US2035022A - Electrolytic device - Google Patents
Electrolytic device Download PDFInfo
- Publication number
- US2035022A US2035022A US1432A US143235A US2035022A US 2035022 A US2035022 A US 2035022A US 1432 A US1432 A US 1432A US 143235 A US143235 A US 143235A US 2035022 A US2035022 A US 2035022A
- Authority
- US
- United States
- Prior art keywords
- electrode
- aluminum
- film
- electrodes
- formation
- 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
- 238000000034 method Methods 0.000 description 25
- 229910052782 aluminium Inorganic materials 0.000 description 23
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 23
- 230000015572 biosynthetic process Effects 0.000 description 20
- 239000003792 electrolyte Substances 0.000 description 17
- 230000002378 acidificating effect Effects 0.000 description 11
- 238000004140 cleaning Methods 0.000 description 11
- 239000012670 alkaline solution Substances 0.000 description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 229910021538 borax Inorganic materials 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000004328 sodium tetraborate Substances 0.000 description 5
- 235000010339 sodium tetraborate Nutrition 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 239000003518 caustics Substances 0.000 description 4
- -1 filings Substances 0.000 description 4
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 3
- 239000004327 boric acid Substances 0.000 description 3
- 230000002401 inhibitory effect Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000002939 deleterious effect Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- 235000011121 sodium hydroxide Nutrition 0.000 description 2
- 239000001488 sodium phosphate Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 159000000011 group IA salts Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- QHGVXILFMXYDRS-UHFFFAOYSA-N pyraclofos Chemical compound C1=C(OP(=O)(OCC)SCCC)C=NN1C1=CC=C(Cl)C=C1 QHGVXILFMXYDRS-UHFFFAOYSA-N 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 235000019795 sodium metasilicate Nutrition 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 235000011008 sodium phosphates Nutrition 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 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
- H01G9/0032—Processes of manufacture formation of the dielectric layer
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S205/00—Electrolysis: processes, compositions used therein, and methods of preparing the compositions
- Y10S205/917—Treatment of workpiece between coating steps
Definitions
- Such films consist of partially hydrated aluminum oxide and have a uni-directional character.
- alkaline cleansers for such purpose, have been unsuccessful so far, because an excessive amount of alkaline material was required to properly clean the electrode.
- the alkaline material attacked and pitted the aluminum to such an extent, particularly around metal impurities in the surface, that it was unfeasible to form a good quality film on the electrodes so cleaned, particularly in the neighborhood of the exposed impurities.
- a strongly alkaline solvent can be overcome, respectively changed in character, by adding to such solventwhich for instance may be caustic sodaa suitablev inhibiting agent, such as sodium phophate, sodium meta-silicate, sodium fluoride, etc.
- caustic sodaa suitablev inhibiting agent such as sodium phophate, sodium meta-silicate, sodium fluoride, etc.
- the strong local action of the alkali is thereby transformed into an evenly distributed moderate action and the aluminum, instead of being pitted and damaged in spots, is evenly etched over its whole surface.
- caustic reagent is required.
- the electrodes are preferably subjected to rinsing.
- the cleaned electrode when left exposed to air, oxidizes on its surface and this oxide layer is just as objectionable as the oxide film'formed in an acidic cleaner.
- the electrodes instead of being subjected to a preliminary chemical cleaning, undergo a preliminary forming process, which consists of placing the electrodes in a slightly acidic electrolyte, for instance, borax and boric acid in which the electrodes are subjected to a short formation.
- a preliminary forming process which consists of placing the electrodes in a slightly acidic electrolyte, for instance, borax and boric acid in which the electrodes are subjected to a short formation.
- a thin oxide film covers the electrode, which film also includes the surface contaminations of the aluminum.
- the electrodes are submerged in an alkaline solution, for instance, borax, sodium phosphate, etc., which attacks and removes the preliminary film without oxidizing or attacking the aluminum. Thereafter; the electrodes are subjected to the regular forming process, preferably in a slightly acidic electrolyte.
- an alkaline solution for instance, borax, sodium phosphate, etc.
- a third method of obtaining the same or siml lar results is the following:
- an alkaline electrolyte for instance, borax.
- Current is now applied, whereby a film is formed on the electrode but partly attacked by the borax,
- the electrolyte is made slightly acidic by addition of boric acid and the electrode subjected to the regular formation process.
- a fourth method is similar to the third and consists in placing the electrode without preliminary cleaning in the forming tank, which again comprises an alkaline solution as caustic soda, but instead of applying a forming current, the caustic soda is left chemically to clean the aluminum-preferablyin the presence of inhibitive agents-as described in connection with the first method.
- the electrolyte is made acidic, for instance, by addition of boric acid and the forming process undertaken in the regular way.
- grade A aluminum having 99.6% to 99.7% aluminum is subjected to corrosion in air
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
Patented Mar. 24, 1936 ELECTROLYTIC DEVICE Preston Robinson, Williamstown, and Joseph L. Collins, North Adams, Mass., assignors to Snr zue Specialties Company, North Adams, Mass., a corporation of Massachusetts No Drawing. Original application Mam." 28,
1931, Serial No. 526,118. Divided and this application January 11, 1935, Serial No. 1,432. In Canada August 4, 1932 6 Claims. (01. 1'75-315) Our invention relates to electrolytic devices, acidic bath and subsequently rinsing them in densers-otherwise such as electrolytic condensers, rectifiers, or the like, comprising film-forming electrodes, this application being a division of our copending application Ser. No. 526,118, filed March 28, 1931.
In such devices use is made of the film-forming effect exhibited by certain metals, for instance aluminum which, when placed in suitable electrolytes, upon application of the proper volt age are covered with a film. Such films consist of partially hydrated aluminum oxide and have a uni-directional character.
We shall describe our invention in its application to electrolytic condensers, using aluminum electrodes, although it should be well understood that our invention is not limited to such devices or electrode material.
We .have found that the oxide layer which forms on aluminum, when exposed to the action of acids or to air, while chemically similar to the substance of the film built up in the electrolytic forming process, substantially diifers therefrom in its insulating and dielectric properties. We have also found that if an aluminum electrode, before it is subjected to electrolytic formation, is covered by such an oxide layer, such layer disadvantageously influences film formation, respectively, the properties of the films obtained. More specifically we have found that condensers having electrodes, which were thus oxidized prior to their formation have higher power factor and smaller effective capacity than conidentical-in which trodes are used on which oxidization before film formation has been prevented.
It is, therefore, one object of our invention to provide films of 'improved qualities by preventing oxidization of the electrode surface prior to the formation of the film.
Other objects of our invention will appear as the specification progresses.
As in the manufacture and handling of the electrodes impurities such as filings, grease, etc., are deposited on and adhere to the electrode surface, the deleterious influence of which is well recognized, it is practice to clean the electrodes before subjecting them to the film-forming process.
In the-past, such cleaning was effected by subjecting the aluminum electrodes to an aqueous water. However, the acid while removing the impurities from the surface of the aluminum, also dissolves the outer layer of aluminum, and-. due to the water present-forms an oxide layer 5 on the electrode. This oxide layer is not removed through rinsing and its presence, as stated above, deleteriously aflects the quality of the dielectric film.
We have found that by immersing the aluminum in a properly prepared alkaline solution, we can remove the impurities just as effectively as with an acidic cleanser without forming an oxide layer on the aluminum.
Attempts to use alkaline cleansers for such purpose, have been unsuccessful so far, because an excessive amount of alkaline material was required to properly clean the electrode. In addition, the alkaline material attacked and pitted the aluminum to such an extent, particularly around metal impurities in the surface, that it was unfeasible to form a good quality film on the electrodes so cleaned, particularly in the neighborhood of the exposed impurities.
To prevent pitting of the aluminum, it has been suggested to treat the anodes in a weakly alkaline solution such as borax or trisodium phosphate which will attack aluminum oxide or hydroxide, but which will not strongly attack aluminum. However, in order to obtain complete cleaning with such reagents, it would be necessary to operate at very high temperatures and for long continued times, which is objectionable and uneconomical.
We have found that the pitting action of a strongly alkaline solvent can be overcome, respectively changed in character, by adding to such solventwhich for instance may be caustic sodaa suitablev inhibiting agent, such as sodium phophate, sodium meta-silicate, sodium fluoride, etc. The strong local action of the alkali is thereby transformed into an evenly distributed moderate action and the aluminum, instead of being pitted and damaged in spots, is evenly etched over its whole surface. At the same time, only a small amount of caustic reagent is required.
Thus by using a caustic cleanser in the presence of proper inhibiting agents, objectionable 'cxidization of the electrode is prevented, and at the same time through evenly distributed etching of the aluminum surface, the effective area of the electrode is considerably increased.
After their cleaning in a caustic solvent, the electrodes are preferably subjected to rinsing.
However, we have found that objectionable Oxidization of the electrode before it is formed is not fully prevented even by alkaline cleaning.
because, as above stated, the cleaned electrode when left exposed to air, oxidizes on its surface and this oxide layer is just as objectionable as the oxide film'formed in an acidic cleaner.
Even relatively short exposures to air of the cleaned electrodes cause a marked increase in power factorand decrease in capacity, and such deleterious effects increase ,with the duration of such exposure; and we found that the lowest power factors and maximum capacities are obtained when the electrodes, after their cleansing and rinsing are immediately submerged in the forming electrolyte and subjected to formation therein. 1
For instance, taking two electrodes of identical construction and cleaned by the same process and leaving one before its formation for half an hour exposed to air, while subjecting the other to the forming process immediately after its cleaning,
we have found the following: The capacity of the condenser using the first electrode was 6.2 mfd. and its power factor 24%,
while the condenser using the second electrode the capacity was 7.1 mfd. and the power factor 15%.
In practice, therefore, after we have cleaned the electrodes in a proper alkaline solution and subsequently rinsed them preferably in a very weak alkaline solution-as a diluted solution of borax-we transfer the electrodes from the cleaning bath immediately into the forming tank and subject them therein immediately to formation, whereby the electrolyte used inthe formation process is preferably slightly acidic.
Instead of using the above described method, we have found that undesirable oxidization of the electrode can be prevented by a second method as follows:
The electrodes, instead of being subjected to a preliminary chemical cleaning, undergo a preliminary forming process, which consists of placing the electrodes in a slightly acidic electrolyte, for instance, borax and boric acid in which the electrodes are subjected to a short formation. As a result of this formation, a thin oxide film covers the electrode, which film also includes the surface contaminations of the aluminum.
After such preliminary formation, the electrodes are submerged in an alkaline solution, for instance, borax, sodium phosphate, etc., which attacks and removes the preliminary film without oxidizing or attacking the aluminum. Thereafter; the electrodes are subjected to the regular forming process, preferably in a slightly acidic electrolyte.
In using this method, it is sometimes found advisable to have the alkaline solution only dissolve such outer portion of the preliminary film which actually contains the impurities, and to leave the inner portion of the film adhering to the electrode.
A third method of obtaining the same or siml lar results is the following:
The electrode, without preliminary cleaning,
is placed in the forming tank which contains an alkaline electrolyte, for instance, borax. Current is now applied, whereby a film is formed on the electrode but partly attacked by the borax, Hereafter the electrolyte is made slightly acidic by addition of boric acid and the electrode subjected to the regular formation process.
A fourth method is similar to the third and consists in placing the electrode without preliminary cleaning in the forming tank, which again comprises an alkaline solution as caustic soda, but instead of applying a forming current, the caustic soda is left chemically to clean the aluminum-preferablyin the presence of inhibitive agents-as described in connection with the first method. After a short. period of alkaline cleaning of the electrode, the electrolyte is made acidic, for instance, by addition of boric acid and the forming process undertaken in the regular way.
We have also found that while the highest quality commercially available aluminum, the so-called grade A" aluminum, having 99.6% to 99.7% aluminum is subjected to corrosion in air,
an aluminum of 99.9% or higher purity, does not special precaution is required to prevent the elec-- trode from corroding in air before it is subjected to formation.
In the foregoing we have described various methods to prevent objectionable oxidation of aluminum electrodes during or subsequent to their cleaning and to obtain higher quality oxide films. While we have illustrated our invention in connection with electrolytic condensers, using aluminum electrodes and described specific methods, we do not wish to be limited to such devices, material or methods, but desire the appended claims to be construed as broadly as permissible in view of the prior art.
What we, therefore, claim and desire to secure by Letters Patent is:
1. In the manufacture of film-forming electrodes for. electrolytic condensers, the process which comprises subjecting the electrode to a preliminary forming process in a slightly acidic electrolyte, dissolving the film so formed in an alkaline solution and subjecting thereafter the electrode to a' final film formation.
2. In the manufacture of film-forming elec trodes for electrolytic devices, the process which comprises subjecting the electrode to a preliminary fllm formation in an electrolyte, dissolving the outer portion of the film by immersing the electrode in an alkaline solution and subjecting the electrode thereafter to a final forming process.
3. In the manufacture of an aluminum-electrode, the process which comprises subjecting the electrode to film formation in an electrolyte comprising an alkaline salt of a weak acid and subsequently adding an excess of a weak acid to the electrolyte and completing film formation in the acidic electrolyte.
' 4. In the manufacture of aluminum electrodes nary film-formation in an electrolyte, dissolving the outer portion of the film and subjecting the electrode thereafter to a final forming process.
6. In the manufacture. of film forming electrodes for electrolytic devices the process which comprises, subjecting the electrode to a preliminary film formation in an acidic electrolyte, Greating the electrode in an electrolyte having a pH higher than 7 and subsequently placing the electrode in an electrolyte having a pH lower than 7 while applying to the electrode a voltage-effecting film formation.
PRESTON ROBINSON. JOSEPH L. COLLINS.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US1432A US2035022A (en) | 1931-03-28 | 1935-01-11 | Electrolytic device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US526118A US2067703A (en) | 1931-03-28 | 1931-03-28 | Electrolytic device |
US1432A US2035022A (en) | 1931-03-28 | 1935-01-11 | Electrolytic device |
Publications (1)
Publication Number | Publication Date |
---|---|
US2035022A true US2035022A (en) | 1936-03-24 |
Family
ID=26669022
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US1432A Expired - Lifetime US2035022A (en) | 1931-03-28 | 1935-01-11 | Electrolytic device |
Country Status (1)
Country | Link |
---|---|
US (1) | US2035022A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE922896C (en) * | 1938-08-16 | 1955-01-27 | Siemens Ag | Method of manufacturing a selenium rectifier |
DE925330C (en) * | 1950-08-29 | 1955-03-17 | Gen Electric | Process for the electrolytic etching of tantalum |
US3079536A (en) * | 1959-09-21 | 1963-02-26 | Bell Telephone Labor Inc | Film-forming metal capacitors |
US3156633A (en) * | 1962-02-21 | 1964-11-10 | Bell Telephone Labor Inc | Film-forming metal capacitors |
DE1212214B (en) * | 1956-04-06 | 1966-03-10 | Siemens Ag | Operating electrolyte for tantalum electrolytic capacitors |
-
1935
- 1935-01-11 US US1432A patent/US2035022A/en not_active Expired - Lifetime
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE922896C (en) * | 1938-08-16 | 1955-01-27 | Siemens Ag | Method of manufacturing a selenium rectifier |
DE925330C (en) * | 1950-08-29 | 1955-03-17 | Gen Electric | Process for the electrolytic etching of tantalum |
DE1212214B (en) * | 1956-04-06 | 1966-03-10 | Siemens Ag | Operating electrolyte for tantalum electrolytic capacitors |
US3079536A (en) * | 1959-09-21 | 1963-02-26 | Bell Telephone Labor Inc | Film-forming metal capacitors |
US3156633A (en) * | 1962-02-21 | 1964-11-10 | Bell Telephone Labor Inc | Film-forming metal capacitors |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3111979B2 (en) | Wafer cleaning method | |
JP2010109384A (en) | Method of removing metal in scrubber | |
KR102317276B1 (en) | Method for manufacturing electrode foil for surface mount aluminum electrolytic capacitors | |
US2079516A (en) | Aluminum electrode and method of preparing | |
US2035022A (en) | Electrolytic device | |
US3625908A (en) | Composition for cleaning photographic equipment | |
CN103774193A (en) | Method for electrolytic-depositing dispersed zinc crystal nucleuses on surface of medium-high voltage electronic aluminum foil | |
US6524965B2 (en) | Cleaning method for semiconductor manufacturing process to prevent metal corrosion | |
US2067703A (en) | Electrolytic device | |
US1935395A (en) | Film formation on valve metals | |
JPS5825218A (en) | Method of producing low voltage electrolytic condenser electrode foil | |
US2193711A (en) | Electrolytic device | |
US2206050A (en) | Electrolytic device | |
US1705944A (en) | Electrolytic device | |
US3378668A (en) | Method of making non-porous weld beads | |
US2197632A (en) | Electrical rectifier | |
US2086993A (en) | Condenser and method of producing same | |
US2361680A (en) | Method of reducing edge leakage in metal oxide-metal rectifiers | |
JPH1197298A (en) | Method of manufacturing electrode foil for aluminum electrolytic capacitor | |
US2830942A (en) | Electrocleaner for brass | |
US2062464A (en) | Anodes, method of forming the same, and formation electrolyte therefor | |
JP2009105242A (en) | Method of manufacturing electrode foil for electrolytic capacitor | |
US1773160A (en) | Process for cupric-oxide removal | |
US2154026A (en) | Cathode for electrolytic devices | |
US1451758A (en) | Manufacture of dry-battery cans |