GB2026773A - Process for the manufacture of tantalum solid electrolyte capacitors - Google Patents
Process for the manufacture of tantalum solid electrolyte capacitors Download PDFInfo
- Publication number
- GB2026773A GB2026773A GB7921295A GB7921295A GB2026773A GB 2026773 A GB2026773 A GB 2026773A GB 7921295 A GB7921295 A GB 7921295A GB 7921295 A GB7921295 A GB 7921295A GB 2026773 A GB2026773 A GB 2026773A
- Authority
- GB
- United Kingdom
- Prior art keywords
- capacitors
- ageing
- voltage
- anodes
- bed
- 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.)
- Granted
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- 239000003990 capacitor Substances 0.000 title claims abstract description 59
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 title claims abstract description 11
- 229910052715 tantalum Inorganic materials 0.000 title claims abstract description 10
- 239000007784 solid electrolyte Substances 0.000 title claims abstract description 8
- 238000000034 method Methods 0.000 title claims description 16
- 230000032683 aging Effects 0.000 claims abstract description 61
- 239000004065 semiconductor Substances 0.000 claims abstract description 12
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 claims description 12
- 238000007598 dipping method Methods 0.000 abstract 1
- 230000002950 deficient Effects 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 230000001681 protective effect Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000035876 healing Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000007743 anodising Methods 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000011179 visual inspection Methods 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
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/0029—Processes of manufacture
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Abstract
The invention is directed towards reducing the cost of the accelerated ageing operation in the course of manufacture of tantalum solid- electrolyte capacitors. The ageing is carried out by dipping the capacitors into a bed of pulverous semiconducting material connected to the negative terminal of a stabilised- voltage source, of which the positive pole is connected to the anodes of the capacitors. The voltage is maintained between 1.2 and 1.8 times the rated voltage of the capacitor and the temperature is maintained between 25 DEG C and 180 DEG C for a minimum period of two hours.
Description
SPECIFICATION
Process for the manufacture of tantalum solid-electrolyte capacitors
Ageing tantalum solid-electrolyte capacitors is a heavy industrial problem, because this step, which is necessary for the production of high performance capacitors to which users have gradually become accustomed, accounts for an appreciable proportion of the production cost. Despite the accelerated ageing processes of current practice now a days, this step is still lengthy and a duration of about twenty hours is usually considered necessary and this involves manipulations which give rise to heavy expenditure both from the viewpoint of labour and from the viewpoint of the necessary capital outlay. It is known to carry out an accelerated ageing by maintaining the capacitor under a direct voltage, while bringing it to a temperature close to or above the maximum temperature at which it is to operate.An example of such process is described in British Patent 1,199,058 filed by International
Standard Electric Corporation on the 9th November, 1967, which describes an accelerated ageing under voltage performed during the tinning step. United States Patent 3,653,1 19 assigned to Sprague and applied for on the 28th December, 1967, describes an accelerated ageing under voltage which is to take place after the anode formation by immersing them in a fused salt bath, the melting temperature of which is between 2500C and 4000C. The applied voltage is about 0.1 5 times the anodizing voltage, which remains below 0.5 times the rated voltage.One advantage of the latter process resides in that it is a batch process and it allows automatic protection of the anodes in the course of the treatment even if one of them proves to be defective (even short-circuited) as a result of the formation of a gaseous envelope around the defective part, which electrically insulates it from the molten bath. However such an ageing process is so complex that it is of very little use in production.
At present, it is usual to proceed with ageing of the anodes as follows: the anodes, after formation, are mounted on holders, in series with individual protective resistors, and then subjected to the following treatment: 4 hours at ambient temperature at 1.4 times the rated voltage with a series resistance of 10 kilohms -15 hours at 850C at rated voltage with a series resistance of 1 kilohm, that is to say, a total treatment duration of 19 hours, preceded by mounting of the anodes, taken one by one, on a carrier bar and changing over the protective resistors between the two operating stages. It is readily apparent from the foregoing brief description of the process that the ageing operation is costly both in capital outlay and in labour.
The present invention has essentially for its object to provide a process for accelerated ageing under voltage which utilises the anodes mounted on the carrier bar, used for the oxidizing stage, without requiring any particular manipulation in the ageing stage, the duration of which is reduced in a ratio of about 10 in relation to the previously described process and which affords automatic protection of the neighbouring capacitors in the event of a defective anode without the need of any limiting resistor. It further has the advantage that it permits, in the course of the ageing, a self-healing of certain defective capacitors by reoxidation of the tantalum at the weak points.
Accelerated ageing according to the invention is effected by immersing the anodes mounted on a carrier bar used in the formation step in a bed of pulverous semiconducting material, the anodes being brought to a temperature between 250C and 1 800C while being maintained at a direct voltage between 1.2 and 1.8 times the rated voltage of the capacitor for a period which is not less than 2 hours.
In a preferred variant of the invention, the semiconductor employed is an oxide and more particularly a metallic oxide exhibiting different possible degrees of oxidation.
The immersion of the anode carrier bars, as already mounted for the purpose of nitrate impregnation and formation, in a bed of pulverous semiconductor, makes it possible to dispense with the limiting resistors to be connected in series with each anode in the case of ageing under voltage. The bed, which is contained in a metailic receptacle connected to one of the terminals of the voltage source, of which the other terminal (the positive terminal) is connected to the carrier bar, performs the function of a limiting resistance for each of the anodes taken individually. Since the resistivity of most semiconductors decreases rapidiy when the temperature increases, the protective resistance afforded by the bed therefore automatically takes a value depending upon the temperature.The value of the resistance in series with each anode depends upon the quantity of oxide powder and its grain size repartition.
The preferred use of a semiconductor of the oxide type in the ageing treatment according to the invention results from the fact that some of them are capable of changing spontaneously in their degree of oxidation as a function of the temperature with liberation of oxygen when the temperature rises. This is the case more particularly with manganese dioxide which is reduced in accordance with the reaction 2Mn02Mn203+1/2 2 at 5800C. Emission of oxygen is detected from 3000C upwards. This reaction is advantageous in the present case for two reasons: the resistivity of MnO2 is relatively low ohm-cm), while the resistivity of My203 is much higher (104 to 105 ohm-cm) and the heating produces an emission of particularly reactive nascent oxygen.The first property results in the automatic switching off of a defective anode, because in the event of a short-circuit (or near it) of one of the anodes, the high current which flows through the bed in the neighbourhood thereof creates a local temperature rise and a rapid decrease in the resistivity of the bed due to resistivity change of the dioxide; the phenomenon quickens and the temperature rise rapidly becomes sufficient to initiate the aforesaid reaction. The dioxide is therefore reduced in the neighbourhood of the defective part which is surrounded by highly resistive material and is insulated from the neighbouring parts. The simultaneous emission of oxygen permits, in some cases, a reoxidation of the defective anode analogous to a second formation.
The main advantages of the invention can therefore be summarised as follows: -reduction of the necessary capital outlay for equipment -reduction of the duration of the ageing stage in a ratio of about 1 to 10 -avoidance of the handling of the anodes before the ageing stage -protection of the anodes close to a defective anode -self healing of certain defective anodes during the ageing treatment.
The invention will be more readily understood from the following description and from the accompanying figures which are given by way of non limiting illustration and in which:
Figure 1 is a diagram of the ageing arrangement according to the invention, -Figure 2 is a diagram of the ageing arrangement according to the invention, -Figure 3 is a diagram of a batch of capacitors undergoing ageing, -Figure 4 contains three distributions of capacitors as a function of the leakage current for comparing the ageing according to the prior art with that according to the invention; and Figure 5 contains four distributions of capacitors as a function of the leakage current permitting comparison of the influence on the ageing on a bed of different voltages and temperatures.
The attached Table 1 is a table summarising the results of the measurements given by tests corresponding to the distributions of Figure 5.
Figure 1 illustrates the stages of manufacture of capacitors according to the prior art (Figure 1 A) and according to the invention (Figure 1 B) respectively, from which the advantages of the latter will be readily appreciated.
There are successively illustrated the following common stages to both prior art and the invention (stage 1) manufacture of the anode by the technique of powder metallurgy. The sintered anodes are thereafter (stage 2) mounted on conductive bars or strips by soldering of the anode connection.
Sometimes, the anodes are pre-oxidised in bulk, as described, for example, in the British Patent 1,542,226 filed by the Applicants on the 3rd January, 1 978, for: "Improvement in the surface treatment of the anodes of tantalum capacitors" before mounting. The bars are mounted on frames or racks which constitute the production units for the subsequent stages of production. Depending upon the dimensions of the anodes, a frame supports between several hundred and several thousand anodes.
The subsequent operations are concerned with the oxidation, the impregnation with manganese nitrate and the pyrolysis of the latter (stage 3), which are repeated a number of times, followed by the forming of the cathode (stage 4) by graphiting and silvering, optionally followed by tinning of the silver coating.
These four stages are common to the prior art and to the present invention.
In the case of metal encapsulated capacitors, the bars are thereafter removed from the frames and the capacitors are separated from the bars (stage 5) in order to be individually encapsulated (stage 6) and then individually mounted in the ageing rack (stage 7) comprising the individual resistors for the protection of each capacitor. The ageing is usually carried out at two different temperatures and lasts twenty hours as stated in the foregoing. The ageing rack necessitating the change-over of the individual protective resistors is a relatively complex apparatus and the individual mounting of the capacitors in the rack is a lengthy operation. The defective capacitors are thereafter eliminated by sorting (stage 8).
In the process according to the invention, the capacitors after processing of the cathode (stage 4) are maintained in the frames and the latter are transferred to the ageing station (stage 10) where the anodes are immersed in a bed of semiconductor material and subjected to the ageing treatment as hereinafter explained in greater detail. Thereafter, the capacitors are sorted (stage 11) by simple visual inspection and released from the strips (stage 12). Only the sound capacitors are encapsulated (stage 12). A final sorting is effected, similar to stage 8 of the prior art. In the case of capacitors having plastic encapsulation, the latter is applied directly to the capacitors mounted on the frames.It will be seen from
Figure 1 that the ageing is an operation carried on on the individual capacitors in the case of the prior art, while it is an operation carried on on a batch in the case of the invention.
Figures 2 and 3 diagrammatically illustrate the ageing operation according to the invention. The capacitors, such as 21, are connected by their positive pole (tantalum wire 22) to a strip 23 of stainless steei or a bar supporting from 10 to 60 anodes depending upon their size (see Figure 3). These strips are combined in transfer racks 24 (see Figure 3) of 20, 40 or 80 strips, depending on the size of the anodes.
The rack is the production unit during all the subsequent manufacturing operations, as is explained in the foregoing.
In the course of stage 10, the strip is connected to the positive terminal of a stabilised voltage source 25 by way of a recording ammeter A. The second terminal of the source 25 is connected to a receptacle 26 containing a bed 27 of semiconductor material into which capacitors 21 are dipped. A voltmeter V displays the voltage across the terminals of 25. A ventilated oven, diagrammatically represented by the chain line 28, maintains the capacitors at the preset temperature. In a preferred variant, ageing is carried out by maintaining the voltage of the source 25 at between 1.2 and 1.8 times
the rated value and the temperature at between 250C and 1 800C, the treatment being continued for at
least two hours.The semiconductor bed 27 consists of manganese dioxide having a grain size of less than 350 ym, the anodes being immersed over two-thirds of their height. In order to obtain the effect of
individual limiting resistor for the anodes, the distance between the immersed end of the anode and the
receptacle 26 is to be about one centimetre. The pressure resulting from the weight of the rack is
sufficient to ensure electrical contact between the anodes and the bed. Current recording is continued throughout the ageing duration. At the end of the operation, the device is withdrawn from the oven and
the supply is switched off.A sorting may be carried out visually, whereby it is possible to eliminate the short-circtuited capacitors or capacitors having a strong leakage current, since they have changed in
appearance; these parts, which have been heated to a temperature above the melting temperature of the
tin or the stability temperature of the resin contained in the silvering coating, have often changed colour,
while in other cases grains of the semi-conductor bed have adhered to the anodes which have been
over-heated in the course of the ageing.
Figure 4 illustrates the distribution of the leakage currents (curve 41) before and (curve 42) after
ageing according to the prior art and (curve 43) after the ageing carried out in accordance with the
invention. The conditions of the ageing corresponding to the distribution 43 are the following: heating of the capacitors on a rack at 1 500C after immersion over tw,o-thirds of their height in a manganese dioxide bed, as explained in the foregoing, for two hours.Examination of the curves 41, 42,43 and more
particularly 42 and 43 shows that the accelerated ageing according to the present invention is
equivalent to that of the prior art in regard to the leakage current, because it will be seen that (curve 42) 64 capacitors have a leakage current of less than 0.05 yA during the ageing according to the prior art
and (curve 43) 62 capacitors have a leakage current below the same value, the two batches which have
served for comparison being taken from a common production. This number is 18 before ageing (curve
41).
Figure 5 and Table 1 show the influence of the parameters temperature and voltage on the ageing treatment, the duration having arbitrarily been maintained at the minimum value of two hours so as to
reduce the total manufacturing time. The histograms of Figure 5 correspond to batches of capacitors
taken from a common production of 22 F-40 V capacitors treated in the following manner:: batch No. 1 (curve 51) capacitors aged by the process according to the prior art batch No. 2 (curve 52) capacitors heated at 260C for two hours at 1.75 times the rated voltage
(70 V) batch No. 3 (curve 53) capacitors heated at 1 100C for two hours at 1.6 times the rated voltage
(65 V) batch No. 4 (curve 54) capacitors heated at 1 500C for two hours at 1.4 times the rated voltage
(56 V).
The distribution ranges over the leakage currents as in the preceding figure.
Comparison of the values of the parameters shows that the results are substantially constant. It
will be seen that an increase in the temperature substantially increases the number of capacitors having
a leakage current in the lowest range.
The table of Figure 6 shows the values of the parameters of typical capacitors of the four batches,
where
If is the leakage current
Fd is the dissipation factor and
AC is the variation of the capacitance between -550C and +850C and 250C respectively.
Figure 5 and Table 1 show that the number of capacitors with a leakage current lower than 0.5 A changes from 32 to 44 when the ageing temperature changes from 250C to 1 750C.
In the foregoing, a manganese dioxide bed has been used. Other semiconductors have also given good results, as shown by the following examples:
Example No. 1 - Check sample (ageing according to the prior art) Treatment at 85"C at the rated voltage for 15 hours 10 pF - 40 V capacitors
Before ageing After ageing
if Fd ACT If Fd ACT 0.2 2.1 5.5 0.45 2 5.3 0.7 1.5 5.3 0.2 1.5 5.3 0.1 1.4 5.2 0.04 1.4 5.2 0.1 1.5 5.7 0.05 1.5 5.1 0.9 1.9 5.9 0.25 1.5 5.5 Example No. 2 - Ageing in a ZnO bed at 150 C for 2 hours at 1.4 times the rated
voltage 10 1LF - 40 V capacitors
If Fd fez AC If Fd AC 0.5 2.1 5.8 0.45 2 5.9 0.2 1.7 5.9 0.18 1.7 6.1 0.1 1.4 5.6 0.09 1.4 5.5 0.09 1.8 5.8 0.07 1.7 5.5 0.05 1.7 5.5 0,04 1.8 5.3 1.5 1.9 5.3 1.2 1.8 5.1 Example No. 3 - Ageing in a graphite bed at 150"C for 2 hours at 1.4 times the
rated voltage 10 F - 40 V capacitors
If Fd AC If Fd AC 0.2 1.7 5.3 0.07 1.5 4.9 0.5 2 5.8 0.1 1.8 5.1 0.09 1.8 5.1 0.03 1.7 4.3 0.1 1.4 5.7 0.05 1.4 5.2 0.3 1.6 5.9 0.1 1.4 5.3 1 1.7 5.3 1.2 1.3 4.7 Example No. 4 - Ageing in the MnO bed at 150 C for 2 hours at 1.4 times the rated voltage 10 F-40.V F - 0, V capacitors.
Before ageing After ageing
If Fd ACT If Fd ACT 0.2 1.7 5.8 0.06 1.5 5 0.3 2 5.9 0.07 1.7 5.5 0.1 1.8 5.6 0.03 1.6 5.3 0.09 1.7 5.7 0.035 1.5 5.3 0.08 1.8 5.7 0.045 1.4 5.5 0.08 1.7 5.5 0.04 1.4 5.2 Example No. 5 Ageing in the MnO bed at 150"C for 2 hours at 1.4 times the
rated voltage 2.2 F - 40 V capacitors.
If Fd If Fd 0.03 2.2 0.016 1.8 0.74 2.1 0.012 1.4 0.036 1.7 0.015 1.3 1.70 1.5 0.22 1.2 80 1.9 0.52 1.4 0.5 2 0.03 1,5 It is of interest to note here that the curves recording the variation of the current in the course of the ageing show cases of self healing of capacitors.
For example, in Example No. 5, the capacitor corresponding to the penultimate line exhibits a leakage current of 80 4A before ageing; this current is reduced to 0.52 A after ageing.
TABLE 1
Measures before Measures after ageing ageing If C Fd If C Fd AC in % at (,uA) (off) (o/o) (MA) tyF) (%) -55" +85" 1.5 16.- 1.2 0.3 16.1 1.4 3.2 3.3 2.7 15.5 1.2 0.6 15.6 1.3 3.2 3.5 Conventional ageing 0.2 15.7 1.2 0.2 15.7 1.4 2.2 3.2 0.2 1655 1.3 0.1 16.5 1.3 3.6 3.2 0.9 14.9 1.2 0.4 14.9 1.4 3,3 3.7 0.6 15.5 1.1 0.1 15.7 1.2 2.6 3.6 0.7 15.5 1,1 0.3 15.7 1.2 2.7 4.2 at +25"C 0.8 16.5 1.2 0.3 16.4 1.2 2.5 3.4 70 V 0.7 15.7 1.1 0.2 15.8 1.2 2.3 3.2 2.1 15,9 1.1 0.1 15.9 1.2 2.7 3.6 1.1 15.7 1.1 0.7 15.8 1.2 2.4 4.2 1.1 15.7 1.1 0.7 15.8 1.2 2.4 4.2 0.5 15.9 1.1 0.4 15.7 1.1 2.8 3.7 at +1103C 0.5 16.- 1.1 0.5 16.- 1.1 2.9 4.2 65 V 0.3 15.8 1.1 0.3 15.7 1.2 2.4 3.4 0.5 15.7 1.2 0.5 15.6 1.2 2.3 4.1 0.1 16.3 1,1 0.3 16.3 1.8 5.- 5.5 0,4 16.2 1.1 0.1 16.2 1.8 4.5 5.2 at +150 C 0.8 15.7 1.3 0.2 15.9 1.7 3.5 4.2 56 V 2.6 16.- 1.2 0.6 16.1 1.9 5.1 5. 0.9 16.2 1.2 0.3 16.3 1.7 4.3 5.6
Claims (4)
1. A process for accelerated ageing of tantalum solid-electrolyte capacitors, characterised in that the capacitors mounted on a strip production unit are immersed into a bed of pulverous semiconducting material contained in a conductive receptacle connected to the negative terminal of a stabilised-voltage source, of which the positive terminal is directly connected to the strip to which the anodes of the capacitors are fixed, the voltage of the said source being between 1.2 and 1.8 times the rated voltage of the capacitors, and the said mounting being maintained between 250C and 1 800C for a minimum period of two hours.
2. A process for accelerated ageing tantalum solid-electrolyte capacitors according to Claim 1, wherein the said bed consists of a semiconducting oxide.
3. A process for ageing tantalum solid-electrolyte capacitors according to Claim 2, wherein the said bed consists of manganese dioxide.
4. A process for ageing tantalum solid-electrolyte capacitors according to Claim 3, wherein the temperature is 15O0C and the applied voltage is 1.4 times the rated voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7921295A GB2026773B (en) | 1979-06-19 | 1979-06-19 | Process for the manufacture of tantalum solid electrolyte capacitors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7921295A GB2026773B (en) | 1979-06-19 | 1979-06-19 | Process for the manufacture of tantalum solid electrolyte capacitors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2026773A true GB2026773A (en) | 1980-02-06 |
| GB2026773B GB2026773B (en) | 1982-09-02 |
Family
ID=10505943
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7921295A Expired GB2026773B (en) | 1979-06-19 | 1979-06-19 | Process for the manufacture of tantalum solid electrolyte capacitors |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2026773B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2121604A (en) * | 1982-05-18 | 1983-12-21 | Standard Telephones Cables Ltd | Method of making a solid electrolytic capacitor |
| US4929316A (en) * | 1988-09-02 | 1990-05-29 | Niksuko Corporation | Method of manufacturing organic semi-conductor solid electrolytic capacitor |
| US4934033A (en) * | 1987-01-23 | 1990-06-19 | Nitsuko Corporation | Method of manufacturing a solid electrolytic capacitor |
| EP1644947A2 (en) * | 2003-07-10 | 2006-04-12 | Showa Denko K.K. | Jig for producing capacitor, production method for capacitor and capacitor |
-
1979
- 1979-06-19 GB GB7921295A patent/GB2026773B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2121604A (en) * | 1982-05-18 | 1983-12-21 | Standard Telephones Cables Ltd | Method of making a solid electrolytic capacitor |
| US4934033A (en) * | 1987-01-23 | 1990-06-19 | Nitsuko Corporation | Method of manufacturing a solid electrolytic capacitor |
| US4929316A (en) * | 1988-09-02 | 1990-05-29 | Niksuko Corporation | Method of manufacturing organic semi-conductor solid electrolytic capacitor |
| EP1644947A2 (en) * | 2003-07-10 | 2006-04-12 | Showa Denko K.K. | Jig for producing capacitor, production method for capacitor and capacitor |
| EP1644947A4 (en) * | 2003-07-10 | 2007-08-22 | Showa Denko Kk | Jig for producing capacitor, production method for capacitor and capacitor |
| US7819928B2 (en) | 2003-07-10 | 2010-10-26 | Showa Denko K.K. | Jig for producing capacitor, production method for capacitor and capacitor |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2026773B (en) | 1982-09-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |