Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/56—Electroplating: Baths therefor from solutions of alloys
  • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt

Definitions

• Electroforming which is sometimes referred to as electrotabricating, is a process which has been used to cre ate articles of a variety of sizes and shapes. Examples of such articles are hypodermic needles, microscopic grooves of high fidelity record stampers, huge dish like molds for forming plastic canopies, fountain pen caps and electrotype. When accurately controlled, the electroforming process allows for the formation of intricate parts with accurate dimensions and at relatively low cost.
• one of the problems which must be solved before such a process can be adapted to the manufacture of articles to operate under highly stressed conditions such as in jet engines is that the metal or metal alloy which is electrodeposited to form the desired article must have sufficient strength and ductility to withstand the diflicult conditions to which an article would be subjected in operation.
• the present invention in one form, has recognized that a particular aqueous electroplating bath can be used to develop a nickel base, nickel-manganese alloy of unusual strength characteristics.
• Patent 1,026,628-Leuchter in 1912.
• Patent 2,377,321-Brown et al. and 11.8.
• Patent 2,905,- 601 mention the formation of a nickel-manganese alloy in the electrodeposition art.
• Another object is to provide an electrolyte and a method for electrodepositing a nickel-manganese alloy into an article shape which has strength characteristics unusual for an electroformed article.
• the present invention provides an electroformed Mi-Mn alloy including less than 1 Weight percent manganese and preferably consisting essentially of 0.030.8 weight percent manganese with the balance nickel.
• Strong articles of the alloy of this invention can be electroformed from an aqueous sulfamate nickel electroplating bath in which the manganese metal content is about 25 ounces per gallon and the nickel metal content is about 10l2 ounces per gallon, with the bath being operated at a temperature above about 120 F. preferably at a current density or" between about 20-75 amps per square foot.
• Aqueous solution A Nickel metal oz./gal 1 10.010.5 Boric acid do 4.5-5.0 pH 4.0-4.2 Temperature F 140 Current density amps/sq. ft 50 1 As nickel sulfamate.
• Aqueous Solution C that the addition of manganese as an alloying element with nickel resulted in unusual properties.
• the electrolyte solution used was as follows:
• Aqueous solution C Oz./ gal. Nickel metal (as sulfamate) 1.0.5 Manganese metal (as sulfamate) 4.0 Boric acid 4.0
• Aqueous Solution C at a pH of 3.5 and a temperature of F. was used at a current density of about 60 amps/sq. ft. with depolarized nickel anodes to produce a nickel-manganese alloy sheet 8" X 10" x 0.030".
• This material of 0.4 weight percent Mn, balance Ni showed that the hardness and heat stability of nickel alone is changed markedly by the inclusionof manganese.
• TAB LE II.-ELE C T ROLYIE BATH Ni Mn Temp. Current Example (oz./gal,) (oz./gal.) pH F.) density (amps. lit!) TAB LE IIL-PLATED DEPOSIT Example Mn (Wt. Stress 1 Hardness, Physical percent) R a con ditlon 1. 2 D. 1. 2 D. 0. S O 0. 6 A. 0. 5 A. 0. 3 A.
• I-I l1igh.
• the hardness and heat stability of the nickelmanganese alloy is markedly changed.
• the manganese content decreases as the temperature of the electroplating bath increases while the manganese content increases with current density.
• the manganese content was generally unaffected by variations in pH between about 1 and 5, although the physical condition of the alloy deposited at a pH of 1 was unusually poor as compared with that produced at a pH of 2.
• Examples 1-6 represent variations in the manganese content of the bath; Examples 7, 8, 18 and 19 represent variations in the current density at two different temperatures; Examples 9-13 represent variations in bath temperature and Examples 14-17 represent the efiect of change in pH.
• the hardness data shows that an alloy hardness of above about 40 Rockwell C (R results in too high a stress level in the alloy and leads to cracks in the material. Furthermore, a manganese content below about 0.8 Weight percent of the alloy results in a sound, strong alloy whereas alloys containing manganese at or above about 1.2 weight percent are brittle and highly stressed.
• the manganese metal content in the electrolyte of this invention lies in the range of about 2-5 ounces per gallon and the nickel metal content lies in the range of about -12 ounces per gallon.
• Both of the metals are present in the aqueous bath as metal sulfamate along with an agent such as boric acid normally used in nickel electroplating solutions.
• the temperature should be maintained above F., generally within the range of 120-160 F. and preferably in the range of -150" F.
• the pH between 2-5 resulted in satisfactory alloy with extraordinary material being produced at a pH between about 2-4.
• the data shows that an electroformed Ni-Mn alloy deposited from a sulfamate solution and including less than 1 weight percent Mn and preferably consisting escentially of 0.03-0.8 weight percent manganese with the balance nickel has unusual characteristics which were unrecognized prior to the present invention.
• Nickel metal content (as sulfamate) oz/gal. 10.5-11.0 Manganese metal content (as sulfamate) oz./gal. pH Temperature F. Current density amps/sq. ft. Hardness R
• the alloy rectangles were stabilized by heating at 800 F. for 16 hours and then air cooling to insure that no changes in the material would take place as a result of exposure to the test temperatures and to remove any entrapped hydrogen which is known to exist in slight amounts in the as-plated condition.
• any brittleness which might exist in the as-plated condition within the range of the alloy of this invention is caused mainly by cathodic hydrogen content. be imparted to such alloy by a low temperature anneal to degas the material without loss in strength.
• a photomicrograph of a cross section of the electrodeposited NiMn alloy of this invention have shown that the alloy does not have the conventional crystal structure that would normally be attributed to this type of alloy.
• the appearance of the structure is similar to that of untempered martensite. It is believed that the fine as-plated grain size is primarily responsible for the high mechanical properties of this alloy.
• an aqueous electrolyte consisting essentially of:
• the manganese metal and the nickel metal being in the electrolyte in the form of sulfatnates;
• the electrolyte having a pH of about 2-5.
• an aqueous electrolyte consisting essentially of:
• the manganese metal and the nickel metal being in the electrolyte in the form of sulfamates;
• the electrolyte having a pH of about 3.5-4.
• an aqueous electrolyte consisting essentially of a manganese metal content of about 2-5 oz./ gal. and a nickel metal content of about 10-12 oZ./ga1., the manganese metal and the nickel metal being in the electrolyte in the form of sulfamates; and
• an aqueous electrolyte consisting essentially of a manganese metal content of 2-5 oz./ gal. and a nickel metal content of 10-12 oz./gal., the manganese metal and the nickel metal being in the electrolyte in the form of sulfamates;

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Mechanical Engineering (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

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Citations (10)

• 1962
  • 1962-06-08 US US209963A patent/US3244603A/en not_active Expired - Lifetime
• 1963
  • 1963-05-22 GB GB20413/63A patent/GB1040457A/en not_active Expired
  • 1963-06-07 DE DE19631496798 patent/DE1496798A1/de active Pending

Patent Citations (10)

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