CA1040987A - Process for stripping nickel from articles and composition utilized therein - Google Patents
Process for stripping nickel from articles and composition utilized thereinInfo
- Publication number
- CA1040987A CA1040987A CA201,047A CA201047A CA1040987A CA 1040987 A CA1040987 A CA 1040987A CA 201047 A CA201047 A CA 201047A CA 1040987 A CA1040987 A CA 1040987A
- Authority
- CA
- Canada
- Prior art keywords
- chloride
- tellurium
- ions
- stripping
- selenium
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/44—Compositions for etching metallic material from a metallic material substrate of different composition
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Chemically Coating (AREA)
Abstract
PROCESS FOR STRIPPING NICKEL
FROM ARTICLES
AND
COMPOSITION UTILIZED THEREIN
ABSTRACT OF THE DISCLOSURE
The present invention is directed to the chemical removal of adherent nickel deposits on plating racks and the like employing a composition which contains therein nitric acid and sources of chloride, copper and tellurium or selen-ium ions and to a process for stripping such unwanted deposits from electroplating apparatus without noticeable damage to the base metal and at speeds not normally obtainable with prior art compositions and methods.
FROM ARTICLES
AND
COMPOSITION UTILIZED THEREIN
ABSTRACT OF THE DISCLOSURE
The present invention is directed to the chemical removal of adherent nickel deposits on plating racks and the like employing a composition which contains therein nitric acid and sources of chloride, copper and tellurium or selen-ium ions and to a process for stripping such unwanted deposits from electroplating apparatus without noticeable damage to the base metal and at speeds not normally obtainable with prior art compositions and methods.
Description
1(~4~39~7 , BACKGROUND OF THE INVENTION
It is known in the art to which this invention pertains that nickel and related metallic coatings on the contact tips of the plating racks of electroplating apparatus can be removed by either mechanical means or chemical techniques. In themechanical approach it has been conventional to use a hammer or like tool means to shatter the unwanted nickel deposit on the contact tips, and while this treatment is generally effective, it suffers from the disadvantages of being time-consuming and may ultimately result in damage to the metal base. Thèn too, some plating racks contain several hundred individual tips, so that mechanical removal of the unwanted coatings thereon leads to substantial labor costs.
Chemical methods for dissolution of the nickel deposits on stainless steel racks have generally employed nitric acid, and while this approach represents an improvement over the hammer method, the use of nitric acid by itself is tedious since - ;
nickel is only slowly attacked by this acid. It has accordingly - -been customary to add a catalyst such as a chloride ion, but this substance in the presence of strong nitric acid forms nitrosyl chloride which is a gas at tèmperatures above about-5.5C., and accordingly, its benefit to the stripping solution is soon lost by volatilization. The addition of other ions to the solution has also been proposed, as the iodate ion disclosed in Patent No. ! ' 3,399,143: however, following these teachings does not obviate - -the objection of relatively slow stripping speeds, and may under particular conditions cause damage to the stainless steel contact tips.
,,, . ,,, ,, , ; ,,, . :; ,, ;, ,., .. ;. ,, ., ,,", ; .,~,. ,, .. ,.,, , , ., ........ , .':
1()4~87 SUMMARY OF THE INVENTION
The invention is directed to a composition for strip-ping accumulated nickel deposits from plating apparatus and the like, which comprises nitric acid and sources of chloride, copper and tellurium or selenium ions, said chloride ion being present in concentrations of about 0.01 to 0.5 M and said tellurium or selenium ions being present in small but effective amounts sufficient to accelerate the stripping rate without noticeable deleterious effects upon the plating apparatus.
The invention also relates to a method of stripping nickel deposits from articles by immersing them in a concentra-ted nitric acid solution containing a chloride catalyst, which comprises adding to said solution a small but effective amount of a selenite or tellurite compound capable of providing sele-nium or tellurium ions in the solution.
The instant invention is particularly directed to a novel composition for removing nickel and generally similar unwanted deposits from plating racks and like articles and to a --process for utilizing said composition, the formulation conceived by applicant comprising about 4.5 to 14.5 moles/liter of 42 Be. nitric acid, a chloride ion in the amount of 0.01 to 0.5 moles/liter, a copper ion in the amount of about 0.01 to 0.5 preferably 0.01 to 0.1 moles/liter,and a source of tellurium or selenium ions in the amount of approximately 0.005 to 0.2 moles/
liter. Preferably,the molar ratio of tellurium or selenium ions to chloride ions is in the general range of about one to three.
While applicant does not wish to be bound by a partic-ular theory, it would appear from work performed to date that tellurium or selenium when admixed with the other constituents of the solution herein disclosed in the general molar ratios above set forth possesses film-forming capabilities. This is
It is known in the art to which this invention pertains that nickel and related metallic coatings on the contact tips of the plating racks of electroplating apparatus can be removed by either mechanical means or chemical techniques. In themechanical approach it has been conventional to use a hammer or like tool means to shatter the unwanted nickel deposit on the contact tips, and while this treatment is generally effective, it suffers from the disadvantages of being time-consuming and may ultimately result in damage to the metal base. Thèn too, some plating racks contain several hundred individual tips, so that mechanical removal of the unwanted coatings thereon leads to substantial labor costs.
Chemical methods for dissolution of the nickel deposits on stainless steel racks have generally employed nitric acid, and while this approach represents an improvement over the hammer method, the use of nitric acid by itself is tedious since - ;
nickel is only slowly attacked by this acid. It has accordingly - -been customary to add a catalyst such as a chloride ion, but this substance in the presence of strong nitric acid forms nitrosyl chloride which is a gas at tèmperatures above about-5.5C., and accordingly, its benefit to the stripping solution is soon lost by volatilization. The addition of other ions to the solution has also been proposed, as the iodate ion disclosed in Patent No. ! ' 3,399,143: however, following these teachings does not obviate - -the objection of relatively slow stripping speeds, and may under particular conditions cause damage to the stainless steel contact tips.
,,, . ,,, ,, , ; ,,, . :; ,, ;, ,., .. ;. ,, ., ,,", ; .,~,. ,, .. ,.,, , , ., ........ , .':
1()4~87 SUMMARY OF THE INVENTION
The invention is directed to a composition for strip-ping accumulated nickel deposits from plating apparatus and the like, which comprises nitric acid and sources of chloride, copper and tellurium or selenium ions, said chloride ion being present in concentrations of about 0.01 to 0.5 M and said tellurium or selenium ions being present in small but effective amounts sufficient to accelerate the stripping rate without noticeable deleterious effects upon the plating apparatus.
The invention also relates to a method of stripping nickel deposits from articles by immersing them in a concentra-ted nitric acid solution containing a chloride catalyst, which comprises adding to said solution a small but effective amount of a selenite or tellurite compound capable of providing sele-nium or tellurium ions in the solution.
The instant invention is particularly directed to a novel composition for removing nickel and generally similar unwanted deposits from plating racks and like articles and to a --process for utilizing said composition, the formulation conceived by applicant comprising about 4.5 to 14.5 moles/liter of 42 Be. nitric acid, a chloride ion in the amount of 0.01 to 0.5 moles/liter, a copper ion in the amount of about 0.01 to 0.5 preferably 0.01 to 0.1 moles/liter,and a source of tellurium or selenium ions in the amount of approximately 0.005 to 0.2 moles/
liter. Preferably,the molar ratio of tellurium or selenium ions to chloride ions is in the general range of about one to three.
While applicant does not wish to be bound by a partic-ular theory, it would appear from work performed to date that tellurium or selenium when admixed with the other constituents of the solution herein disclosed in the general molar ratios above set forth possesses film-forming capabilities. This is
-2-: ,:
. , . ., . " ~, . . .
10~987 perceptible to the naked eye when an examination is made of a stainless steel substrate, and is the apparent reason why there is no noticeable attack upon the surface being stripped and also why unwanted nickel deposits can be removed at speeds approximate-ly 30% faster than commercially available plating solutions.
The invention also relates to an aqueous solution for stripping accumulated nickel deposits from plating apparatus, which contains therein about 2 to 10 grams per liter of tellurium or selenium dioxide, 600 to 850 grams per liter of nitric acid, 2 to 20 grams per liter of CuSO4.5H2O, and 3.5 to 35.5 grams per liter of a source of chloride ions.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The stripping solution employed in the practice of this invention may be prepared by either one of two procedures.
First, there can be initially formed a sodium or potassium salt of tellurium dioxide (tellurous acid anhydride) or selenium dioxide (selenous acid anhydride) by mixing approximately 15 grams of Te 2 or Se 2 with about 10 to 12 ml. of NaOH or KOH, ~ -diluting the solution obtained to about 150 ml, and thereafter -filtering ~ -";'-`''' '''.' - 2a - -.
9~37 out the precipitate. A preferred concentration for the hydro-xide used is about 50%. The sodium or potassium tellurite or selenite obtained is then combined with measured quantities of nitric acid, cupric sulfate and sodium chloride to provide the novel stripping solution of this invention.
A second procedure for formulating the stripping solu-tion is to directly admix predetermined amounts of Te 2 or SeO2 HN03. CuS04 . SH20, and NaCl. This procedure is somewhat less expensive than going through the first approach, however, at times it may be found that combining the TeO2 or SeO2 directly with HN03 produces a somewhat violent reaction. The first mentioned procedure is accordingly preferred at the present time.
The invention will now be more fully described wlth reference to the following examples, which were run at a solution temperature of approximately 40C.
E~AMPLE I
A solution was made up of 500 mil. HN0 , 5.7 g. CuS0 .
SH2o, 3.3 g. NaCl and 3.0 g. FeC13 , which were diluted to 1 liter. A stainless steel part having a nickel deposit thereon of about one mil in thickness was immersed therein, and it took about 87 seconds before the deposit was removed.
EX~Ml?LE I I
There was formulated a solution containing 500 ml. ~ -HN03 , 5.7 g. CuS04. SH20, 3.3 g. NaCl, 2.0 g. of a commercially available strip aid (composition unknown), and this mixture -diluted to 1 liter. It took about 141 seconds to remove a one mil thick nickel deposit from a stainless steel part. -EXAMPLE I I I : .
A solution was made up of 500 ml. HN03, 5.7 g. CuS04, 5H2O, 3.3 g. NaCl and 1.5 g. Na2TeO3, which were diluted to 1 liter. It only took 33 seconds to strip a one mil nickel deposit from a stainless steel part.
9~7 T~ M P T . F~ T t7 The procedure of Example III was followed except that Na2SeO3 was substituted for the Na2TeO3. The same thickness deposit was removed in 35 seconds.
`' EXAMPLE V
The procedure of Example III was again followed, except that 1.5 g. NaF was used in place of the Na2TeO3. A nickel de~osi~
o the same thickness took 110 seconds to be removed from a stain-l~ss steel part. -EXAMPLE VI
.
Therè was formulated a stripping solution containlng 500 ml. HNO3, 5.7 g. CuSO4-5H2O, 3.3 g. NaCl, 1 g.KBrO3 and 0.3 ~. KIO3 which was diluted to 1 liter. A one mil nickel deposit was removed from a stainless steel part in 100 seconds. - -EXAMPLE VII
A solution was made up of 500 ml. HNO3, 5.7 g. CuSO4 5~120,
. , . ., . " ~, . . .
10~987 perceptible to the naked eye when an examination is made of a stainless steel substrate, and is the apparent reason why there is no noticeable attack upon the surface being stripped and also why unwanted nickel deposits can be removed at speeds approximate-ly 30% faster than commercially available plating solutions.
The invention also relates to an aqueous solution for stripping accumulated nickel deposits from plating apparatus, which contains therein about 2 to 10 grams per liter of tellurium or selenium dioxide, 600 to 850 grams per liter of nitric acid, 2 to 20 grams per liter of CuSO4.5H2O, and 3.5 to 35.5 grams per liter of a source of chloride ions.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The stripping solution employed in the practice of this invention may be prepared by either one of two procedures.
First, there can be initially formed a sodium or potassium salt of tellurium dioxide (tellurous acid anhydride) or selenium dioxide (selenous acid anhydride) by mixing approximately 15 grams of Te 2 or Se 2 with about 10 to 12 ml. of NaOH or KOH, ~ -diluting the solution obtained to about 150 ml, and thereafter -filtering ~ -";'-`''' '''.' - 2a - -.
9~37 out the precipitate. A preferred concentration for the hydro-xide used is about 50%. The sodium or potassium tellurite or selenite obtained is then combined with measured quantities of nitric acid, cupric sulfate and sodium chloride to provide the novel stripping solution of this invention.
A second procedure for formulating the stripping solu-tion is to directly admix predetermined amounts of Te 2 or SeO2 HN03. CuS04 . SH20, and NaCl. This procedure is somewhat less expensive than going through the first approach, however, at times it may be found that combining the TeO2 or SeO2 directly with HN03 produces a somewhat violent reaction. The first mentioned procedure is accordingly preferred at the present time.
The invention will now be more fully described wlth reference to the following examples, which were run at a solution temperature of approximately 40C.
E~AMPLE I
A solution was made up of 500 mil. HN0 , 5.7 g. CuS0 .
SH2o, 3.3 g. NaCl and 3.0 g. FeC13 , which were diluted to 1 liter. A stainless steel part having a nickel deposit thereon of about one mil in thickness was immersed therein, and it took about 87 seconds before the deposit was removed.
EX~Ml?LE I I
There was formulated a solution containing 500 ml. ~ -HN03 , 5.7 g. CuS04. SH20, 3.3 g. NaCl, 2.0 g. of a commercially available strip aid (composition unknown), and this mixture -diluted to 1 liter. It took about 141 seconds to remove a one mil thick nickel deposit from a stainless steel part. -EXAMPLE I I I : .
A solution was made up of 500 ml. HN03, 5.7 g. CuS04, 5H2O, 3.3 g. NaCl and 1.5 g. Na2TeO3, which were diluted to 1 liter. It only took 33 seconds to strip a one mil nickel deposit from a stainless steel part.
9~7 T~ M P T . F~ T t7 The procedure of Example III was followed except that Na2SeO3 was substituted for the Na2TeO3. The same thickness deposit was removed in 35 seconds.
`' EXAMPLE V
The procedure of Example III was again followed, except that 1.5 g. NaF was used in place of the Na2TeO3. A nickel de~osi~
o the same thickness took 110 seconds to be removed from a stain-l~ss steel part. -EXAMPLE VI
.
Therè was formulated a stripping solution containlng 500 ml. HNO3, 5.7 g. CuSO4-5H2O, 3.3 g. NaCl, 1 g.KBrO3 and 0.3 ~. KIO3 which was diluted to 1 liter. A one mil nickel deposit was removed from a stainless steel part in 100 seconds. - -EXAMPLE VII
A solution was made up of 500 ml. HNO3, 5.7 g. CuSO4 5~120,
3.3 g. NaCl and 1 ml. bromine, the mixture being diluted to 1 liter.
A one mil nickel deposit was stripped from a stainless steei part in 94 seconds.
EXAMPLE VIII
There was formulated a stripping solution containing 500 ml. HNO3, 5.7 g. CuSO4 5H2O, 3.3 g. NaCl, and 10 ml. Na2TeO3 -~
solution prepared as earlier described, and this mixture was diluted to 1 liter. A nickel deposit of a thickness of one mil w2S stripped in only 58 seconds. ~ :
EXAMPLE IX ~
~ solution was prepared as in Example VIII, but the ~ ~;
amount of Na2TeO3 solution was increased to 20 ml. A deposi~ , of the same thickness was removed in only 33 seconds.
~', -' , ' ,
A one mil nickel deposit was stripped from a stainless steei part in 94 seconds.
EXAMPLE VIII
There was formulated a stripping solution containing 500 ml. HNO3, 5.7 g. CuSO4 5H2O, 3.3 g. NaCl, and 10 ml. Na2TeO3 -~
solution prepared as earlier described, and this mixture was diluted to 1 liter. A nickel deposit of a thickness of one mil w2S stripped in only 58 seconds. ~ :
EXAMPLE IX ~
~ solution was prepared as in Example VIII, but the ~ ~;
amount of Na2TeO3 solution was increased to 20 ml. A deposi~ , of the same thickness was removed in only 33 seconds.
~', -' , ' ,
-4-'.' ' ' 104~3987 EX~PLE X
There was formulated a stripping ~olution containing 2 g/l TeO2 , 600 g/l HNO3 , 5.? g/l CuSO4.5lJ2O and 3.3 g/l NaCl. An unwanted nickel deposit one mil thick was stripped S from a stainless steel part in 2? seconds, which is about 30%
faster than commerically available strippers.
In the exemplary formulations set forth above, potassium hydroxide can readily be subst.itu'ed for sodium hydroxide;
potassium, manganese or cupric chloride can be used in place of sodium chloride; and cupric nitrate or chloride axe substituents for cupric sulfate. Further, if desired, a portion of the nitric acid may be replaced by an equivalent (i.e., acid equivalent) amount of sulfurric acid, thereb~ satisfying the hydrogen ion requirement by a less expensive acid~
Various modifications i,~ the compositions of this invention have been pointed out herein, and these and other changes can of course be effected without departing from the spirit of the invention of the scope of the subjoined claims.
. "" . ' .
.~' ' ,' '.; .
.-. .
.~;
. ~ -.. . . . . . . . . . ... . . . . .. . ... .. . . .
There was formulated a stripping ~olution containing 2 g/l TeO2 , 600 g/l HNO3 , 5.? g/l CuSO4.5lJ2O and 3.3 g/l NaCl. An unwanted nickel deposit one mil thick was stripped S from a stainless steel part in 2? seconds, which is about 30%
faster than commerically available strippers.
In the exemplary formulations set forth above, potassium hydroxide can readily be subst.itu'ed for sodium hydroxide;
potassium, manganese or cupric chloride can be used in place of sodium chloride; and cupric nitrate or chloride axe substituents for cupric sulfate. Further, if desired, a portion of the nitric acid may be replaced by an equivalent (i.e., acid equivalent) amount of sulfurric acid, thereb~ satisfying the hydrogen ion requirement by a less expensive acid~
Various modifications i,~ the compositions of this invention have been pointed out herein, and these and other changes can of course be effected without departing from the spirit of the invention of the scope of the subjoined claims.
. "" . ' .
.~' ' ,' '.; .
.-. .
.~;
. ~ -.. . . . . . . . . . ... . . . . .. . ... .. . . .
Claims (8)
1. A composition for stripping accumulated nickel deposits from plating apparatus and the like, which comprises nitric acid and sources of chloride, copper and tellurium or selenium ions, said chloride ion being present in concentrations of about 0.01 to 0.5 M and said tellurium or selenium ions being present in small but effective amounts sufficient to accelerate the stripping rate without noticeable deleterious effects upon the plating apparatus.
2. A composition as defined in Claim 1, in which the tellurium or selenium ions are present in concentrations of about 0.005 to 0.2 M.
3. A composition as defined in Claim 1, in which the copper ion is present in concentrations of about 0.01 to 0.5 M.
4. A composition as defined in Claim 1, in which the nitric acid is approximately 42 Be. and is present in an amount of about 4.5 to 14.5 M.
5. An aqueous solution for stripping accumulated nickel deposits from plating apparatus, which contains therein about 2 to 10 grams per liter of tellurium or selenium dioxide, 600 to 850 grams per liter of nitric acid, 2 to 20 grams per liter of CuSO4.5H2O, and 3.5 to 35.5 grams per liter of a source of chloride ions.
6. An aqueous solution as defined in Claim 1, in which the source of chloride ions is selected from the group consisting of sodium chloride, potassium chloride, manganese chloride and cupric chloride.
7. In a method of stripping nickel deposits from articles by immersing them in a concentrated nitric acid solution contain-ing a chloride catalyst, the improvement which comprises adding to said solution a small but effective amount of a selenite or tellurite compound capable of providing selenium or tellurium ions in the solution.
8. A stripping method as defined in Claim 7, in which the selenium or tellurium ions are present in concentrations of about 0.005 to 0.2 M.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US00370889A US3856694A (en) | 1973-06-18 | 1973-06-18 | Process for stripping nickel from articles and composition utilized therein |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1040987A true CA1040987A (en) | 1978-10-24 |
Family
ID=23461605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA201,047A Expired CA1040987A (en) | 1973-06-18 | 1974-05-28 | Process for stripping nickel from articles and composition utilized therein |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US3856694A (en) |
| JP (1) | JPS5647263B2 (en) |
| BR (1) | BR7404948D0 (en) |
| CA (1) | CA1040987A (en) |
| DE (1) | DE2428380C3 (en) |
| ES (1) | ES427394A1 (en) |
| FR (1) | FR2233418A1 (en) |
| GB (1) | GB1475327A (en) |
| IT (1) | IT1013479B (en) |
| NL (1) | NL7407382A (en) |
| ZA (1) | ZA743138B (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2448526C3 (en) * | 1974-10-11 | 1978-03-30 | Audi Nsu Auto Union Ag, 7107 Neckarsulm | Process for the electroless removal of a nickel layer from nickel-coated objects made of light metal |
| US4042451A (en) * | 1975-08-05 | 1977-08-16 | M&T Chemicals Inc. | Selected stripping of nickel-iron alloys from ferrous substrates |
| US4274908A (en) * | 1978-08-15 | 1981-06-23 | United Technologies Corporation | Cyanide free solution and process for removing gold-nickel braze |
| US4244833A (en) * | 1979-11-15 | 1981-01-13 | Oxy Metal Industries Corporation | Composition and process for chemically stripping metallic deposits |
| US4353780A (en) * | 1980-10-01 | 1982-10-12 | United Technologies Corporation | Chemical milling of high tungsten content superalloys |
| DK395481A (en) * | 1980-10-01 | 1982-04-02 | United Technologies Corp | METHOD AND METHOD FOR PROCESSING SUBSTANCES OF A NICKEL-ALUMINUM ALLOY |
| US4339282A (en) * | 1981-06-03 | 1982-07-13 | United Technologies Corporation | Method and composition for removing aluminide coatings from nickel superalloys |
| CA1209886A (en) * | 1982-01-11 | 1986-08-19 | Thomas W. Bleeks | Peroxide selective stripping compositions and method |
| US4746369A (en) * | 1982-01-11 | 1988-05-24 | Enthone, Incorporated | Peroxide selective stripping compositions and method |
| US4608091A (en) * | 1982-01-11 | 1986-08-26 | Enthone, Incorporated | Peroxide selective stripping compositions and method |
| US4554049A (en) * | 1984-06-07 | 1985-11-19 | Enthone, Incorporated | Selective nickel stripping compositions and method of stripping |
| CH674851A5 (en) * | 1987-12-01 | 1990-07-31 | Bbc Brown Boveri & Cie | |
| CA2090349C (en) * | 1992-03-04 | 1999-08-17 | John L. Cordani | Composition and method for stripping tin or tin-lead alloy from copper surfaces |
| US6642199B2 (en) | 2001-04-19 | 2003-11-04 | Hubbard-Hall, Inc. | Composition for stripping nickel from substrates and process |
| CA2808981A1 (en) * | 2013-03-05 | 2014-09-05 | Sherritt International Corporation | Method of recovering metals while mitigating corrosion |
| US11460778B2 (en) * | 2018-04-12 | 2022-10-04 | Versum Materials Us, Llc | Photoresist stripper |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3197341A (en) * | 1961-06-19 | 1965-07-27 | Rohr Corp | Method and composition for descaling stainless steels and related alloys |
| US3365401A (en) * | 1967-03-14 | 1968-01-23 | Enthone | Immersion type nickel stripper |
| US3553016A (en) * | 1967-06-02 | 1971-01-05 | Lithcote Corp | Method and composition for treating stainless steel |
| US3399143A (en) * | 1967-08-02 | 1968-08-27 | Macdermid Inc | Method of stripping nickel from articles and the composition used therein |
| US3709824A (en) * | 1971-01-07 | 1973-01-09 | Nippon Soda Co | Method and composition for chemical polishing of stainless steel surfaces |
| US3717520A (en) * | 1971-02-09 | 1973-02-20 | Enthone | Composition and method for selectively stripping nickel and/or copper |
-
1973
- 1973-06-18 US US00370889A patent/US3856694A/en not_active Expired - Lifetime
- 1973-06-18 ES ES427394A patent/ES427394A1/en not_active Expired
-
1974
- 1974-05-16 ZA ZA00743138A patent/ZA743138B/en unknown
- 1974-05-28 CA CA201,047A patent/CA1040987A/en not_active Expired
- 1974-05-31 NL NL7407382A patent/NL7407382A/xx not_active Application Discontinuation
- 1974-06-12 DE DE2428380A patent/DE2428380C3/en not_active Expired
- 1974-06-14 IT IT51539/74A patent/IT1013479B/en active
- 1974-06-15 JP JP6864374A patent/JPS5647263B2/ja not_active Expired
- 1974-06-17 BR BR4948/74A patent/BR7404948D0/en unknown
- 1974-06-17 GB GB2674074A patent/GB1475327A/en not_active Expired
- 1974-06-18 FR FR7421109A patent/FR2233418A1/fr not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| BR7404948D0 (en) | 1975-01-07 |
| IT1013479B (en) | 1977-03-30 |
| AU6905174A (en) | 1975-11-20 |
| DE2428380B2 (en) | 1978-10-19 |
| NL7407382A (en) | 1974-12-20 |
| FR2233418A1 (en) | 1975-01-10 |
| US3856694A (en) | 1974-12-24 |
| ES427394A1 (en) | 1977-02-01 |
| DE2428380C3 (en) | 1979-06-07 |
| JPS5647263B2 (en) | 1981-11-09 |
| DE2428380A1 (en) | 1975-01-09 |
| ZA743138B (en) | 1975-06-25 |
| JPS5036321A (en) | 1975-04-05 |
| GB1475327A (en) | 1977-06-01 |
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