WO1988004701A1 - Surface de contact recouverte de nickel a orientation cristallographique preferentielle - Google Patents

Surface de contact recouverte de nickel a orientation cristallographique preferentielle Download PDF

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Publication number
WO1988004701A1
WO1988004701A1 PCT/US1987/003079 US8703079W WO8804701A1 WO 1988004701 A1 WO1988004701 A1 WO 1988004701A1 US 8703079 W US8703079 W US 8703079W WO 8804701 A1 WO8804701 A1 WO 8804701A1
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WO
WIPO (PCT)
Prior art keywords
contact
terminal
contact surface
surface portions
nickel
Prior art date
Application number
PCT/US1987/003079
Other languages
English (en)
Inventor
Thomas Francis Davis
David Kahn
Original Assignee
Amp Incorporated
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Amp Incorporated filed Critical Amp Incorporated
Publication of WO1988004701A1 publication Critical patent/WO1988004701A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating 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
    • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/70—Coupling devices
    • H01R12/71—Coupling devices for rigid printing circuits or like structures
    • H01R12/712—Coupling devices for rigid printing circuits or like structures co-operating with the surface of the printed circuit or with a coupling device exclusively provided on the surface of the printed circuit
    • H01R12/716—Coupling device provided on the PCB

Definitions

  • Electrical terminals or other devices having contact surfaces are frequently electroplated with a metal which has superior contact properties as compared to the basis metal, for example, it is common to plate copper terminals with nickel and with a thin gold plating over the nickel to function as the contact surfaces. Tin is also frequently used as a plating for terminals or other contact devices.
  • the ideal, and nearly perfect, contact surface is electroplated gold but other metals, particularly tin, are frequently used because of the very high cost of gold.
  • Electroplated nickel has been used on terminals and other contact devices to a limited extent as a contact surface
  • Nickel has been used in the past on contact surfaces where the normal force (the contact force exerted on the contact surface) is 500 grams or greater but has not been considered suitable for contact surfaces when the normal force is much below 500 grams.
  • Many electrical terminals are designed to produce a normal force of about 100 grams and a higher normal force is not practical because of the small size of the terminals and the limitations of the metal from which the terminals are manufactured.
  • many of the commonly used types of connecting devices for integrated circuit chip carriers contain contact terminals which, because of size limitations, exert a normal force in the 100 to 200 gram range and it is generally regarded as necessary to use a gold contact surface on such terminals notwithstanding the added cost.
  • an electroplated nickel surface on a terminal device has a particular grain orientation, the development of the oxide film on the nickel surface will take place only to a limited extent, and as a result, a stable low resistance electrical connection will be obtained when the plated device is placed in service.
  • the electroplated surface has about 50 percent of the volume fraction of the crystallites therein preferentially oriented so that their ⁇ 100 ⁇ atomic planes are substantially parallel to the contact surface itself, the characteristics of the connection will be outstanding and for many purposes will be comparable to a gold plated contact.
  • the invention comprises an electrical contact terminal having contact surface portions which are engageable with complementary contact surface portions.
  • the terminal is characterized in that the contact surface portions are of electrodeposited nickel and comprise nickel crystallites. At least 50 percent of the volume fraction of the crystallites are preferentially oriented with their ⁇ 100 ⁇ atomic planes substantially parallel to the contact surface portions as determined by X-ray diffraction orientation analysis.
  • the terminal may be of the type which is intended to be disengageably coupled to a complementary contact terminal with the contact surface portions being slidable against complementary contact surface portions of the complementary contact terminal.
  • the terminal and the complementary contact terminal may, for example, be a contact pin and a contact socket. Both of the terminals may have electroplated nickel on their contact surfaces preferentially oriented as explained above.
  • the terminal may be of the type intended for engagement with a wire.
  • the terminal may have a wire receiving slot therein which has a width which is less than the diameter of the wire.
  • the edge surfaces of the slot, which engage the wire constitute the contact surface portions which are electroplated with preferentially oriented nickel.
  • the contact terminal may have a ferrule portion which is intended for crimping onto a wire. The ferrule portion has ferrule surface portions which are against the wire after crimping and the contact surface portions which are electroplated with nickel- are the ferrule surface portions.
  • Figure 1 shows a face centered cubic lattice
  • FIGS. 2 through 4 are curves which explain the improved results achieved in the practice of the invention.
  • Figure 5 is a cross-sectional view of a circuit board connector of a type with which the present invention can be used;
  • Figure 6 is a perspective view showing a terminal pin and a terminal socket;
  • Figure 7 is a perspective view of a terminal having a wire receiving slot.
  • Electrodeposited platings like virtually all metals used commercially, are composed of a multitude of individual grains or crystallites. Each crystallite constitutes a domain in which all of the atoms of the metal are arranged in precisely predetermined positions relative to each other in a specific crystallographic habit or form.
  • Figure 1 shows an individual lattice having atoms in the face centered cubic habit which is the crystallographic habit of electrodeposited nickel.
  • An individual crystallite is composed of a multitude of cubic lattices of the type shown in Figure 1, with all of the lattices in the same crystallite being in the same orientation and with the individual atoms shown in Figure 1 being shared with additional lattices. Adjacent crystallites will usually not be in the same orientation but will be displaced in one way or another from their neighbors so that the lattices in two additional crystallites will be in different orientations.
  • the orientation of a crystallite is determined with reference to the positions of the atoms relative to the XYZ axes shown in Figure 1.
  • the face centered cubic lattice shown in Figure 1 has eight corner atoms indicated by the reference numerals 2, 4, 6, 8, 10, 12, 14, and 16, which define the cube. It also has an atom on each of its eight faces which are indicated by the reference numerals 3, 5, 7, 9, 11, and 13.
  • the corner atoms 2, 4, ***14, 16 are shared by seven adjacent lattices in the crystallite and each of the facial atoms 3, 5 , ***11, 13 is shared with one adjacent lattice.
  • Crystallographers refer to the various crystallographic planes of a lattice of the type shown in Figure 1, which planes are defined by different groups of atoms in the lattice.
  • the planes are identified by the locations of their intersections with the XYZ axes.
  • the plane which contains the atoms 2, 4, 6, 8 and 3 is referred to as the (001) plane for the reason that it intersects the Z axis and is parallel to the X axis and the Y axis.
  • the plane containing the atoms 6, 8, 12, 14, and 7 is referred to as the (010) plane
  • the plane containing the atoms 2, 8, 14, 16, and 11 is referred to as the (100) plane.
  • the planes on the surfaces of the lattice are composed of four atoms which are equidistant from each other, to form a square, and a centrally located atom, for example, the (001) plane is composed of the atoms 2, 4, 6, 8 and the central atom 3. Since all of these planes which form the faces of the lattice are identical to each other with respect to the locations of the atoms therein, they are collectively referred to as the ⁇ 100 ⁇ planes, with the distinctive brackets indicated rather than parentheses which are used to identify specific planes.
  • crystallographic planes in the lattice shown in Figure 1 would have different indices.
  • the (111) plane would contain (i.e., intersect) the atoms 4, 13, 16, 9, 12 and 6, since this plane intersects each of the three axes at a unit distance from the origin which is occupied by the atom 10.
  • about 50 volume percent of the individual crystallites in the plating have their ⁇ 100 ⁇ planes parallel to the contact surface and the remaining 50 percent of the crystallites may be more or less randomly oriented with any other planes parallel to the contact surface.
  • Figures 5 through 7 show typical terminals on which platings in accordance with the invention can be used.
  • Figure 5 shows a connector 18 for a circuit board 26.
  • the connector 18 comprises a housing 20 having a trough-like opening 24 which receives the lower edge of the circuit board.
  • the housing contains terminals 28 which are arranged in two rows as shown so that the contact portions 30 of the terminals will contact the contact pads 34 on the side surfaces 32 of the circuit board. These contact pads and the contact portions 30 of the terminals can be plated with oriented nickel in accordance with the invention.
  • Figure 6 shows a contact pin 36 and a socket 38, the pin and socket being crimped onto wires 40.
  • the surface of the pin and the internal surface of the socket can be plated with oriented nickel for improved contact characteristics.
  • Figure 7 shows a terminal 42 of the type which has wire receiving slots 48 which are in two side-by-side plate-like members 44 that are connected by strap members 46.
  • the edges of the slots 48 are the contact surfaces and can also be provided with nickel platings in accordance with the invention.
  • Electroplated contact surfaces in accordance with the invention can be produced from a plating system having a bath of the following composition:
  • a typical bath of this type has the following composition:
  • Sulfate baths of this type will, under many operating conditions, produce a plating having a preferred ⁇ 111 ⁇ orientation plating.
  • a preferred ⁇ 100 ⁇ plating in accordance with the invention can be obtained with a sulfate bath if the plating conditions regarding pH, bath temperature, and current density are within certain limits.
  • a preferred ⁇ 100 ⁇ orientation plating has been obtained using a sulfate bath when the pH was 3.5, the current density was 10 amps/square foot, and the bath temperature was 60 degrees Celsius.
  • plating baths which are capable of producing platings having the preferred ⁇ 100 ⁇ orientation of the present invention.
  • parameters of the plating process precision bath composition, temperature, pH, and current density
  • Electrodeposited nickel platings in accordance with the invention can be inspected by means of well-known X-ray diffraction techniques.
  • a plating line for the practice of the invention can be established by using- one of the preferred baths discussed above and setting the plating conditions within the plating parameters which will produce the desired ⁇ 100 ⁇ orientation in the crystallites.
  • the plated product can be inspected at the time of initial start-up for the desired orientation. After it has been determined that the desired orientation is being achieved, it is thereafter only necessary to carefully maintain the plating conditions.
  • a suitable apparatus for obtaining diffraction patterns is a Siemens Kristalloflex 4 X-Ray generator and a Type F diffractometer with a diffracted beam monochromotor.
  • the orientation of the nickel platings is observed by measuring the areas of the individual peaks in the powder diffraction pattern. Since the diffractometer uses the Bragg Brentano geometry, diffraction occurs from crystallites whose atomic planes are essentially parallel to the plating surface. The relative peak areas (which are proportional to the volume fraction of crystallites corresponding to this orientation) for a random distribution of nickel crystallites have been published by the JCPDS-International Centre for Diffraction Data.
  • the relative area under the 200 peak (the 100 peak has zero intensity for a face centered cubic symmetry) will be correspondingly larger than it would be for a random orientation.
  • a simple orientation parameter may be constructed by dividing the area of the peak in question by the total area of all the observed peaks in the pattern, and normalizing this number by dividing by a similar ratio obtained from the random orientations listed in the JCPDS file.
  • the oxide which normally forms on an electrodeposited nickel surface has a thickness of about 20AU (Angstrom units) .
  • the ⁇ 100 ⁇ planes of nickel crystallites appear to resist the formation of an oxide; the oxide formed on the surfaces of the ⁇ 100 ⁇ planes reaches a thickness of only about 3AU and stabilizes at that thickness. It seems probable that the extremely thin oxide which forms on the ⁇ 100 ⁇ planes does not present an effective barrier to the passage of an electrical current and for practical purposes the surface can be considered free of oxide or nearly so.
  • Figure 2 shows the resistance versus load contact force characteristics for three of the crystallographic planes of nickel single crystals.
  • the data for these curves were obtained by preparing single crystals of nickel in a manner such that the ⁇ 100 ⁇ plane was exposed on one specimen, the ⁇ 111 ⁇ plane was exposed on another specimen, and the ⁇ 110 ⁇ plane was exposed on the third specimen.
  • the contact resistance of each specimen was determined by contacting the surface with a gold test probe under varying and increasing load conditions ranging from 10 grams to 500 grams.
  • the test current was 49 illiamperes and the voltage was 50 millivolts.
  • the data obtained were then plotted on logarithmic scales, the resistance being indicated by the vertical axis and the test probe load by the horizontal axis.
  • Samples of nickel plated terminals have been tested to compare and evaluate two nickel plating variations.
  • One set of samples was prepared using a nickel sulfamate bath. The plating parameters were adjusted to produce a predominantly ⁇ 100 ⁇ oriented nickel plating as discussed above.
  • a second set of connector samples was prepared using a sulfate nickel bath. The parameters of this bath were adjusted to produce a predominantly ⁇ 111 ⁇ oriented nickel plating.
  • Figure 3 shows the effect of a 103 day heat age test on the three plating types.
  • the prepared connectors were heat soaked in an oven for 103 days at a temperature of 105 degrees Celsius with resistance monitoring at room temperature.
  • the plot of resistance change versus cumulative percentage shows that all 99 samples of the terminals plated with predominantly ⁇ 100 ⁇ oriented nickel showed a resistance change after the test that was less than 3.21 milliohms.
  • the ⁇ 111 ⁇ plated terminals on the other hand, had numerous terminals that showed a resistance change greater than the failure criterion of 6.50 milliohms.
  • Figure 4 shows the results of a test of the two types of plating after 20 days of exposure to an Industrial Mixed Flowing Gas environment (AMP Test Specification 109-85, Rev. 0) .
  • This environment includes pollutant gas concentrations of 100 + 20 ppb H 2 S; 200 + 50 ppb N0 2 ; and 20 + 5 ppb Cl_.
  • the temperature was maintained at 30 degrees Celsius and the relative humidity (RH) was 75 percent.
  • nickel platings in accordance with the invention can be used under a wide variety of circumstances where a gold contact surface would otherwise be required.
  • the specific terminals described and shown in the drawings are shown by way of example, and platings in accordance with the invention can be used on many other types of terminals and other electrical devices which have contact surfaces such as cylindrical terminals which are intended to be crimped onto wires.
  • the barrel of the terminal and the end of the wire can be provided with oriented nickel to improve the quality of the contact surfaces.

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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)
  • Electroplating Methods And Accessories (AREA)

Abstract

Dispositif de contact électrique, tel qu'une borne de connexion (28, 36, 38, 42) ou une surface de contact, sur lequel du nickel a été déposé par électrolyse. Les cristallites du nickel sont de préférence orientées de sorte qu'au moins 50 % de la fraction de volume des cristallites ont leurs (100) plans atomiques sensiblement parallèles à la surface de contact. A de nombreux égards, la surface de nickel à orientation préférentielle est comparable à une surface de contact recouverte d'or.
PCT/US1987/003079 1986-12-22 1987-11-27 Surface de contact recouverte de nickel a orientation cristallographique preferentielle WO1988004701A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US94543386A 1986-12-22 1986-12-22
US945,433 1986-12-22

Publications (1)

Publication Number Publication Date
WO1988004701A1 true WO1988004701A1 (fr) 1988-06-30

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PCT/US1987/003079 WO1988004701A1 (fr) 1986-12-22 1987-11-27 Surface de contact recouverte de nickel a orientation cristallographique preferentielle

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2695259A1 (fr) * 1992-09-03 1994-03-04 Souriau & Cie Borne de contact électrique en nickel pour connecteur, connecteur et procédé de fabrication.
CN108779569A (zh) * 2016-03-09 2018-11-09 Ｊｘ金属株式会社 镀Ni的铜或铜合金材料、使用该材料的连接器端子、连接器以及电子部件

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4564565A (en) * 1984-05-18 1986-01-14 Burlington Industries, Inc. Method of making low contact resistance metallic coatings and electrical contacts so produced
US4610932A (en) * 1984-12-06 1986-09-09 At&T Technologies, Inc. Electrical contacts
WO1986007205A1 (fr) * 1985-05-20 1986-12-04 American Telephone & Telegraph Company Dispositif de contact electrique a base de nickel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4564565A (en) * 1984-05-18 1986-01-14 Burlington Industries, Inc. Method of making low contact resistance metallic coatings and electrical contacts so produced
US4610932A (en) * 1984-12-06 1986-09-09 At&T Technologies, Inc. Electrical contacts
WO1986007205A1 (fr) * 1985-05-20 1986-12-04 American Telephone & Telegraph Company Dispositif de contact electrique a base de nickel

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Chemical Abstracts, vol. 77, no. 12, 18 September 1972, (Columbus, Ohio, US) St. Vitkova et al.: 'Effect of the adsorption of halide ions on the change in the texture of electrodeposited nickel', see page 568, abstract 82821v & Izv. Otd. Khim. Nauki, Bulg. Akad. Nauk. 1971, vol 4, no. 4, pages 671 - 679 *
J. Electrochem. Soc.: Electrochemical Science and Technology, vol. 125, no. 12, December 1978, D. Tench et al.: 'the effect of depassivation at specific crystal facets on the state of activation of nickel substrates for electrodeposition, pages 1940 - 1945 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2695259A1 (fr) * 1992-09-03 1994-03-04 Souriau & Cie Borne de contact électrique en nickel pour connecteur, connecteur et procédé de fabrication.
EP0586300A1 (fr) * 1992-09-03 1994-03-09 F.C.I. - Framatome Connectors International Borne de contact électrique en nickel pour connecteur, connecteur et procédé de fabrication
CN108779569A (zh) * 2016-03-09 2018-11-09 Ｊｘ金属株式会社 镀Ni的铜或铜合金材料、使用该材料的连接器端子、连接器以及电子部件
EP3428324A4 (fr) * 2016-03-09 2019-08-21 JX Nippon Mining & Metals Corporation MATÉRIAU EN CUIVRE OU ALLIAGE DE CUIVRE PLAQUÉ DE Ni, ET BORNE DE CONNECTEUR, ET CONNECTEUR ET COMPOSANT ÉLECTRONIQUE DANS LESQUELS LEDIT MATÉRIAU EN CUIVRE OU LEDIT ALLIAGE DE CUIVRE EST UTILISÉ

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