4 is a scanning electron microscope mi-crophotograph similar to Figure 3 showing a comparable joint constructed in accordance with conventional prac-tice; ', Figure 5 is an SI map of the seal showing thecontour of the:glass with high silicon content of the present joint of Figure 3;
Figure 6 is an 5I map similar to Figure 5 o~ the ,prior art joint of Figure,4;
Figure 7 is a scanning electron microscope and EDAX microphotograph sho~ing an SI line scan of a magni-tude of 500x of the present joint of Figure 3; and Fisure 8 is a microphotograph similar to Figure 7 of the prior art joint of Figure 4.
1~1D0~;77 Referring now more particularly to the drawings there is shown in Figure 1 two components of a sodium sul-fur battery cell, one a beta-alumina electrolyte tube,.
generally indicated at 10 and the other an insulating ring, generally indicated at 12, for the tube 10. The tube 10 is in the form of a cylinder body 14 having a dome 16 closing an end thereof. The insulating ring 1~ is an alpha alumina body forming an exterior flange for the electrolyte tube 10. The components are joined in accor-dance with the principles of the present invention and once joined are used in a sodium sulfur battery in accor-dance with the disclosure contained in U.S. Patent ~,207,386.
It will be noted that the electrolyte tube when embodied in the bat-tery cell is inverted from the position shown in Figure 1 so that the dome 14 is -at the lower end thereof and the flange is at the upper end thereof. It will be noted that for example in ~igure 1 of Patent 4,207,386 the electro-lyte tube is identified by the n~meral 2 and the flange is identified by the.numeral 12.
The insulating ring or flange 20 of the present invention includes an interior cylindrical surface 18 which, in the orientation shown in Figure 1 of the present .drawings,.extends upwardly from the lower surface of the ring 12. The cylindrical surface 18 intersects with a frusto-conical surface.20 which terminates at the upper surface of the insulating ring. The insulating ring 12 is assembled on the open end of the electrolyte tube 10 by engaging the interior surface 18 of the insulating ring with a portion of the exterior periphery of the cylinder 14 forming the major part of the tube 10. The frusto-con-ical surface 20 defines with the axially coextensive ex-terior surface of the cylinder 14 an annular recess 22 which is essentially wedge-shaped in cross-sectional con-figuration. Mounted within the recess 22, as shown in 131D06~77 Figure 1, is a bonding agent, such as glass. The g~ass utilized in the bonding agent is devoid of any additives particularly additives such as coupling agents or the like capable of being heated when s~bjected to microwave energy.
The glass bonding agent, as shown, is a solid body 24 having a solid form shape which is essentially an annular bead with a wedge shaped cross-sectional configur-ation corresponding with the wedge shaped cross-section of the recess 22 which receives the same.
In a~eordance with the principles of the present method, the assembled components as shown in ~igure 1 are then placed in an industrial type microwave oven. An ex-ample of a microwave oven which may be utilized is a Lit-ton*Model 1521 operating at 2.45 gHz with a power output of 700 watts. Preferably, the assembly as shown in Pigure 1 is first placed in an insulating enclosure, such as a closely dimensional ceramic tube which is transparent for microwaves and is heat resistant at the temperature of bonding. The insulatina enclosure is desirable, partic-ularly to reduce sodium loss when dealing with sodium sul-fur battery parts, although it may be dispensed with if desired. The assembly in the insulating enclosure was ex-posed to microwaves for a short period of time. Only a few minutes (e.g. 12 minutes) was required to heat the beta-alumina tube to the required temperature of approxi-mately 1100C. The glass body and the alpha-alumina were heated due primarily to thermal conduction from the beta-alumina and to some extent by convection as well. Only a short period of time was required to accomplish cooling ~e.g. 18 minutes). As a result of the glass melting and subsequent cooling a strong hermetic seal was formed.
The processing time within the microwave oven in acc~rdance with the principles of the present invention is illustrated graphically in ~igure 2 and it will be noted that in the scale shown the application temperature-time * Trade-mark ~3~
relationship represents a relatively high spike configura-tion. Also included on the graph of Figure 2 is the tem-perature time relationship when the same assembly as shown in Figure 1 is conventionally heated using a gas flame or electrical resistant heat source. As shown on the graph, more than four times more energy is utilized with the con-ventional gas flame or electrical resistance heat source than with the microwave energy in accordance with the principles of the present invention. Moreover, the dura-tion of the prior art treatment was reduced by more than a factor of 40 in practicing-the principles of the present invention.
By utilizing the procedures of the present in-vention a joint with superior properties is obtained com-pared to the joint made by conventional heating in a gas or electric furnace. The difference in the quality of the joint is attributed to the different kinetics of the reac-tion causing extensive diffuslon of glass into the alpha-alumina ceramics and resulting in a different microstruc-ture of the joint when microwave heating is applied.
Figure 3 illustrates a scanning electron micro-scope microphotograph at 20K of the joint produced in ac-cordance with the principles of the present invention and it will be noted that it is of comparable or better quality when compared with the conventional joint shown in Figure 4.
Figure 5 is a silicon map of the joint of the present invention such as shown in Figure 3 and it will be noted that the configuration of the glass in the joint differs from the configuration in the prior art joint shown in Figure ~ which has a distinct tail or a flow of glass beyond the recess.
~ inally, a comparison of the silicon line scan at a magnification of 500x is shown in Figure 7 of the joint constructed in accordance with the principles of the present invention. It is significant to note that ~300677 substantial penetration of silicon into the alpha-alumina is shown in the righthand portion of the figure. The com-parable penetration of the prior art joint is shown in Figure 8 and it will be noted that significantly less pen-etration of silicon into the alpha-alumina is indicated.
The difference in configuration as depicted in Figures 5 and 6 and the difference in the penetration as depicted in Figures 7 and 8 demonstrate a highly desirable joint has been produced by the present invention in comparison with prior art procedures.
It thus will be seen that the objects of this invention have been fully and effectively accomplished.
It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.
Claims (4)
1. A method of producing a joint between a body of beta-alumina and a body of alpha-alumina with a glass bonding agent devoid of coupling additives capable of being heated when subjected to microwave energy, wherein the glass bonding agent is applied in the form of a solid body to a surface of said beta-alumina body and a surface of said alpha-alumina body which comprises;
subjecting said beta-alumina body and said alpha-alumina body with said glass body engaged to said surfaces thereof to microwave energy from a microwave source so as to heat said beta-alumina body by microwave energy for a time period sufficient to enable the heat generated in said beta-alumina body to be conducted to said glass body and said alpha-alumina body and heat the glass body to a temperature above the glass deformation point, and allowing the bodies to cool to solidify the glass body in intimately penetrating relation to the surfaces of the beta-alumina and alpha-alumina engaged thereby so that the glass body forms a bond between the beta-alumina body and the alpha-alumina body characterized by a fusion of the glass within the engaged beta-alumina and alpha-alumina, the time period to which the bodies are subjected to microwave energy being not substantially longer than that required to heat the glass to said deformation point of the glass.
subjecting said beta-alumina body and said alpha-alumina body with said glass body engaged to said surfaces thereof to microwave energy from a microwave source so as to heat said beta-alumina body by microwave energy for a time period sufficient to enable the heat generated in said beta-alumina body to be conducted to said glass body and said alpha-alumina body and heat the glass body to a temperature above the glass deformation point, and allowing the bodies to cool to solidify the glass body in intimately penetrating relation to the surfaces of the beta-alumina and alpha-alumina engaged thereby so that the glass body forms a bond between the beta-alumina body and the alpha-alumina body characterized by a fusion of the glass within the engaged beta-alumina and alpha-alumina, the time period to which the bodies are subjected to microwave energy being not substantially longer than that required to heat the glass to said deformation point of the glass.
2. The method as defined in claim 1 comprising employing said beta-alumina body as a solid electrolyte of a sodium/sulphur battery cell in the form of a cylinder having a dome closing an end thereof and said alpha-alumina body is an exterior support for the solid electrolyte in the form of an annular flange having its interior periphery engaged with the exterior periphery of said cylinder at the end thereof opposite said dome.
3. The method as defined in claim 2 comprising employing said glass body in the form of annular bead of wedge shaped cross-section.
4. The method as defined in claim 3 comprising employing a flange having an interior periphery also including a frusto-conical surface defining with an axially coextensive portion of the exterior periphery of said cylinder a wedge shaped recess receiving the wedge shaped annular bead forming said glass body.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US020,354 | 1987-03-02 | ||
| US07/020,354 US4792348A (en) | 1987-03-02 | 1987-03-02 | Method of forming glass bonded joint of beta-alumina |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1300677C true CA1300677C (en) | 1992-05-12 |
Family
ID=21798170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000560372A Expired - Lifetime CA1300677C (en) | 1987-03-02 | 1988-03-02 | Method of forming glass bonded joint of beta-alumina and other ceramic and joint formed thereby |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4792348A (en) |
| AU (1) | AU1496388A (en) |
| CA (1) | CA1300677C (en) |
| WO (1) | WO1988006571A1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5196277A (en) * | 1990-10-25 | 1993-03-23 | Ngk Insulators, Ltd. | Sodium-sulfur cell and method of joining solid electrolyte tube and insulative ring |
| US6216492B1 (en) * | 1994-10-14 | 2001-04-17 | Heraeus Quarzglas Gmbh | Methods and apparatus for providing quartz glass connectors |
| WO1998046047A1 (en) * | 1997-04-10 | 1998-10-15 | Nucon Systems, Inc. | Process and apparatus for microwave joining thick-walled ceramic parts |
| US7494904B2 (en) | 2002-05-08 | 2009-02-24 | Btu International, Inc. | Plasma-assisted doping |
| US7432470B2 (en) | 2002-05-08 | 2008-10-07 | Btu International, Inc. | Surface cleaning and sterilization |
| JP2005524963A (en) | 2002-05-08 | 2005-08-18 | ダナ・コーポレーション | Plasma catalyst |
| US7638727B2 (en) | 2002-05-08 | 2009-12-29 | Btu International Inc. | Plasma-assisted heat treatment |
| US7497922B2 (en) | 2002-05-08 | 2009-03-03 | Btu International, Inc. | Plasma-assisted gas production |
| US7445817B2 (en) | 2002-05-08 | 2008-11-04 | Btu International Inc. | Plasma-assisted formation of carbon structures |
| US7498066B2 (en) | 2002-05-08 | 2009-03-03 | Btu International Inc. | Plasma-assisted enhanced coating |
| US7560657B2 (en) | 2002-05-08 | 2009-07-14 | Btu International Inc. | Plasma-assisted processing in a manufacturing line |
| US7465362B2 (en) | 2002-05-08 | 2008-12-16 | Btu International, Inc. | Plasma-assisted nitrogen surface-treatment |
| US7189940B2 (en) | 2002-12-04 | 2007-03-13 | Btu International Inc. | Plasma-assisted melting |
| CN103123984B (en) * | 2012-12-12 | 2014-12-10 | 上海电气钠硫储能技术有限公司 | Glass sealing process of sodium-sulfur battery |
| CN118754698A (en) * | 2024-07-26 | 2024-10-11 | 长春工业大学 | A two-step method for connecting alumina ceramics based on the principle of alumina powder solder sintering and glass infiltration |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4066427A (en) * | 1974-05-20 | 1978-01-03 | Tokyo Shibaura Electric Co., Ltd. | Bonding method using a soldering glass |
| FR2318841A1 (en) * | 1975-07-25 | 1977-02-18 | Comp Generale Electricite | BONDING PROCESS BETWEEN PARTS IN BETA ALKALINE AND ALUMINA ALPHA |
| CA1091025A (en) * | 1977-11-30 | 1980-12-09 | John A. Topping | Plug seals: glass composition, method and apparatus |
| DE2819583C2 (en) * | 1978-05-05 | 1983-01-20 | Brown, Boveri & Cie Ag, 6800 Mannheim | Electrochemical storage cell |
| US4529857A (en) * | 1983-10-04 | 1985-07-16 | The United States Of America As Represented By The United States Department Of Energy | Ceramic-glass-ceramic seal by microwave heating |
| US4529856A (en) * | 1983-10-04 | 1985-07-16 | The United States Of America As Represented By The United States Department Of Energy | Ceramic-glass-metal seal by microwave heating |
| US4606748A (en) * | 1984-10-10 | 1986-08-19 | The United States Of America As Represented By The Department Of Energy | Method for producing ceramic-glass-ceramic seals by microwave heating |
| JPS61138473A (en) * | 1984-12-07 | 1986-06-25 | Yuasa Battery Co Ltd | Sodium-sulfur cell and manufacture thereof |
| JPS61190869A (en) * | 1985-02-19 | 1986-08-25 | Yuasa Battery Co Ltd | Sodium-sulfur battery |
| US4661424A (en) * | 1985-10-04 | 1987-04-28 | Yuasa Battery Co. | Sodium-sulfur storage battery |
-
1987
- 1987-03-02 US US07/020,354 patent/US4792348A/en not_active Expired - Fee Related
-
1988
- 1988-03-02 CA CA000560372A patent/CA1300677C/en not_active Expired - Lifetime
- 1988-03-02 WO PCT/US1988/000548 patent/WO1988006571A1/en not_active Ceased
- 1988-03-02 AU AU14963/88A patent/AU1496388A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US4792348A (en) | 1988-12-20 |
| WO1988006571A1 (en) | 1988-09-07 |
| AU1496388A (en) | 1988-09-26 |
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