Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
  • C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
• • 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

• the invention relates to a composition comprising at least 40 to 90% by weight of Co, 10 to 50% by weight of Ni and 3 to 20% by weight of P, as an anti-wear layer with low coefficient of friction galvanically deposited. on a substrate, as well as an article of manufacture comprising an anti-wear surface layer with low coefficient of friction deposited by galvanic means, this layer having the composition defined above, and this layer itself.
• Such layers of Co-Ni-P alloy generally have the friction properties, in particular the coefficient of friction and the wear resistance, which can be expected by extrapolating the data known for the layers of alloy of Ni-P, Co-P, Co-Ni and their mixtures.
• FIG. 1 represents the lifetime of a friction layer as a function of the composition of the Co-Ni-P alloy
• FIG. 2 represents the wear rate of a friction layer as a function of the composition of the Co-Ni-P alloy.
• Galvanic deposits were obtained from aqueous electrolytes containing dissolved salts of nickel, cobalt as well as salts of phosphites or phosphorous acid. These electrolytes were subjected to the passage of a current between an anode and a cathode. This cathode was the place of deposition of layers consisting of a Co-Ni-P alloy.
• the parameters of the electroplating ie the concentration of the salts contained in the electrolyte, the cathodic current density, the pH and the temperature of the electrolyte, it was possible to obtain alloy layers of which the cobalt content was between 0 and 93%, the Ni content between 0 and 98% and the phosphorus content between 3 and 20%.
• FIGS. 1 and 2 are presented the results of measurements carried out on brass discs covered with a layer of Co-Ni-P alloy with a thickness of 10 ⁇ m and comprising 10% by weight of phosphorus.
• the conditions of measurements were as follows: 5mm diameter ball in stainless steel, load 5N, relative humidity 40%, temperature 25 ° C, radius of the friction track 8mm, friction speed 10cm / s, no lubrication.
• Figure 1 shows, depending on the composition of the alloy, the life of a friction layer expressed in number of turns (n) which produces an increase in the coefficient of friction ( ⁇ ) up to the value 0.3 .
• Figure 2 shows, depending on the composition of the alloy, the wear rate expressed in 10 -15 m3 / mN.
• alloy compositions leading to increased lifetimes correspond to those which give the lowest rate of wear on the ball-plane tribometer, this rate of wear being expressed in standard lost volume in relation to the load and the path traveled by the ball on the plane.
• the type of friction obtained in the absence of lubrication using the layer studied is particularly advantageous because of the simultaneous obtaining of a low coefficient of friction and good resistance to wear.
• Co-Ni-P alloy layers in the compositions according to the invention that is to say promoting friction resistance, was tested as to its functioning as an electrical contact for connectors. It turned out that at a charge of 1N against a gold partner and after 10 days of exposure to 95% relative humidity at 25 ° C the contact resistance had average values of 20 milliohms and isolated values exceeding 100 milliohjis. On the other hand, when these layers were covered with 0.1 ⁇ m of gold, the contact resistance measured after 100 days of test under the conditions cited did not exceed 10 milliohms. In conclusion, the Co-Ni-P alloy layers in the compositions according to the invention, covered with a gold flash, can serve as an electrical contact of excellent quality.
• a series of solid lubricants with a particle size of 0.2 to 20 ⁇ m could be incorporated as finely dispersed particles and regularly distributed in the CoNi-P alloy at levels between 1 and 10% by weight, namely carbon fluoride ["Foracarb", a product of the firm PUK], MoS2, graphite, silver powder, PTFZ, 3aF2, CaF2, an eutectic mixture of 3aF2.CaF2, hexagonal BN and encapsulated oil.
• Binary and ternary mixtures of dispersoids have also been codeposited, in particular PTFE with MoS2, carbon fluoride with MoS2, carbon fluoride with encapsulated oil, carbon fluoride with MoS2 and encapsulated oil as well as silver powder with BaF2.
• a Co-Ni-P alloy matrix with a composition of 65% -25% -10% by weight containing carbon fluoride as a dispersoid has shown a lifetime 50 times greater than a Co alloy matrix -Ni-P of a composition of 28% -60% -12% by weight containing the same amount of carbon fluoride. This clearly shows that the particular composition of the Co-Ni-P alloy according to the invention is not only favorable to friction as a pure alloy but also as a matrix for composite deposits.
• Composite deposits have been obtained with anti-abrasive dispersoids, in particular oxides, carbides, nitrides and diamond powder.
• An anti-wear effect was observed when the Co-Ni-P alloy of a composition according to the invention was used as matrix, and this anti-wear effect was found to be significantly more effective than with metallic matrices of Ni or Co or of alloy of Ni-P or of Co-P or of Co-Ni or of Co-Ni-P of a composition of
• a layer of Co-Ni-P alloy was deposited electrolytically in a thickness of 10 ⁇ m on a brass disc 5 cm in diameter and 5 mm thick under the following conditions: composition of the electrolyte: (g / 1)
• the brass disc was coated with a layer of 10 ⁇ m thick Co-Ni-P alloy with a composition of 60% -30% - 10% by weight.
• This disc was subjected to tribological tests on a ball-disc machine as described above in relation to Figures 1 and 2.
• the coefficient of friction at the start was 0.15 and it took 1100 laps to change it to 0.3.
• the friction groove was analyzed with a roughness tester and the used volume was evaluated geometrically at approximately 10 x 10 m3 / mN.
• Example 1 The test described in Example 1 was repeated under the same experimental conditions but at 2A / dm2 and for 60 minutes.
• the layer obtained had a thickness of approximately 10 ⁇ m and its composition was 28% by weight of Co, 60% by weight of Ni and 12% by weight of P.
• the lifetime measured under the same conditions until a friction coefficient of 0.3 was obtained was 40 revolutions, and the wear rate was approximately 500 x 10, -15m3 / mN
• a layer of Co-Ni-P alloy was deposited by autocatalyticgalvanic coating in a thickness of 10 ⁇ m on a brass disc 5 cm in diameter and 5 mm thick under the following conditions: 'composition of the electrolyte: (M )
• a thickness of approximately 10 ⁇ m was obtained after 95 minutes.
• the composition of the alloy was 50% by weight of Co, 45% by weight of Ni and 5% by weight of P.
• the billeplan tests showed a lifetime until obtaining a coefficient of friction 0.3 to 600 turns and a wear rate of approximately 50 x 10 -15 m3 / mN.
• Composite deposits of Co-Ni-P alloy containing 10% by volume of carbon fluoride with an average particle size of 3 ⁇ m and regularly dispersed in the metal matrix were deposited from the electrolyte described in the example pie 1 but also containing 25g / l of carbon fluoride particles and 0.6g / l of quaternary ammonium salt
• the ball-plane friction tests showed a lifetime until a coefficient of friction of 0.3 of 30,000 revolutions was obtained for the first test described and 1600 revolutions for the second test described.
• the wear rate was 0.2 x 10 -15 m3 / mN for the first test described and 14 x 10 -15 m3 / mN for the second test described.
• the deposited layer was approximately 10 ⁇ m thick and the matrix metal contained 60% by weight of Co, 30% by weight of Ni and 10% by weight of P.
• Ball-plane friction tests under vacuum have shown a lifetime up to obtaining a coefficient of friction of 0.3 of 18,000. turns for the first test described and 650 turns for the second test described.
• the wear rate was 3.5 x 10 -15 m3 / mN for the first test described and 85 x 10 -15 m3 / mN for the second test described.
• Composite deposits of Co-Ni-P alloy containing 15% by volume of CaF2 particles with an average particle size of 0.8 ⁇ m were obtained from the electrolyte described in example 1 but also containing 30 g / l of CaF2 particles and lg / l of the compound
• rotary stainless steel seals were treated cathodically at 12 A / dm2 for 9 minutes and the layer obtained was 10 ⁇ m thick.
• the composition of the metal matrix was 60% by weight of Co, 30% by weight of Ni and 10% by weight of P.
• the life of the sealed rotary seals was measured at 450 ° C in operating hours up to a given value of the moment of rotation.
• the joints treated to obtain a layer of Co-Ni-P / CaF2 showed a lifetime of 265 hours, the joints treated to obtain a layer of Co / CaF2 showed a lifetime of 148 hours, and the joints not treated have shown a lifespan of 96 hours.
• Composite deposits of Co-Ni-P alloy containing Cr 2 O 3 particles with an average particle size of 0.5 ⁇ m were obtained from the electrolyte described in Example 1 but also containing 30 g / l of Cr 2 O 3 particles.
• the deposited layer was approximately 10 ⁇ m thick and the matrix
• metal had the following composition: 50% by weight of Co, 30% by weight of Ni and 10% by weight of P. This matrix contained about 15% by volume of Cr 2 O 3 .
• the ball-plane friction tests showed a lifetime until a friction coefficient of 0.3 of 600 revolutions was obtained for the first test described and 25 turns for the second test described.
• the wear rate was 0.08 x 10 -15 m3 / mN for the first test described and 3.5 x 10 -15 m3 / mN for the second test described.

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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)
• Lubricants (AREA)
• Electroplating Methods And Accessories (AREA)

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Cited By (6)

Citations (2)

• 1988
  • 1988-08-25 CH CH315888A patent/CH677934A5/fr not_active IP Right Cessation
• 1989
  • 1989-06-21 WO PCT/CH1989/000117 patent/WO1990002220A1/fr unknown

Patent Citations (2)

Non-Patent Citations (2)

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