US2954289A - Dissolving of nickel-phosphorous alloys - Google Patents
Dissolving of nickel-phosphorous alloys Download PDFInfo
- Publication number
- US2954289A US2954289A US639630A US63963057A US2954289A US 2954289 A US2954289 A US 2954289A US 639630 A US639630 A US 639630A US 63963057 A US63963057 A US 63963057A US 2954289 A US2954289 A US 2954289A
- Authority
- US
- United States
- Prior art keywords
- mole percent
- nickel
- stripping
- phosphorous alloy
- nitric acid
- 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
- 229910045601 alloy Inorganic materials 0.000 title claims description 26
- 239000000956 alloy Substances 0.000 title claims description 26
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 17
- 238000007747 plating Methods 0.000 claims description 17
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 239000010953 base metal Substances 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 18
- 239000000203 mixture Substances 0.000 description 16
- 239000000243 solution Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 229910052759 nickel Inorganic materials 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 7
- 229910017604 nitric acid Inorganic materials 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- -1 cuprous Chemical compound 0.000 description 5
- 238000000576 coating method Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 229910000640 Fe alloy Inorganic materials 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 150000007513 acids Chemical class 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 241001427367 Gardena Species 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000011260 aqueous acid Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
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
Definitions
- This invention relates to the process of stripping relatively thin metal coatings from a base metal structure and particularly to a process and composition for stripping nickel-phosphorous alloy or chemical nickel plating from the metal upon which it has been deposited.
- Nickel-phosphorous alloy plating or chemical nickel plating is a process well known in the art for depositing upon ferrous, cuprous, aluminum and certain other metals and alloys a coating of an alloy having a composition of from 85 to 99.9 percent nickel and from 0.1 to 15 percent phosphorus without the use of an electrical cur rent.
- nickel Prior to the advent of this process, nickel had been plated or deposited by electrolytic methods and the nickel thus deposited was substantially pure nickel.
- To strip the thus conventionally deposited nickel from the steel specimens or body upon which it had been plated was accomplished by a reverse electrolytic process, using sulfuric acid and similar solutions, by the use of fuming nitric acid as described in US. Patent No. 2,200,486 or bythe use of an alkaline solution such as suggested in US.
- Patent No. 2,649,361 The foregoing three methods for removing or stripping conventional electro-plated nickel however, have been found unsatisfactory for the stripping or removal of nickel-phosphorous alloy plating inasmuch as the deposit, as noted above, is of a substantially different composition.
- the use of the reverse electrolytic process results in pitting of the base material particularly in the deep recesses.
- the other two methods of stripping noted above were unsuccessful in stripping nickel-phosphorous alloy plating since the deposited alloy did not respond as electrolytically deposited nickel would respond and in the first case the solution did not attack the alloy and in the second the alloy was merely made porous.
- This invention contemplates a composition which has proved effective in shipping nickel-phosphorous alloy coatings from ferrous and aluminum alloys and a process of using said composition for the successful stripping of said plating.
- This invention contemplates formulations using nitric acid concentrations ranging from 72.0 mole percent to 9.0 mole percent and hydrofluoric acid concentrations ranging from 50.3 mole percent to 0.0 mole percent and water content ranging from 28.0 mole percent to 58.6 mole percent.
- Formulations composed of acids containing nitrate ions, aqueous acid solutions of fluoride ions or any salt containing the fluoride ion are also considered to be within the scope of this invention.
- Example 1 A mixture of 68.4 mole percent nitric acid, 2.9 mole percent hydrofluoric acid and 28.7 mole percent water was placed in a tank lined with polyethylene in clean and dry condition and a clean, dry nickel-phosphorous alloy plated steel specimen was immersed in the solution. After one and one half hours immersion, the specimen was removed, washed, dried and observed to have a light grey metallic appearance of exposed basis metal. A copper sulphate test showed positive results of complete stripping. Visual inspection under a 3 power glass showed no attack of the basis metal. The thickness of the specimen before immersion was 0.045 inch and after immersion was 0.042 inch, indicating that the stripper had removed 1.5 mils of nickel-phosphorous alloy per side.
- Example 2 A steel specimen immersed in a solution of 64.5 mole percent nitric acid, 6.0 mole percent hydrofluoric acid and 29.5 mole percent water for a period of one hour was completely stripped of its 0.002 inch nickel-phosphorous alloy coating. Tests and inspection described above showed complete plating removal and no attack of the basis metal.
- Example 3 The experiments of Examples 1 and 2 were repeated but with 59.0 mole percent nitric acid and 10.8 mole percent hydrofluoric acid and 30.2 mole percent water for a period of 30 minutes. The decrease in thickness was observed to be 1.5 mil per side and the specimen was tested and shown to be completely stripped with no visible attack of the basis metal.
- Example 4 In this example the solution consisted of nitric acid 41.5 mole percent, hydrofluoric acid, 24.5 mole percent and water, 34.0 mole percent. In a time of 20-25 minutes a decrease in thickness of 1.6 mil per side was observed and the above tests revealed complete stripping without visible attack to the basis metal. This solution appeared to be near optimum.
- the stripping solution will cause an excessive increase in the temperature.
- the temperature For quality stripping, tree of. surface etching, the temperature must be controlled at a maximum of 150 Fahrenheit. No minimum temperature has been established as temperature reduction will decrease the stripping rate but in no other way detrimentally afiects the stripping efficiency.
- the method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal including the step of: immersing the workpiece in a stripping bath containing from about 41.5 mole percent to about 68.4 mole percent fuming nitric acid, from about 2.9 mole percent to about 24.5 mole percent hydrofluoric acid, and the remainder water.
- the method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal including the step of: immersing the workpiece in a stripping bath containing about 41.5 mole percent 4 fuming nitric acid, about 24.5 mole percent hydrofluoric acid, and the remainder water.
- the method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal including the step of: immersing the workpiece in a stripping bath maintained at a temperature no greater than about Fahrenheit and containing from about 4L5 mole percent to about 68.4 mole percent fuming nitric acid, from about 2.9 mole percent to about 24.5 mole percent hydrofluoric acid, and the remainder water.
- the method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal including the step of: immersing the workpiece in a stripping bath maintained at a temperature no greater than about 150 Fahrenheit and containing about 41.5 mole percent fuming nitric acid, about 24.5 mole percent hydrofluoric acid, and the remainder water.
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- 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)
Description
United States Patent "ice DISSOLVING 0F NICKELPHQSIHUROUS ALLUYS Bert J. Sherwood, Los Angeles, and William R. Hoyt, Gardena, Calif., assignors to Chemplate Corp., Los Angeles, Calif., a corporation of California No Drawing. Filed Feb. 12, 1957, Ser. No. 639,630
4 Claims. (CI. 75-97) This invention relates to the process of stripping relatively thin metal coatings from a base metal structure and particularly to a process and composition for stripping nickel-phosphorous alloy or chemical nickel plating from the metal upon which it has been deposited.
Nickel-phosphorous alloy plating or chemical nickel plating is a process well known in the art for depositing upon ferrous, cuprous, aluminum and certain other metals and alloys a coating of an alloy having a composition of from 85 to 99.9 percent nickel and from 0.1 to 15 percent phosphorus without the use of an electrical cur rent. Prior to the advent of this process, nickel had been plated or deposited by electrolytic methods and the nickel thus deposited was substantially pure nickel. To strip the thus conventionally deposited nickel from the steel specimens or body upon which it had been plated, was accomplished by a reverse electrolytic process, using sulfuric acid and similar solutions, by the use of fuming nitric acid as described in US. Patent No. 2,200,486 or bythe use of an alkaline solution such as suggested in US. Patent No. 2,649,361. The foregoing three methods for removing or stripping conventional electro-plated nickel however, have been found unsatisfactory for the stripping or removal of nickel-phosphorous alloy plating inasmuch as the deposit, as noted above, is of a substantially different composition. The use of the reverse electrolytic process results in pitting of the base material particularly in the deep recesses. The other two methods of stripping noted above were unsuccessful in stripping nickel-phosphorous alloy plating since the deposited alloy did not respond as electrolytically deposited nickel would respond and in the first case the solution did not attack the alloy and in the second the alloy was merely made porous.
This invention contemplates a composition which has proved effective in shipping nickel-phosphorous alloy coatings from ferrous and aluminum alloys and a process of using said composition for the successful stripping of said plating.
It is therefore an object of thisinvention to provide an improved nickel-phosphorous alloy stripping composition.
It is another object of this invention to provide an improved nickel-phosphorous alloy stripping composition which attacks nickel-phosphorous alloy plating but does not attack base metals upon which said plating may be deposited such as ferrous alloys and aluminum alloys.
It is another object of this invention to provide an improved method of stripping nickel-phosphorous alloy plating from the metal upon which it has been deposited. It is another object of this invention to provide a method and composition for stripping nickel-phosphorous alloy plating from ferrous and aluminum alloys which does not attack or pit the base metal.
Other objects will become apparent from the following specifications:
The preferred composition of the stripper described in this inventioaiaamiature 9t acids s i s of t s nitric acid (specific gravity 1.49-1.50) 41.5 mole percent and aqueous hydrofluoric acid solution 24.5 mole per- 655F511 water 34.0'fiiblpfiiehti lhe stripping is accompli s hed by immersion of the nickel-phosphorous alloy plated specimen in the above mixture at ambient temperature. The time required to strip a given thickness of nickel-phosphorous alloy plating varies with the relative concentrations of the above acids and extremely wide deviations from the above basic formulation may be made without departing from the scope of this invention.
This invention contemplates formulations using nitric acid concentrations ranging from 72.0 mole percent to 9.0 mole percent and hydrofluoric acid concentrations ranging from 50.3 mole percent to 0.0 mole percent and water content ranging from 28.0 mole percent to 58.6 mole percent. Formulations composed of acids containing nitrate ions, aqueous acid solutions of fluoride ions or any salt containing the fluoride ion are also considered to be within the scope of this invention.
The following examples illustrate the effect of varying the relative concentrations of nitric acid and hydrofluoric acid in the above compositions:
Example 1 A mixture of 68.4 mole percent nitric acid, 2.9 mole percent hydrofluoric acid and 28.7 mole percent water was placed in a tank lined with polyethylene in clean and dry condition and a clean, dry nickel-phosphorous alloy plated steel specimen was immersed in the solution. After one and one half hours immersion, the specimen was removed, washed, dried and observed to have a light grey metallic appearance of exposed basis metal. A copper sulphate test showed positive results of complete stripping. Visual inspection under a 3 power glass showed no attack of the basis metal. The thickness of the specimen before immersion was 0.045 inch and after immersion was 0.042 inch, indicating that the stripper had removed 1.5 mils of nickel-phosphorous alloy per side.
Example 2 A steel specimen immersed in a solution of 64.5 mole percent nitric acid, 6.0 mole percent hydrofluoric acid and 29.5 mole percent water for a period of one hour was completely stripped of its 0.002 inch nickel-phosphorous alloy coating. Tests and inspection described above showed complete plating removal and no attack of the basis metal.
Example 3 The experiments of Examples 1 and 2 were repeated but with 59.0 mole percent nitric acid and 10.8 mole percent hydrofluoric acid and 30.2 mole percent water for a period of 30 minutes. The decrease in thickness was observed to be 1.5 mil per side and the specimen was tested and shown to be completely stripped with no visible attack of the basis metal.
Example 4 In this example the solution consisted of nitric acid 41.5 mole percent, hydrofluoric acid, 24.5 mole percent and water, 34.0 mole percent. In a time of 20-25 minutes a decrease in thickness of 1.6 mil per side was observed and the above tests revealed complete stripping without visible attack to the basis metal. This solution appeared to be near optimum.
In the foregoing it was observed that while solution No. 4 appeared to be optimum, a fairly wide variation in composition and proportions of constituents involved can be tolerated without seriously affecting the quantity of the stripping accomplished. It was observed that it is highly important that the tanks be lined with inert materials such as polyethylene and that the parts to be stripped be extremely clean of grease, dirt and moisture. Because of the evolution of gas during the chemical stripping, work must be held in such a manner as to permit the gases to escape from any recesses.
Processing of large volumes of work through. the stripping solution will cause an excessive increase in the temperature. For quality stripping, tree of. surface etching, the temperature must be controlled at a maximum of 150 Fahrenheit. No minimum temperature has been established as temperature reduction will decrease the stripping rate but in no other way detrimentally afiects the stripping efficiency. I Although the invention has been described and illustrated in detail, the same is to be understood to be by way' of illustration and example only, the spirit and scope of the invention being limited only by the terms of the appended claims.
We claim:
1. The method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal, including the step of: immersing the workpiece in a stripping bath containing from about 41.5 mole percent to about 68.4 mole percent fuming nitric acid, from about 2.9 mole percent to about 24.5 mole percent hydrofluoric acid, and the remainder water.
2. The method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal, including the step of: immersing the workpiece in a stripping bath containing about 41.5 mole percent 4 fuming nitric acid, about 24.5 mole percent hydrofluoric acid, and the remainder water.
3. The method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal, including the step of: immersing the workpiece in a stripping bath maintained at a temperature no greater than about Fahrenheit and containing from about 4L5 mole percent to about 68.4 mole percent fuming nitric acid, from about 2.9 mole percent to about 24.5 mole percent hydrofluoric acid, and the remainder water.
4. The method of stripping nickel-phosphorous alloy plating from a steel workpiece without attacking the base metal, including the step of: immersing the workpiece in a stripping bath maintained at a temperature no greater than about 150 Fahrenheit and containing about 41.5 mole percent fuming nitric acid, about 24.5 mole percent hydrofluoric acid, and the remainder water.
References Cited in the file of this patent UNITED STATES PATENTS 1,974,570 Kiefer Sept. 25, 1934 2,200,486 Burdick May 14, 1940 2,371,529 Loose Mar. 13, 1945 2,541,083 McDermotte Feb. 13, 1951 2,564,749 Bried Aug. 21, 1951 2,569,158 Francis Sept. 25, 1951 2,740,700 Fuller Apr. 3, 1956 FOREIGN PATENTS 503,304 Canada May 25, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2 954 289 September 27 196 Bert J. Sherwood e1; alt,
It is hereby certified that error appears in the-printed specificatio of the above numbered patent requiring correction and that the said Letter Patent should read as corrected below.
Column 2 line 71 for "quantity" read quality a Signed and sealed this 11th day of April 1961 (SEAL) Att t: sR l lEsT w. SWIDER ARTHUR W. CROCKER Attesting Oflicer Actmg Commissioner of Patents
Claims (1)
1. THE METHOD OF STRIPPING NICKEL-PHOSPHOROUS ALLOY PLATING FROM A STEEL WORKPIECE WITHOUT ATTACKING THE BASE METAL, INCLUDING THE STEP OF: IMMERSING THE WORKPIECE IN A STRIPPING BATH CONTAINING FROM ABOUT 41.5 MOLE PERCENT TO ABOUT 68.4 MOLE PERCENT FUMING NITRIC ACID, FROM ABOUT 2.9 MOLE PERCENT TO ABOUT 24.5 MOLE PERCENT HYDROFLUORIC ACID, AND THE REMAINDER WATER.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US639630A US2954289A (en) | 1957-02-12 | 1957-02-12 | Dissolving of nickel-phosphorous alloys |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US639630A US2954289A (en) | 1957-02-12 | 1957-02-12 | Dissolving of nickel-phosphorous alloys |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2954289A true US2954289A (en) | 1960-09-27 |
Family
ID=24564911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US639630A Expired - Lifetime US2954289A (en) | 1957-02-12 | 1957-02-12 | Dissolving of nickel-phosphorous alloys |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2954289A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3104167A (en) * | 1960-02-11 | 1963-09-17 | Philco Corp | Method and solution for selectively stripping electroless nickel from a substrate |
| US3222289A (en) * | 1962-10-05 | 1965-12-07 | Walter E Clark | Dissolution of zirconium in titanium equipment |
| US3878006A (en) * | 1973-10-26 | 1975-04-15 | Mica Corp | Selective etchant for nickel/phosphorus alloy |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1974570A (en) * | 1930-01-28 | 1934-09-25 | Allegheny Steel Co | Pickling solution |
| US2200486A (en) * | 1939-05-10 | 1940-05-14 | Western Electric Co | Material and method for removing coatings of nickel or the like from a metal base |
| US2371529A (en) * | 1941-09-20 | 1945-03-13 | Dow Chemical Co | Removal of electrodeposited metals |
| US2541083A (en) * | 1945-08-25 | 1951-02-13 | Sperry Corp | Electroplating on aluminum |
| US2564749A (en) * | 1949-08-16 | 1951-08-21 | Hercules Powder Co Ltd | Stainless steel pickling bath solution |
| US2569158A (en) * | 1946-02-21 | 1951-09-25 | United States Steel Corp | Method of removing scale from ferrous articles |
| CA503304A (en) * | 1954-05-25 | Westinghouse Electric Corporation | Etching solution and process | |
| US2740700A (en) * | 1954-05-14 | 1956-04-03 | Bell Telephone Labor Inc | Method for portraying p-n junctions in silicon |
-
1957
- 1957-02-12 US US639630A patent/US2954289A/en not_active Expired - Lifetime
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA503304A (en) * | 1954-05-25 | Westinghouse Electric Corporation | Etching solution and process | |
| US1974570A (en) * | 1930-01-28 | 1934-09-25 | Allegheny Steel Co | Pickling solution |
| US2200486A (en) * | 1939-05-10 | 1940-05-14 | Western Electric Co | Material and method for removing coatings of nickel or the like from a metal base |
| US2371529A (en) * | 1941-09-20 | 1945-03-13 | Dow Chemical Co | Removal of electrodeposited metals |
| US2541083A (en) * | 1945-08-25 | 1951-02-13 | Sperry Corp | Electroplating on aluminum |
| US2569158A (en) * | 1946-02-21 | 1951-09-25 | United States Steel Corp | Method of removing scale from ferrous articles |
| US2564749A (en) * | 1949-08-16 | 1951-08-21 | Hercules Powder Co Ltd | Stainless steel pickling bath solution |
| US2740700A (en) * | 1954-05-14 | 1956-04-03 | Bell Telephone Labor Inc | Method for portraying p-n junctions in silicon |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3104167A (en) * | 1960-02-11 | 1963-09-17 | Philco Corp | Method and solution for selectively stripping electroless nickel from a substrate |
| US3222289A (en) * | 1962-10-05 | 1965-12-07 | Walter E Clark | Dissolution of zirconium in titanium equipment |
| US3878006A (en) * | 1973-10-26 | 1975-04-15 | Mica Corp | Selective etchant for nickel/phosphorus alloy |
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