US3617456A - Bath for the electrolytic stripping of galvanic coatings made of nickel, chromium or gold from base bodies made of copper, copper alloys, silver, zinc or titanium - Google Patents
Bath for the electrolytic stripping of galvanic coatings made of nickel, chromium or gold from base bodies made of copper, copper alloys, silver, zinc or titanium Download PDFInfo
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- US3617456A US3617456A US771349A US3617456DA US3617456A US 3617456 A US3617456 A US 3617456A US 771349 A US771349 A US 771349A US 3617456D A US3617456D A US 3617456DA US 3617456 A US3617456 A US 3617456A
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- Prior art keywords
- phenol
- bath
- stripping
- copper
- silver
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 238000000576 coating method Methods 0.000 title claims abstract description 19
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 15
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 14
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 14
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 14
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 14
- 239000010949 copper Substances 0.000 title claims abstract description 14
- 229910052709 silver Inorganic materials 0.000 title claims abstract description 14
- 239000004332 silver Substances 0.000 title claims abstract description 14
- 239000010936 titanium Substances 0.000 title claims abstract description 14
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 14
- 229910052725 zinc Inorganic materials 0.000 title claims abstract description 14
- 239000011701 zinc Substances 0.000 title claims abstract description 14
- 229910000881 Cu alloy Inorganic materials 0.000 title claims abstract description 12
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 11
- 229910052804 chromium Inorganic materials 0.000 title claims abstract description 11
- 239000011651 chromium Substances 0.000 title claims abstract description 11
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 10
- 229910052737 gold Inorganic materials 0.000 title claims abstract description 10
- 239000010931 gold Substances 0.000 title claims abstract description 10
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 38
- SOIFLUNRINLCBN-UHFFFAOYSA-N ammonium thiocyanate Chemical compound [NH4+].[S-]C#N SOIFLUNRINLCBN-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000010953 base metal Substances 0.000 claims abstract description 6
- 238000005260 corrosion Methods 0.000 claims abstract description 6
- 230000007797 corrosion Effects 0.000 claims abstract description 6
- MGSRCZKZVOBKFT-UHFFFAOYSA-N thymol Chemical compound CC(C)C1=CC=C(C)C=C1O MGSRCZKZVOBKFT-UHFFFAOYSA-N 0.000 claims description 12
- WQGWDDDVZFFDIG-UHFFFAOYSA-N pyrogallol Chemical compound OC1=CC=CC(O)=C1O WQGWDDDVZFFDIG-UHFFFAOYSA-N 0.000 claims description 10
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 claims description 9
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 claims description 8
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 claims description 6
- IQUPABOKLQSFBK-UHFFFAOYSA-N 2-nitrophenol Chemical compound OC1=CC=CC=C1[N+]([O-])=O IQUPABOKLQSFBK-UHFFFAOYSA-N 0.000 claims description 6
- 239000005844 Thymol Substances 0.000 claims description 6
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 claims description 6
- 229930003836 cresol Natural products 0.000 claims description 6
- 229960000790 thymol Drugs 0.000 claims description 6
- JINHZAXMOALKLT-UHFFFAOYSA-N 1,6-dimethyl-5-nitrocyclohexa-2,4-dien-1-ol Chemical compound [N+](=O)([O-])C=1C(C(C=CC1)(C)O)C JINHZAXMOALKLT-UHFFFAOYSA-N 0.000 claims description 5
- GAKLFAZBKQGUBO-UHFFFAOYSA-N 2-methyl-3-nitrophenol Chemical compound CC1=C(O)C=CC=C1[N+]([O-])=O GAKLFAZBKQGUBO-UHFFFAOYSA-N 0.000 claims description 5
- CYUYOFIGNXMLPJ-UHFFFAOYSA-N 3-methyl-2-nitro-6-propan-2-ylphenol Chemical compound CC(C)C1=CC=C(C)C([N+]([O-])=O)=C1O CYUYOFIGNXMLPJ-UHFFFAOYSA-N 0.000 claims description 5
- UFBJCMHMOXMLKC-UHFFFAOYSA-N 2,4-dinitrophenol Chemical compound OC1=CC=C([N+]([O-])=O)C=C1[N+]([O-])=O UFBJCMHMOXMLKC-UHFFFAOYSA-N 0.000 claims description 4
- YHKWFDPEASWKFQ-UHFFFAOYSA-N 3-nitrobenzene-1,2-diol Chemical compound OC1=CC=CC([N+]([O-])=O)=C1O YHKWFDPEASWKFQ-UHFFFAOYSA-N 0.000 claims description 4
- JPYHHZQJCSQRJY-UHFFFAOYSA-N Phloroglucinol Natural products CCC=CCC=CCC=CCC=CCCCCC(=O)C1=C(O)C=C(O)C=C1O JPYHHZQJCSQRJY-UHFFFAOYSA-N 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 4
- QCDYQQDYXPDABM-UHFFFAOYSA-N phloroglucinol Chemical compound OC1=CC(O)=CC(O)=C1 QCDYQQDYXPDABM-UHFFFAOYSA-N 0.000 claims description 4
- 229960001553 phloroglucinol Drugs 0.000 claims description 4
- 229940079877 pyrogallol Drugs 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 3
- GGNQRNBDZQJCCN-UHFFFAOYSA-N benzene-1,2,4-triol Chemical compound OC1=CC=C(O)C(O)=C1 GGNQRNBDZQJCCN-UHFFFAOYSA-N 0.000 claims description 3
- 229960004337 hydroquinone Drugs 0.000 claims description 3
- 229960001755 resorcinol Drugs 0.000 claims description 3
- 125000002256 xylenyl group Chemical class C1(C(C=CC=C1)C)(C)* 0.000 claims 2
- 229910052751 metal Inorganic materials 0.000 abstract description 6
- 239000002184 metal Substances 0.000 abstract description 6
- 230000002950 deficient Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 150000003739 xylenols Chemical class 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- -1 for example Chemical compound 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 150000002989 phenols Chemical class 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- ZMZDMBWJUHKJPS-UHFFFAOYSA-N thiocyanic acid Chemical compound SC#N ZMZDMBWJUHKJPS-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 150000002828 nitro derivatives Chemical class 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 150000003567 thiocyanates Chemical class 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZMZDMBWJUHKJPS-UHFFFAOYSA-M Thiocyanate anion Chemical compound [S-]C#N ZMZDMBWJUHKJPS-UHFFFAOYSA-M 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- RBXVOQPAMPBADW-UHFFFAOYSA-N nitrous acid;phenol Chemical class ON=O.OC1=CC=CC=C1 RBXVOQPAMPBADW-UHFFFAOYSA-N 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F5/00—Electrolytic stripping of metallic layers or coatings
Definitions
- the present invention relates to a novel electrolyticstripping bath for the detachment of galvanic deposits of chromium, nickel or gold from base metal bodies made of copper and copper alloys, silver, zinc, or titanium, the main stripping component of the bath consisting of an aqueous solution of a water-soluble salt of thiocyanic acid,-preferably a solution of ammonium thiocyanate, in the presence of a watersoluble phenol.
- the water -soluble phenol is selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, oxyhydroquinone, nitrophenol, dinitrophenol, nitropyrocatechol, cresol, nitrocresol, thymol, nitrothymol, xylenol and nitroxylenol.
- the amount of phenol which is employed is lessthan the amount of ammonium thiocyanate. Without the phenol, the electrolytic stripping is inefficient because the base metal is pitted and corroded by the electrolytic-stripping solution.
- lt is known to strip copper, silver, zinc or titanium objects of their defective coatings of the above-mentioned types by dipping them into a suitable chemical bath, e.g., a strong 1 mineral acid.
- a suitable chemical bath e.g., a strong 1 mineral acid.
- such chemical baths require long coatings electrolytically in strong sulfuric acid but, in this case, the base material is substantially attacked and the stripping time is much too long.
- the defective coatings of the above-mentioned types can be detached more effectively and more rapidly by the electrolytic method, whereby the object that is to be treated is dipped into a galvanic bath as the anode and the bath is adjusted with a pitting preventative agent consisting of a water-soluble phenol which is present in anamount less than the dry weight of the thiocyanate salt.
- the present invention thus provides a galvanic bath for the electrolytic detachment of galvanic coatings of chromium, nickel, or gold from base bodies of copper, copper alloys, silver, zinc or titanium which overcomes the disadvantages of the known thiocyanate salt baths.
- the present invention also provides the advantage that a waterrepellent layer permeable to the stripping current is formed on the base material consisting of copper, copper alloys, silver, zinc or titanium during the detaching process and this layer prevents corrosion of the base body.
- the protective layer can be removed later on by dipping the base body into a diluted caustic soda solution.
- phenol C H OH and/or nitrophenol C I-LNOOH are preferred to use since these phenols have good solubility and are of relatively low cost.
- dihydroxybenzene Panechol, resorcinol, hydroquinone
- trihydroxybenzene pyrogallol, phloroglucinol, oxyhydroxyquinone
- their nitro compounds especially nitropyrocatechol C,l-l,N0,(0H dinitrophenol C H,(NO ),Ol-I, as additive to the bath.
- the homologues of the phenol for example, cresol, thymol or xylenol, and their nitro compounds are also suitable as additives to the bath.
- All of the foregoing phenols of the invention are seen to be water-soluble aromatic hydroxyl compounds with at least one unsubstituted hydroxyl in the benzene ring.
- those baths have proven to be particularly suitable which contain 50 to 300 grams of ammonium thiocyanate and 5 to grams of a phenol, such as C l-LOH, per liter of liquid bath. 7
- the base body made of copper, copper alloys, silver, zinc or titanium, which is to be freed of its metallic coating, dull-finish nickel for an example, is immersed in the bath and connected as an anode.
- a stainless steel metal sheet can be used as cathode.
- 8 ampere/dm. is provided.
- the pH value of the bath lies 6 to 6.5 and does not need to be regulated by the addition of any buffers or other acidity regulating chemicals.
- EXAMPLE A solution consisting of 75 g. of ammonium thiocyanate and 50 g. of phenol per one liter of water was produced.
- the base body was connected as the anode and a metal plate made of stainless steel was used as cathode.
- An aqueous electrolytic stripping bath to remove nickel, chromium, or gold coatings from copper, copper alloys, silver, zinc or titanium metal articles comprising water-soluble thiocyanate as the stripping component in an amount of 50-300 grams per liter and a phenol which is a water-soluble aromatic hydroxyl compound with at least one unsubstituted hydroxyl in the benzene ring to accelerate the stripping and reduce corrosion of the base metal in an amount of 5-80 grams per liter.
- phenol is selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, oxyhydroquinone, nitrophenol, dinitrophenol,
- a stripping bath as claimed in claim 1 phenol is xylenol.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Prevention Of Electric Corrosion (AREA)
Abstract
An aqueous electrolytic-stripping bath to remove nickel, chromium, or gold coatings from copper, copper alloy, silver, zinc, or titanium metal articles comprising ammonium thiocyanate as the stripping component and a phenol to accelerate the stripping and to reduce corrosion of the base metal.
Description
United States Patent Inventor Appl. No. Filed Patented Horst Dillenberg Koniggratzer Strasse 25, Haan, Germany 771,349
Oct. 28, 1968 Nov. 2, 1971 BATH FOR THE ELECTROLYTIC STRIPPING OF GALVANIC COATINGS MADE OF NICKEL, CHROMIUM OR GOLD FROM BASE BODIES MADE OF COPPER, COPPER ALLOYS, SILVER,
ZINC OR TITANIUM 10 Claims, No Drawings US. Cl 204/146 Int. Cl 8011- 1/00, B0 1 r 3/00 Field of Search 204/ 146 Primary Examiner-John H. Mack Assistant Examiner-R. J. Fay Attorney-Abraham A. Saffitz ABSTRACT: An aqueous electrolytic-stripping bath to remove nickel, chromium, or gold coatings from copper, copper alloy, silver, zinc, or titanium metal articles comprising ammonium thiocyanate as the stripping component and a phenol to accelerate the stripping and to reduce corrosion of the base metal.
BATH FOR THE ELECTROLYTIC STRIPPING OF GALVANIC COATINGS MADE OF NICKEL, CHROMIUM OR GOLD FROM BASE BODIES MADE OF COPPER, COPPER ALLOYS, SILVER, ZINC OR TITANIUM The present invention relates to a novel electrolyticstripping bath for the detachment of galvanic deposits of chromium, nickel or gold from base metal bodies made of copper and copper alloys, silver, zinc, or titanium, the main stripping component of the bath consisting of an aqueous solution of a water-soluble salt of thiocyanic acid,-preferably a solution of ammonium thiocyanate, in the presence of a watersoluble phenol. Preferably, the water -soluble phenol is selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, oxyhydroquinone, nitrophenol, dinitrophenol, nitropyrocatechol, cresol, nitrocresol, thymol, nitrothymol, xylenol and nitroxylenol.
The amount of phenol which is employed is lessthan the amount of ammonium thiocyanate. Without the phenol, the electrolytic stripping is inefficient because the base metal is pitted and corroded by the electrolytic-stripping solution.
During thegalvanic coatings of metal objects made from copper, silver, zinc or titanium, such as the hoods of headlights, armatures, etc., the defective coatings which are ascertained by inspection must be removed and it is necessary to strip these defective coatings before the objects can again be coated galvanically. The mechanical removal of defective coatings by brushing or abrading requires a substantial work expenditure, skilled workmen and high costs; and, in the case of objects which have a complicated structure, the mechanical removal cannot be carried out at all.
lt is known to strip copper, silver, zinc or titanium objects of their defective coatings of the above-mentioned types by dipping them into a suitable chemical bath, e.g., a strong 1 mineral acid. However, such chemical baths require long coatings electrolytically in strong sulfuric acid but, in this case, the base material is substantially attacked and the stripping time is much too long.
ln accordance with the present invention, the defective coatings of the above-mentioned types can be detached more effectively and more rapidly by the electrolytic method, whereby the object that is to be treated is dipped into a galvanic bath as the anode and the bath is adjusted with a pitting preventative agent consisting of a water-soluble phenol which is present in anamount less than the dry weight of the thiocyanate salt.
When working with such a galvanic bath consisting of an aqueous solution of ammonium thiocyanate without a phenol, various weaknesses of the stripping operation will appear; namely, (1) the protective layer which is formed is not uniform and homogeneous on the base material so that pitting occurs and (2) semiglossy and dull-finish nickel layers are stripped very slowly.
The present invention thus provides a galvanic bath for the electrolytic detachment of galvanic coatings of chromium, nickel, or gold from base bodies of copper, copper alloys, silver, zinc or titanium which overcomes the disadvantages of the known thiocyanate salt baths.
A large number of practical tests which have been carried out by the inventor have shown that the addition of a watersoluble phenol or a homologue of the phenol increases the speed of stripping or removal of electrolytically applied coatings of nickel, chromium and gold and especially reduce the stripping time of dull-finish or semiglossy nickel. The present invention also provides the advantage that a waterrepellent layer permeable to the stripping current is formed on the base material consisting of copper, copper alloys, silver, zinc or titanium during the detaching process and this layer prevents corrosion of the base body. The protective layer can be removed later on by dipping the base body into a diluted caustic soda solution.
It is preferred to use phenol C H OH and/or nitrophenol C I-LNOOH as the additive to the bath since these phenols have good solubility and are of relatively low cost. For this purpose of the invention, one can also use multivalent phenols and/or multivalent nitrophenols as an additive to the bath. For example, one can use dihydroxybenzene (Pywcatechol, resorcinol, hydroquinone), trihydroxybenzene (pyrogallol, phloroglucinol, oxyhydroxyquinone) or their nitro compounds, especially nitropyrocatechol C,l-l,N0,(0H dinitrophenol C H,(NO ),Ol-I, as additive to the bath. Likewise, the homologues of the phenol, for example, cresol, thymol or xylenol, and their nitro compounds are also suitable as additives to the bath. All of the foregoing phenols of the invention are seen to be water-soluble aromatic hydroxyl compounds with at least one unsubstituted hydroxyl in the benzene ring.
In practice, those baths have proven to be particularly suitable which contain 50 to 300 grams of ammonium thiocyanate and 5 to grams of a phenol, such as C l-LOH, per liter of liquid bath. 7
According to the present invention, one operates with the bath as follows:
The base body made of copper, copper alloys, silver, zinc or titanium, which is to be freed of its metallic coating, dull-finish nickel for an example, is immersed in the bath and connected as an anode. A stainless steel metal sheet can be used as cathode. As a minimum amperage, 8 ampere/dm. is provided. One operates in a temperature range of 20 C. to 60 C. The pH value of the bath lies 6 to 6.5 and does not need to be regulated by the addition of any buffers or other acidity regulating chemicals.
The invention is described in the following preferred example which represents an illustrative embodiment with which excellent practical success has been achieved.
EXAMPLE A solution consisting of 75 g. of ammonium thiocyanate and 50 g. of phenol per one liter of water was produced. A base body made of copper, which had a semiglossy nickel coating of a thickness of 0.025 mm. was immersed in the solution, which represented the galvanic bath in a corrosion resistant, plastic vat. The temperature of the bath was maintained at 35 C. The base body was connected as the anode and a metal plate made of stainless steel was used as cathode. A current density of 10 ampere/dm, was produced and the nickel coating was completely detached from the base body in about 5 minutes, whereby the base body was left smooth and in such condition that it could be provided with a galvanic coating without having first to be polished again.
I claim:
1. An aqueous electrolytic stripping bath to remove nickel, chromium, or gold coatings from copper, copper alloys, silver, zinc or titanium metal articles comprising water-soluble thiocyanate as the stripping component in an amount of 50-300 grams per liter and a phenol which is a water-soluble aromatic hydroxyl compound with at least one unsubstituted hydroxyl in the benzene ring to accelerate the stripping and reduce corrosion of the base metal in an amount of 5-80 grams per liter.
2. A bath as claimed in claim I wherein said phenol is selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, oxyhydroquinone, nitrophenol, dinitrophenol,
nitropyrocatechol, cresol, nitrocresol, thymol, nitrothymol,
xylenol and nitroxylenol.
3. A stripping bath as claimed in claim 1, wherein said phenol is cresol.
4. A stripping bath as claimed in claim 1, phenol is thymol. .1
5. A stripping bath as claimed in claim 1, phenol is xylenol.
6. A stripping bath as claimed in claim 1, phenol is nitrocresol.
wherein said wherein said wherein said 7. A stripping bath as claimed in claim 1, wherein said phenol is nitrothymol.
8. A stripping bath as claimed in claim 1, wherein said phenol is nitroxylenol.
9. A stripping bath as claimed in claim 1, wherein said phenol is nitrophenol.
10. In the stripping of coatings of nickel, chromium or gold from articles made of copper, copper alloys, silver, zinc, or titanium, the process which comprises inserting the coated ar-
Claims (9)
- 2. A bath as claimed in claim 1 wherein said phenol is selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, oxyhydroquinone, nitrophenol, dinitrophenol, nitropyrocatechol, cresol, nitrocresol, thymol, nitrothymol, xylenol and nitroxylenol.
- 3. A stripping bath as claimed in claim 1, wherein said phenol is cresol.
- 4. A stripping bath as claimed in claim 1, wherein said phenol is thymol.
- 5. A stripping bath as claimed in claim 1, wherein said phenol is xylenol.
- 6. A stripping bath as claimed in claim 1, wherein said phenol is nitrocresol.
- 7. A stripping bath as claimed in claim 1, wherein said phenol is nitrothymol.
- 8. A stripping bath as claimed in claim 1, wherein said phenol is nitroxylenol.
- 9. A stripping bath as claimed in claim 1, wherein said phenol is nitrophenol.
- 10. In the stripping of coatings of nickel, chromium or gold from articles made of copper, copper alloys, silver, zinc, or titanium, the process which comprises inserting the coated article in a stripping bath and passing electric current from said article serving as anode to a cathode, said stripping bath consisting essentially of an aqueous solution of ammonium thiocyanate as the stripping component in an amount of 50-300 grams per liter and a phenol to accelerate the stripping and reduce corrosion of the base metal in an amount of 5-80 grams per liter.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE722317 | 1968-10-15 | ||
| FR171185 | 1968-10-24 | ||
| US77134968A | 1968-10-28 | 1968-10-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3617456A true US3617456A (en) | 1971-11-02 |
Family
ID=27159288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US771349A Expired - Lifetime US3617456A (en) | 1968-10-15 | 1968-10-28 | Bath for the electrolytic stripping of galvanic coatings made of nickel, chromium or gold from base bodies made of copper, copper alloys, silver, zinc or titanium |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3617456A (en) |
| BE (1) | BE722317A (en) |
| FR (1) | FR1589902A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3793172A (en) * | 1972-09-01 | 1974-02-19 | Western Electric Co | Processes and baths for electro-stripping plated metal deposits from articles |
| US3819494A (en) * | 1973-03-29 | 1974-06-25 | Fountain Plating Co Inc | Method of removing braze |
| US4233124A (en) * | 1979-10-29 | 1980-11-11 | Oxy Metal Industries Corporation | Electrolytic stripping bath and process |
| US4264420A (en) * | 1979-10-29 | 1981-04-28 | Oxy Metal Industries Corporation | Electrolytic stripping bath and process |
| US4264419A (en) * | 1979-10-09 | 1981-04-28 | Olin Corporation | Electrochemical detinning of copper base alloys |
| DE3318598A1 (en) * | 1982-05-27 | 1983-12-01 | Occidental Chemical Corp., 48089 Warren, Mich. | BATH AND METHOD FOR THE ELECTROLYTIC REMOVAL OF COATS FROM COPPER, COPPER ALLOY OR CHROME FROM A FERROUS BASE METAL |
| CN106149042A (en) * | 2016-06-24 | 2016-11-23 | 惠州市博美环保新材料有限公司 | A kind of kirsite electrolysis stripping copper agent |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US908937A (en) * | 1908-02-18 | 1909-01-05 | Kings Norton Metal Company Ltd | Removal of metallic plating, coating, or fouling from metallic or other surfaces. |
| US2200782A (en) * | 1935-05-23 | 1940-05-14 | Metal & Thermit Corp | Detinning |
| US2463190A (en) * | 1946-07-01 | 1949-03-01 | Crowell Collier Publishing Com | Method of producing nickel powder from printing press plates and the like |
| US2596307A (en) * | 1947-11-05 | 1952-05-13 | Charles Litzenberg | Process of electrostripping electrodeposited metals |
| US2706171A (en) * | 1953-03-09 | 1955-04-12 | Enthone | Stripping chromium plating from zinc electrolytically |
| US2735810A (en) * | 1956-02-21 | Cathode |
-
1968
- 1968-10-15 BE BE722317D patent/BE722317A/xx unknown
- 1968-10-24 FR FR171185A patent/FR1589902A/fr not_active Expired
- 1968-10-28 US US771349A patent/US3617456A/en not_active Expired - Lifetime
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2735810A (en) * | 1956-02-21 | Cathode | ||
| US908937A (en) * | 1908-02-18 | 1909-01-05 | Kings Norton Metal Company Ltd | Removal of metallic plating, coating, or fouling from metallic or other surfaces. |
| US2200782A (en) * | 1935-05-23 | 1940-05-14 | Metal & Thermit Corp | Detinning |
| US2463190A (en) * | 1946-07-01 | 1949-03-01 | Crowell Collier Publishing Com | Method of producing nickel powder from printing press plates and the like |
| US2596307A (en) * | 1947-11-05 | 1952-05-13 | Charles Litzenberg | Process of electrostripping electrodeposited metals |
| US2706171A (en) * | 1953-03-09 | 1955-04-12 | Enthone | Stripping chromium plating from zinc electrolytically |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3793172A (en) * | 1972-09-01 | 1974-02-19 | Western Electric Co | Processes and baths for electro-stripping plated metal deposits from articles |
| US3819494A (en) * | 1973-03-29 | 1974-06-25 | Fountain Plating Co Inc | Method of removing braze |
| US4264419A (en) * | 1979-10-09 | 1981-04-28 | Olin Corporation | Electrochemical detinning of copper base alloys |
| US4233124A (en) * | 1979-10-29 | 1980-11-11 | Oxy Metal Industries Corporation | Electrolytic stripping bath and process |
| US4264420A (en) * | 1979-10-29 | 1981-04-28 | Oxy Metal Industries Corporation | Electrolytic stripping bath and process |
| DE3318598A1 (en) * | 1982-05-27 | 1983-12-01 | Occidental Chemical Corp., 48089 Warren, Mich. | BATH AND METHOD FOR THE ELECTROLYTIC REMOVAL OF COATS FROM COPPER, COPPER ALLOY OR CHROME FROM A FERROUS BASE METAL |
| CN106149042A (en) * | 2016-06-24 | 2016-11-23 | 惠州市博美环保新材料有限公司 | A kind of kirsite electrolysis stripping copper agent |
Also Published As
| Publication number | Publication date |
|---|---|
| FR1589902A (en) | 1970-04-06 |
| BE722317A (en) | 1969-03-14 |
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