GB2272433A - Termination of ceramic capacitors - Google Patents
Termination of ceramic capacitors Download PDFInfo
- Publication number
- GB2272433A GB2272433A GB9223643A GB9223643A GB2272433A GB 2272433 A GB2272433 A GB 2272433A GB 9223643 A GB9223643 A GB 9223643A GB 9223643 A GB9223643 A GB 9223643A GB 2272433 A GB2272433 A GB 2272433A
- Authority
- GB
- United Kingdom
- Prior art keywords
- glass
- layers
- porous
- block
- metal oxide
- 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.)
- Withdrawn
Links
- 239000003985 ceramic capacitor Substances 0.000 title claims abstract description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 61
- 239000002184 metal Substances 0.000 claims abstract description 61
- 239000000919 ceramic Substances 0.000 claims abstract description 52
- 238000000034 method Methods 0.000 claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 21
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 20
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 20
- 239000003870 refractory metal Substances 0.000 claims abstract description 19
- 239000005388 borosilicate glass Substances 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 16
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims abstract description 14
- 238000005470 impregnation Methods 0.000 claims abstract description 12
- 239000005373 porous glass Substances 0.000 claims abstract description 10
- 238000009713 electroplating Methods 0.000 claims abstract description 7
- 238000010304 firing Methods 0.000 claims abstract description 4
- 239000011521 glass Substances 0.000 claims description 28
- 239000010408 film Substances 0.000 claims description 24
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000011148 porous material Substances 0.000 claims description 8
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical group O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 7
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical group [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 6
- 230000009477 glass transition Effects 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 239000000725 suspension Substances 0.000 claims description 6
- 229910010293 ceramic material Inorganic materials 0.000 claims description 4
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 3
- 229910052593 corundum Inorganic materials 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 3
- 229910052747 lanthanoid Inorganic materials 0.000 claims description 3
- 150000002602 lanthanoids Chemical class 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000010409 thin film Substances 0.000 claims description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000006194 liquid suspension Substances 0.000 claims description 2
- 238000005245 sintering Methods 0.000 claims description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims 8
- 230000004927 fusion Effects 0.000 claims 1
- 238000003825 pressing Methods 0.000 claims 1
- 239000010410 layer Substances 0.000 description 51
- 230000015572 biosynthetic process Effects 0.000 description 8
- 239000003990 capacitor Substances 0.000 description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 239000006060 molten glass Substances 0.000 description 5
- 238000005488 sandblasting Methods 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229920000896 Ethulose Polymers 0.000 description 2
- 239000001859 Ethyl hydroxyethyl cellulose Substances 0.000 description 2
- 229910000978 Pb alloy Inorganic materials 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 235000019326 ethyl hydroxyethyl cellulose Nutrition 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- -1 preferably organic Substances 0.000 description 2
- 229940043230 sarcosine Drugs 0.000 description 2
- VXQBJTKSVGFQOL-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethyl acetate Chemical compound CCCCOCCOCCOC(C)=O VXQBJTKSVGFQOL-UHFFFAOYSA-N 0.000 description 1
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 1
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- WUOACPNHFRMFPN-UHFFFAOYSA-N alpha-terpineol Chemical compound CC1=CCC(C(C)(C)O)CC1 WUOACPNHFRMFPN-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- SQIFACVGCPWBQZ-UHFFFAOYSA-N delta-terpineol Natural products CC(C)(O)C1CCC(=C)CC1 SQIFACVGCPWBQZ-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000007499 fusion processing Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 235000012054 meals Nutrition 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 150000004702 methyl esters Chemical class 0.000 description 1
- SWELZOZIOHGSPA-UHFFFAOYSA-N palladium silver Chemical compound [Pd].[Ag] SWELZOZIOHGSPA-UHFFFAOYSA-N 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000010665 pine oil Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920000205 poly(isobutyl methacrylate) Polymers 0.000 description 1
- 238000007761 roller coating Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229940116411 terpineol Drugs 0.000 description 1
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/228—Terminals
- H01G4/232—Terminals electrically connecting two or more layers of a stacked or rolled capacitor
- H01G4/2325—Terminals electrically connecting two or more layers of a stacked or rolled capacitor characterised by the material of the terminals
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C14/00—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix
- C03C14/004—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix the non-glass component being in the form of particles or flakes
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
- C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
- C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
- C03C8/16—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions with vehicle or suspending agents, e.g. slip
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
- C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
- C03C8/20—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions containing titanium compounds; containing zirconium compounds
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C2214/00—Nature of the non-vitreous component
- C03C2214/04—Particles; Flakes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Power Engineering (AREA)
- Ceramic Engineering (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Ceramic Capacitors (AREA)
Abstract
Electrically conductive terminals are provided on the opposite faces of a multi-layer ceramic capacitor by the technique of applying to the opposite faces of a fired or un-fired ceramic block of alternating porous and non-porous ceramic layers, a borosilicate glass frit containing a refractory metal oxide and optionally particles of a metal carbonate, firing the coated block to fuse the borosilicate glass frit and form opposing terminal layers of a porous glass composition on opposite faces of the ceramic block, and impregnating the block, through those porous glass terminal layers with a molten metal, e.g. by vacuum impregnation. If necessary, after impregnation, additional electrode layers can be deposited on the terminal faces of the block, e.g. by electroplating.
Description
TERMINATION OF CERAMIC CAPACITORS
This invention relates to the termination of multi-layer ceramic capacitors (MLCs), that is to say the formation of the electrically conductive terminal layers on the opposite faces of the ceramic block which forms the MLC and each in electrical contact with one set of the inter-digitating electrically conductive layers formed within the ceramic block and which act as the capacitor plates of the MLC.
Such capacitors are disclosed for example in US Patent
Specification Nos. 3679950 and 4030004 and in GB-A-2162371.
Various methods have been proposed and used in the manufacture of such MLCs, a common technique, described in US Patent 4030004 involving the steps of forming a green ceramic compact consisting of alternating layers of green ceramic material, alternative layers containing a fugitive binder, which when the green ceramic is fired, is either driven off or decomposed or a combination of the two to leave behind a ceramic block of alternating porous and non-porous layers. Those porous layers are so disposed within the block that they form two sets of interdigitating porous layers which extend inwardly from the opposite faces of the block but which stop short of the opposite end face.
Those porous layers are then injected with a molten metal which solidifies therein to provide the two sets of parallel capacitor plates extending substantially across the width of the block, but stopping short of the opposite face. One technique of injecting the molten metal into those porous layers described in US Patent 4030004 involves immersing the fired ceramic block in a bath of molten metal, applying a vacuum to evacuate the porous layers of the ceramic block followed by the application of pressure to force the molten metal into the pores of the evacuated porous layers.
Following the injection of the molten metal and the solidification thereof in the porous layers of the ceramic block, electrically conductive layers or films are applied to the opposite faces of the block to form the electrically conductive terminal layers each in electrical contact with a different one of the two sets of metal impregnated porous layers which now form the two sets of capacitor plates set in the ceramic block and separated by alternating dielectric layers of non-porous ceramic material.
It is in the application of those terminal layers that most problems arise in the manufacture of MLCs by the above techniques, those problems arising either from molten metal running back out of the porous layers following the injection process and prior to the formation of the terminal electrodes or from shrinkage and contraction of the injected metal upon cooling away from the end face making it difficult to achieve satisfactory electrical contact between the terminal electrode and the impregnating metal in the metal containing electrode layers of the capacitor.
Various methods have been proposed and/or used for the termination of such capacitors including the application of a porous ceramic or glass film to the opposite faces of the ceramic block prior to the injection process so that the molten metal is injected into the porous layers of the sintered ceramic block through that porous layer, that layer either being removed after the impregnation stcp, for example, by sand blasting prior to actual formation of the termination, or leaving those layers in place to be impregnated by the molten metal at the same time as the impregnation of the molten metal into the porous layers of the ceramic block, those impregnated surface layers then serving as the terminal electrode layers on the opposite faces of the block.Both techniques are disclosed in US Patent 4030004 but with the primary emphasis on the former, i.e. injection of the impregnating metal through a porous sintered film on the opposite faces of the block, followed by the removal of those films by sandblasting prior to formation of the terminal electrode layers on those faces (Examples 8, 9 and 10). An alternative procedure disclosed in US Patent 4030004 is to apply a thin porous film of a high melting point metal or metal alloy e.g. palladium-silver or palladium-gold, to the opposite faces of the block prior to impregnation, and impregnating the block through those porous metallic films, those films themselves then forming the terminal electrodes of the capacitor.
In GB-A-2162371 that latter technique is modified in that the porous metal films on the opposite end faces of the ceramic block are of a metal, e.g. chromium or nickel, that is wetted by the impregnating metal, which is usually lead or lead alloy. Allegedly the use of a metal, which is wetted by the impregnating metal, to form the porous metal films on the faces of the ceramic block and through which the molten metal is impregnated into the block, eliminates or reduces the amount of molten metal which runs back out of the porous layers at the end of the injection process. In US Patent 4030004, run out the injected metal is prevented or eliminated by injecting the molten metal through a porous glass or ceramic layer on the end faces of the block which then has to be removed by sand-blasting before the termination is applied.In the alternative, it is suggested in the US Patent that the glass or ceramic layer can be left in place and the termination applied over that layer, but no enabling disclosure is given.
In accordance with the present invention an improved technique and improved composition has been developed for use in the termination of such multi-layer ceramic capacitors.
This technique comprises applying to the opposite faces of the ceramic block, either in the fired condition and comprising the alternate porous and non-porous layers, or to the unfired green ceramic block comprising the alternate layers of pore-forming and non-poreforming green ceramic material, a thin film of a glass frit composition comprising particles of a borosilicate glass having a glass transition temperature below about 9000C in admixture with particles of a refractory metal oxide or mixture of refractory metal oxides fusible with the borosilicate glass and/or with particles of a group I or group
IIa metal carbonate, suspended as a paste in a liquid, preferably organic, suspension medium, heating the ceramic block to a temperature above the glass transition temperature of the borosilicate glass particles, and in the case of an unfired ceramic block, sufficient also to effect the sintering of the unfired ceramic, allowing the block to cool to provide a fired ceramic block of alternate porous and nonporous layers coated on its opposite faces by a thin, porous fused film of borosilicate glass. That block is then impregnated with the molten metal in the conventional manner by immersing the block in a bath of molten metal, evacuating the porous layers of the ceramic block, and allowing or causing the molten metal to impregnate the porous layers of the ceramic block, such impregnation taking place through the pores of the porous borosilicate glass film fused onto the opposite faces of the block, the impregnating meal impregnating not only the porous layers of the ceramic block but also the porous borosilicate glass films on the opposite faces of the block.Following that impregnation the impregnated block is removed from the molten metal bath, cooled to solidify the metal impregnated into the porous layers of the ceramic block and into the pores of the two borosilicate glass films, and treated, e.g. by electroplating, to deposit a thin film of electrode material directly onto the surface of the two borosilicate glass films in electrical contact with the impregnating metal.
Compared with Example 10 of US-A-4030004, the characterising features of the above process are: 1) the use of a lower melting point glass frit, which is heated to
above its melting point to fuse the glass termination layer onto
the opposite faces of the ceramic block; Example 10 uses a
borosilicate glass frit melting at about 10800C and which is
heated to 7600C sufficient to burn off the vehicle (the pine oil)
and the pore forming agent (the acrylic resin) but insufficient
to fuse the glass frit; 2) the use of either a refractory metal oxide or a mixture of such
oxides or a metal carbonate or both in place of the
fugitive pore forming agent used in US-A-4030004, the effect of
the refractory metal oxide(s) when used being to increase the
viscosity of the molten glass film formed on the faces of the
ceramic block as a result of the refractory metal oxide(s)
dissolving in the molten glass film, that increase in viscosity
resulting in a glass termination layer of uniform porosity on the
face of the ceramic block, that uniform porosity, in the case of
metal carbonate additions, further being assisted by the
evolution of C02 and CO during the fusion process, where metal
carbonate alone is used, pore formation is obtained simply as a
result of that CO and C02 evolution without any material change
in the viscosity of the molten glass as occurs when a refractory
metal oxide is used; and 3) the formation of the electrically conductive terminals on the
block, following impregnation of the block through the porous
glass termination layers with the molten metal which penetrates
the alternating porous layers of the block to form the spaced
electrically conductive layers or plates of the capacitor,
directly onto the glass termination layers, e.g. by
electroplating, without prior sand-blasting to remove those
layers as taught in Example 10 of US-A-4030004.
As indicated above, the process of the invention utilises, in the formation of porous glass termination layers on the opposite faces of the ceramic block, prior to impregnation of the block with the molten metal, and the subsequent formation of the electrically conductive terminal layers directly on to those porous terminated layers and into electrical contact with the impregnating metal in those layers, a glass paste containing:
1. finely divided particles of a relatively low melting point
borosilicate glass, i.e. having a glass transition
temperature below about 9000;
2. a liquid vehicle for the glass particles, that liquid
vehicle preferably being organic;
3. finely divided particles of one or more refractory metal
oxide(s) and/or a group I or IIa metal carbonate.
Usually, but not necessarily, the paste will contain a dispersing agent e.g. a surfactant to assist in the uniform dispersion of the solid particulate components of the paste into the liquid suspension medium.
Relative proportions, by wt. will usually be:
% by wt.
Component General Range Preferred Range 1. borosilicate 15 - 30 20 - 25 glass frit 2. refractory metal oxide and/or 25 - 40 30 - 35 alkali alkali metal carbonate 3. rare earth metal oxide e.g. cerium 0 - 15 1 5 - 10 (IV) oxide 4. dispersing agent O - 5 5 0.5 - 1.5 5. liquid vehicle q.s. 100% q.s. 100% Average particle size of the particulate components of the paste will usually be in the range 0.1 to 25.Opin preferably 0.2 to 5. m.
As the refractory metal oxide there may be used one or more of the following: Al203, ZerO2, TiO2, preferably in admixture with an oxide of a lanthanide metal and preferably cerium (IV) oxide.
As the metal carbonate, calcium carbonate is preferred.
As indicated, the suspension medium is organic and is preferably a cellulosic solvent such as ethyl hydroxyethyl cellulose dissolved in terpinegol.
Suitable dispersants agents include: n-sarcosine and leithin.
The glass-containing paste may be applied to the opposite faces of the cured or uneven ceramic block by any suitable method, e.g.
dipping or roller coating and will usually be applied to a thickness of 10 to 40 m, preferably 23 to 25 m.
A typical glass paste formulation for use in the process of the invention is as follows:
Inorganic components %by wt Organic components % bv wt.
PbO-B203-SiOZ 21.70 Isobutyl methacrylate
polymer 1.53 Awl203 27.60 Terpineol 20.94
CeO2 6.20 Hydrogenated methyl
esters of rosin 3.50
TiO2 6.20 Dioctyl phthalate 2.56
Co pigment 0.30 n-sarcosine 1.25
62.00
Ethyl hydroxyethyl
cellulose 3.22
2-(2-Butoxy ethoxy)
ethyl acetate 5.00
38.00
Following application of the paste, the ceramic block is fired at a temperature above the m.p. of the glass frit sufficient to fuse the glass frit onto the terminal faces of the ceramic block with concomitant dissolution of the refractory metal oxide(s) into the molten glass fibre and/or decomposition of the metal carbonate and consequent dissolution of the metal oxide into the molten glass and release of carbon dioxide or carbon monoxide.Where the glass paste is applied to the terminal faces of an uncured ceramic block, the firing temperature will be sufficient to sinter the ceramic block and simultaneously fuse the glass termination film on to the opposite faces of the sintered block.
Following firing, the ceramic block with the applied glass termination films is allowed to cool, and then impregnated with a molten metal or metal alloy, usually lead or lead alloy in a conventional manner such as taught, for example, in either US-A-4030004 or GB-A-2162371. Since that impregnation process is entirely conventional it need not be described herein in any further detail.
Likewise, following impregnation of the ceramic block through the porous glass termination films, the deposition of the electrically conductive layers directly on to the surface of those films in electrical contact with the impregnating metal can be carried out in any suitable manner, such as by electroplating, and again need not be deposited here in any more detail, suitable electroplating bath compositions for use in the electroplating process and the temperature and other conditions, e.g. current density, applied during the plating process all being conventional and well within the ability of the person skilled in the art to determine for himself. A wide variety of electrically conductive metals and alloys may be used for that purpose, with nickel and nickel based alloys being preferred.
Claims (15)
1. A method for the manufacture and termination of multi-layer ceramic capacitors, which comprises applying to the opposite faces of the ceramic block, either in the fired condition and comprising the alternate porous and non-porous layers, or to the unfired green ceramic block comprising the alternate layers of pore-forming and non-poreforming green ceramic material, a thin film of a glass frit composition comprising particles of a borosilicate glass having a glass transition temperature below about 9000C in admixture with particles of a refractory metal oxide or two or more such oxides fusible with the borosilicate glass and/or with particles of a group I or group IIa metal carbonate, suspended as a paste in a liquid, suspension medium, heating the ceramic block to a temperature above the glass transition temperature of the borosilicate glass particles, and in the case of an unfired ceramic block, sufficient also to effect the sintering of the unfired ceramic, allowing the block to cool to provide a fired ceramic block of alternate porous and non-porous layers coated on its opposite faces by a thin, porous fused film of borosilicate glass, introducing a molten metal or alloy into the alternating porous layers of the ceramic block through the porous glass termination films formed on the opposite faces of the block, allowing that molten metal to solidify in the alternating porous layers of the ceramic block and in the pores of the porous glass termination films, and applying an electrically conductive electrode layer directly on to the metal impregnated glass termination layers and into electrical contact with the impregnating metal.
2. A method according to claim 1, wherein the glass frit is applied to the opposite faces of the cured or uncured ceramic block in suspension in an organic liquid as the suspension medium.
3. A method according to claim 1 or 2, wherein the glass paste comprises finely divided particles of a refractory metal oxide selected from one or more of Al20Z, ZrO2, TiO2 and rare earth metal oxides.
4. A method according to claim 3, wherein the paste contains as said refractory metal oxide a mixture containing finely divided particles of i) one or more of Al203, ZrO2 and TiO2 and b) a rare earth metal oxide of the lanthanide series.
5. A method according to claim 6, wherein the rare earth metal oxide is cerium (IV) oxide.
6. A method according to any one of the preceding claims, wherein the glass paste comprises particles of both a refractory metal oxide and a Group I or Group IIa metal carbonate.
7. A method according to claim 6, where said metal carbonate is calcium carbonate.
8. A method according to any one of claim I to 7, wherein following firing and fusion of the porous glass termination films on the opposite faces of the ceramic block, the metal impregnation process is affected by immersing the block in a bath of molten metal, applying a vacuum to the block when so immersed thereby to evacuate the alternating porous layers of the block and the porous glass termination layers, and subsequently applying pressure to impregnate the molten metal into the evacuated pores of the alternating layers of the ceramic block and of the said glass terminated layers.
9. A method according to any one of claims 1 to 8, wherein the electrode layers are applied directly to the metal impregnated glass termination layers by electroplating.
10. A glass paste composition for use in the method of claim 1, comprising a suspension of finely divided particles of a borosilicate glass having a glass transition temperature below about 9000C suspended in a liquid suspension medium and containing in addition finely divided particles of a refractory metal oxide or two or more such oxides and/or a Group I or Group IIa metal carbonate.
11. A paste composition according to claim 10, wherein the glass paste comprises finely divided particles of a refractory metal oxide selected from one or more of Al203, ZrO2, TiO2, and rare earth metal oxides.
12. A paste composition according to claim 11, wherein the paste contains as said refractory metal oxide mixture of finely divided particles of i) one or more of At203, ZrO2 and TiO2 and ii) a rare earth metal oxide of the lanthanide series.
13. A paste composition according to claim 12, wherein the rare earth metal oxide is cerium (IV) oxide.
14. A paste composition according to any one of claims 10 to 13, wherein the glass paste comprises particles of both a refractory metal oxide and a Group I or Group IIa metal carbonate.
15. A paste composition according to claim 14, wherein the metal carbonate is calcium carbonate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9223643A GB2272433A (en) | 1992-11-11 | 1992-11-11 | Termination of ceramic capacitors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9223643A GB2272433A (en) | 1992-11-11 | 1992-11-11 | Termination of ceramic capacitors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9223643D0 GB9223643D0 (en) | 1992-12-23 |
| GB2272433A true GB2272433A (en) | 1994-05-18 |
Family
ID=10724915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9223643A Withdrawn GB2272433A (en) | 1992-11-11 | 1992-11-11 | Termination of ceramic capacitors |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2272433A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2336244A (en) * | 1998-04-07 | 1999-10-13 | Murata Manufacturing Co | Ceramic electronic component with terminal electrodes having a three layer structure |
| GB2447321A (en) * | 2007-01-31 | 2008-09-10 | Avx Corp | Termination Bonding of Electrical Components |
| US7832618B2 (en) | 2007-01-31 | 2010-11-16 | Avx Corporation | Termination bonding |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1392393A (en) * | 1971-07-02 | 1975-04-30 | Owens Illinois Inc | Liquid carrier vehicles and pastes made therefrom for use in micro-electronic printing |
| GB1548117A (en) * | 1976-12-27 | 1979-07-04 | Philips Nv | Dielectric compositions |
| EP0146119A2 (en) * | 1983-12-19 | 1985-06-26 | E.I. Du Pont De Nemours And Company | Borosilicate glass compositions |
| EP0253342A1 (en) * | 1986-07-15 | 1988-01-20 | E.I. Du Pont De Nemours And Company | Glass ceramic dielectric compositions |
-
1992
- 1992-11-11 GB GB9223643A patent/GB2272433A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1392393A (en) * | 1971-07-02 | 1975-04-30 | Owens Illinois Inc | Liquid carrier vehicles and pastes made therefrom for use in micro-electronic printing |
| GB1548117A (en) * | 1976-12-27 | 1979-07-04 | Philips Nv | Dielectric compositions |
| EP0146119A2 (en) * | 1983-12-19 | 1985-06-26 | E.I. Du Pont De Nemours And Company | Borosilicate glass compositions |
| EP0253342A1 (en) * | 1986-07-15 | 1988-01-20 | E.I. Du Pont De Nemours And Company | Glass ceramic dielectric compositions |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2336244A (en) * | 1998-04-07 | 1999-10-13 | Murata Manufacturing Co | Ceramic electronic component with terminal electrodes having a three layer structure |
| GB2336244B (en) * | 1998-04-07 | 2001-02-14 | Murata Manufacturing Co | Ceramic electronic component and method for producing the same |
| US6219220B1 (en) | 1998-04-07 | 2001-04-17 | Murata Manufacturing Co., Ltd. | Ceramic electronic component having terminal electrode that includes a second porous layer |
| GB2447321A (en) * | 2007-01-31 | 2008-09-10 | Avx Corp | Termination Bonding of Electrical Components |
| US7832618B2 (en) | 2007-01-31 | 2010-11-16 | Avx Corporation | Termination bonding |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9223643D0 (en) | 1992-12-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4030004A (en) | Dielectric ceramic matrices with end barriers | |
| US3965552A (en) | Process for forming internal conductors and electrodes | |
| Powers | The electrophoretic forming of beta‐alumina ceramic | |
| US5495386A (en) | Electrical components, such as capacitors, and methods for their manufacture | |
| EP1383940B1 (en) | Functional ceramic layers based on a support layer produced with crystalline nanoparticles | |
| JPS63260197A (en) | Manufacture of multilayer circuit structure | |
| JP2008503049A5 (en) | ||
| CN114512345A (en) | High specific volume porous electrode foil and preparation method thereof | |
| GB2272433A (en) | Termination of ceramic capacitors | |
| EP3389064A1 (en) | Method for manufacturing aluminum electrolytic capacitor electrode | |
| JPH0687402B2 (en) | Getter device manufacturing method | |
| DE2155217A1 (en) | Electrostatic photocopying material prodn - by plasma spraying dielectric and/or photoconductive layer | |
| US5254360A (en) | Process for producing ceramic capacitors with thinner electrodes | |
| US3850733A (en) | Method of forming foundry moulds | |
| WO2009115317A1 (en) | A method for producing a multilayer structure | |
| EP0220252B1 (en) | Cr2o3 protective coating and process for its manufacture | |
| DE825195C (en) | Process for producing rough metal layers | |
| JP3899503B2 (en) | Nickel powder with excellent oxidation resistance and method for producing the same | |
| RU2046157C1 (en) | Method for microarc oxidation of valve metals | |
| JPH0610112A (en) | Method for strengthening inorganic coating film | |
| JP3166333B2 (en) | Ceramic coating method | |
| JP2511236B2 (en) | Sealing method for thermal spray coating and coating composite | |
| JPH0286665A (en) | Primer of conductive coating material for plating and plating by using same | |
| JPS6353252B2 (en) | ||
| JPS6042287A (en) | Porous ceramic partial minuting process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |