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

• 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 4 .Z Be r1 it r i g a gi d a chloride ion in the an idu nt of 0.0] to 0.5 moles/liter, a copper ion in the amount of about 0.01 to 0.l moles/- liter, and a source of tellurium or selenium ions in the amount of approximately 0.005 to 0.2 moles/liter.
• the molar ratio of tellurium or selenium ions to chloride ions is in the general range of about one to three.
• 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 l5 grams of Te 0 or Se 0 with about 10 to 12 ml. of NaOH or KOH, diluting the solution obtained to about 150 ml., and thereafter filtering out the precipitate. A preferred concentration for the hydroxide 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 solution is to directly admix predetermined amounts of Te 0 or 5e0 HNO CuSO, 5H O, and NaCl.
• This procedure T is somewhat less expensive than going through the first approach, however, at times it may be found that combining the TeO or SeO directly with HNO produces a somewhat violent reaction.
• the first mentioned procedure is accordingly preferred at the present time.
• EXAMPLE I A solution was made up of 500 mil. HNO 5.7 g. Cu- SO .5H O, 3.3 g. NaCl and 3.0 g. FeCl which were diluted to l liter. A stainless steel part having a nickel deposit thereon of about 1 mil in thickness was immersed therein. and it took about 87 seconds before the deposit was removed.
• EXAMPLE II There was formulated a solution containing 500 ml. HNO 5.7 g. CuSO .5H O, 3.3 g. NaCl, 2.0 g. ofa commercially available strip aid (composition unknown), and this mixture diluted to 1 liter. It took about 141 seconds to remove a 1 mil thick nickel deposit from a stainless steel part.
• EXAMPLE III A solution was made up of 500 ml. HNO 5.7 g. Cu- SO .5H O, 3.3 g. NaCl and 1.5 g. Na TeO which were diluted to 1 liter. It only took 38 seconds to strip a l mil nickel deposit from a stainless steel part.
• Example III The procedure of Example III was again followed, except that 1.5 g. NaF was used in place of the Na TeO A nickel deposit of the same thickness took l 10 sec onds to be removed from a stainless steel part.
• EXAMPLE VI There was formulated a stripping solution containing 500 ml. HNO 5.7 g. CuSO .5H O, 3.3 g. NaCl, 1 g. KBrO and 0.3 g. KIO which was diluted to l liter. A l mil nickel deposit was removed from a stainless steel part in seconds.
• EXAMPLE Vll A solution was made up of 500 ml. HNO 5.7 g Cu- SO .5H O, 3.3 g. NaCl and 1 ml. bromine, the mixture being diluted to 1 liter. A 1 mil nickel deposit was stripped from a stainless steel part in 94 seconds.
• EXAMPLE Vlll There was formulated a stripping solution containing 500 ml. HNO 5.7 g. CuSO .5H O, 3.3 g. NaCl. and ml. Na TeO solution prepared as earlier described, and this mixture was diluted to 1 liter. A nickel deposit of a thickness of 1 mil was stripped in only 58 seconds.
• EXAMPLE lX A solution was prepared as in Example Vlll, but the amount of NaJeO solution was increased to ml. A deposit of the same thickness was removed in only 33 seconds.
• EXAMPLE X There was formulated a stripping solution containing 2 g/l TeO 600 g/l HNO 5.7 g/l CuSO .5H O and 3.3 g/l NaCl. An unwanted nickel deposit one mil thick was stripped from a stainless steel part in 27 seconds. which is about 30% faster than commerically available strippers.
• potassium hydroxide can readily be substituted for sodium hydroxide; potassium, manganese or cupric chloride can be used in place of sodium chloride; and cupric nitrate or chloride are 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, thereby satisfying the hydrogen ion requirement by a less expensive acid.
• 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.
• 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.
• composition as defined in claim 1 in which the copper ion is present in concentrations of about 0.0l to 0.5 M.
• composition as defined in claim I in which the nitric acid is approximately 42 Be. and is present in an amount of about 4.5 to 14.5 M.
• An aqueous solution for stripping accumulated nickel deposits from plating apparatus which contains therein about 2 to l0 grams per liter of tellurium or selenium dioxide, 600 to 850 grams per liter of nitric acid, 2 to 20 grams per liter of copper sulfate, and 3.5 to 35.5 grams per liter of a source of chloride ions.

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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)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Chemically Coating (AREA)

Priority Applications (12)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Cited By (11)

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Citations (6)

• 1973
  • 1973-06-18 US US00370889A patent/US3856694A/en not_active Expired - Lifetime
  • 1973-06-18 ES ES427394A patent/ES427394A1/es not_active Expired
• 1974
  • 1974-05-16 ZA ZA00743138A patent/ZA743138B/xx 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/de not_active Expired
  • 1974-06-14 IT IT51539/74A patent/IT1013479B/it active
  • 1974-06-15 JP JP6864374A patent/JPS5647263B2/ja not_active Expired
  • 1974-06-17 BR BR4948/74A patent/BR7404948D0/pt unknown
  • 1974-06-17 GB GB2674074A patent/GB1475327A/en not_active Expired
  • 1974-06-18 FR FR7421109A patent/FR2233418A1/fr not_active Withdrawn

Patent Citations (6)

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