US3400012A - Process of plating metal objects - Google Patents

Process of plating metal objects Download PDF

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Publication number
US3400012A
US3400012A US374151A US37415164A US3400012A US 3400012 A US3400012 A US 3400012A US 374151 A US374151 A US 374151A US 37415164 A US37415164 A US 37415164A US 3400012 A US3400012 A US 3400012A
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US
United States
Prior art keywords
metal
plating
plated
driving
salt
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
Application number
US374151A
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English (en)
Inventor
Golben Michael
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
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 Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Priority to US374151A priority Critical patent/US3400012A/en
Priority to DE19651521382 priority patent/DE1521382C/de
Priority to CH800765A priority patent/CH461914A/de
Priority to GB23090/65A priority patent/GB1118312A/en
Application granted granted Critical
Publication of US3400012A publication Critical patent/US3400012A/en
Publication of US3400012B1 publication Critical patent/US3400012B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C24/00—Coating starting from inorganic powder
    • C23C24/02—Coating starting from inorganic powder by application of pressure only
    • C23C24/04—Impact or kinetic deposition of particles
    • C23C24/045—Impact or kinetic deposition of particles by trembling using impacting inert media
    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/54—Contact plating, i.e. electroless electrochemical plating

Definitions

  • This invention relates to the metal plating of conductive substrates. More particularly, the invention relates to a new and useful means for metal plating which is more convenient and less expensive than electroplating, which provides thicker coatings than can be obtained by displacement plating, and which preserves the simplicity of mechanical plating.
  • a composition of a driving, or plating inducing, metal and an ionizable salt of a metal to be plated are introduced into a liquid medium in'which the salt is soluble, which liquid medium is in contact with an electrically conductive substrate. Then, upon contact, as by mechanical agitation or otherwise, of the substrate to be plated with the driving metal, the plating metal deposits from solution onto the substrate and provides a smooth, uniform coating layer of any desired thickness.
  • the substrate to be plated may be a massive metal article, or small parts such as washers, hose clamps, screw fasteners, etc., or it may be itself a metal powder, the flakes or granules of which are to be plated.
  • the driving metal must be less ice noble, i.e. more active electrochemically in the solution in which it is suspended or with which it is contacted, than either the plating metal (provided by the metal salt) or the metal substrate to be plated.
  • this invention provides for producing a superior protective or decorative metal plating which is a finished product per se, directly on a conductive substrate.
  • the invention is also particularly useful in the preplating of small ferrous metal parts with tin prior to electrically or mechanically plating them with zinc, cadmium, or other corrosion-resistant metal.
  • One specific product contemplated by this invention is a novel storable product which can be used to impart a uniform smooth metal plating to electrically conductive parts. I
  • copper is generally satisfactory as a pre-plating metal in mechanical plating operations, there are environments, e.g., certain gaseous environments, wherein copper platings (even copper undercoatings) are undesirable because of the polymer-inducing catalytic effect of the copper. Also, copper suffers from the disadvantage that its natural reddish color and its oxidized'black color contrast with that of the final plating. Thus, the copper sometimes shines through a subsequently applied plating, which then may appear mottled or off-color, even though the functionality of the plating is not impaired. Silvery pre-plating metals, such as tin, cadmium, lead, nickel, mercury, silver, and thallium virtually eliminate complaints based on appearance of the finally plated article.
  • Tin has been recognized as an excellent pre-plating material, and is sometimes applied by electroplating, but it is much more difficult to apply by displacement plating than is copper. If the tin plating bath is acidic, it is hard to obtain satisfactory coatings unless extremely high temperatures are used; even then plating is slow and erratic, and hydrogen embrittlement often occurs. If the tin plating bath is alkaline, either the normally acidic cleaning bath (which precedes plating) must be neutralized or the parts must be removed from the bath; besides, alkaline tin plating baths require an unduly high concentration of tin salt.
  • a metalor other electrically conductive substrate is plated by contacting the substrate with a free-flowing liquid containing ions of a dissolved salt of the plating metal, the operation being carried out in the presence of a driving metal which is less noble than either the substrate or the plating metal.
  • the driving metal is employed in finely divided form and the liquid is subjected to continuous agitation during plating, so that the driving metal particles contact substantially the entire surface to be plated.
  • the plating procedure appears to be electro-mechanical in nature, a simple cell being formed as the plating inducing driving metal is brought into mechanical contact with the surface of the conductive substrate.
  • Plating is facilitated by adjusting the pH of the solution so that the driving metal is rendered more soluble, the potential difference between the driving metal and the plating metal also promoting solution of the driving metal.
  • the plating inducing metal tends to' go into solution, it releases electrons, which then reduce the positively charged ions of the plating metal, causing the plating metal to deposit on the substrate.
  • the driving metal is provided as a solid metal powder in the plating solution
  • agitation of the solution causes the metal particles to contact all of the substrate surfaces exposed to the liquid, even where the surface geometry is quite intricate.
  • the plating continuity is on the order of completeness of displacement coatings, but, unlike displacement plating, it is not limited to extremely thin coatings.
  • This new electromechanical system should enable plating the interior of tubing substantially uniformly throughout its length.
  • Example I The following ingredients were placed in a 4-quart open-end tumbling barrel:
  • Glass beads (range from 4 mm. to about 0.1
  • the tumbling barrel (which was still hot from steam cleaning the parts) was then rotated at 50 rpm. for approximately 10 minutes, after which the liquid was dumped out of the barrel and the washers rinsed and examined. It was apparent that they had received a thin uniform tin plate, the satisfactory adherence of which was established by pressing the adhesive surface of a tacky and pressure-sensitive adhesive tape into uniform contact with the surface and removing it without stripping off any of the plated metal.
  • the washers displayed significantly greater corrosion resistance than washers which had been identically zinc plated over a conventional displacement deposited copper pre-plate.
  • Example I When Example I was repeated with the aluminum powder omitted, no tin plating whatsoever was detected.
  • the smaller the particle the less the total weight of driving metal required.
  • small aluminum particles are particularly susceptible to oxidation and may provide a smaller amount of aluminum for a given weight of powder.
  • Large driving metal particles can be used, but if the size becomes too great, the particles are unable to penetrate into some of the crevices in intricate parts; additionally the larger particles more quickly acquire a displacement-plated layer of the plating metal than do smaller particles.
  • the composition should be balanced so that the amount of metal powder is just suflicient to supply the number of electrons to reduce all the metal salt ions. If too great an excess of the metal powder is present, the powder itself tends to be displacement-plated with the metal of the metal salt. I have found that approximately 4 to 8 grams (0.15-0.30 gram mol) of IO-micron aluminum particles functions effectively with 3 grams of SnCl (i.e., approximately 1.9 grams, or 0.016 gram mol, of tin).
  • the optimum composition in a given situation should be modified in view of densities, materials, molecular weights, plating thickness, and so on.
  • the pre-plating metal salt has a lower molecular weight than SnCl or if the metal has a valence greater than 2, more aluminum will be necessary. If a powdered metal having a less tenacious oxide coating than aluminum is employed, the amount of powder may be decreased. If, on the other hand, the powdered metal has a valence lower than aluminum, more atoms of metal will be required to yield the same number of electrons.
  • 2-5 micron zinc powder is used instead of 10- micron aluminum powder, the weight necessary is only about one half as great.
  • Example II The following ingredients were mixed in a 400 ml. ibeaker:
  • Example III Example II was repeated except for the substitution of 1 gram of powdered magnesium (-l00 mesh) for the manganese and SnCl instead of SnSO Results were essentially the same.
  • Example IV Example HI was repeated, except that 1 gram of 325 mesh titanium was substituted for the powdered magnesium and a few drops of HF were added to help remove the oxide from the titanium particles. Results were substantially identical.
  • Example V Example -II was repeated, except that 1 gram of 325 mesh zinc was substituted for the powdered maganese. Results were substantially identical.
  • Example VI To a 400 ml. beaker the following ingredients were added:
  • %-inch cold rolled steel washer was cleaned in 50 ml. of a solution consisting essentially of phosphoric acid and, a; mixture of surfactants. Toa beaker containing the solution and the washer were then added 2 grams oflead fluoborate and 1 gram of 325 mesh zinc. The composition was stirred for one minute, after which time it was observed that a lead coating had formed on the washer,
  • Example VIII Example VII was repeated except that l of HgCl was substituted for the lead fluoborate. A mercury coating formed on the surface of the washer.
  • Example IX Example VII was repeated except that 1 gram of silver nit-rate was substituted for the lead fluoborate. A silver coating was formed on the washer.
  • Example X Example VII was repeated except that 1 gram of thallium chloride was substituted for the lead fluoborate. A thallium coating was formed on the washer.
  • Example XI The following ingredients were placed in a 400 ml. beaker:
  • Example XII Example XI was repated except for the substitution of a 2.” x 2" x A molybdenum template for the copper. Results were substantially identical.
  • Example XIII Example XI was'repeated except for substitution of a brass template for the copper. Results were substantially identical.
  • a previously cleaned %-inch steel washer was dropped into the composition, which was then stirred vigorously for about 1 minute. Upon removal, the washer was found to have a uniform nickel plating.
  • Powdered metal has the advantage that it is able to penetrate small nooks and crannies and provides substantially complete coverage and contact with the surface which is to be plated.
  • the driving metal is preferably chosen from other than Group I-A or II-A of the Periodic Table (especially the former), although even these alkali metals may be of use, e.g., in an ionizing solvent with which they do not react violently.
  • the relative positions of the metal of the part and the metal of the salt which is to be plated in the electrometive series do not seem to be especially critical, but, in any event, the plating inducing metal is less noble (or more active) than either of the other two.
  • the difference in oxidation potential :between the plating inducing metal and the substrate apparently need be only that necessary to overcome the resistance of the electrical circuit set up.
  • the pH of the plating bath should be controlled to minimize dissolving the part being plated, the plating, or both.
  • the pH of the plating bath should probably be at least 2.
  • a porous mechanically zinc plated part may be sealed by tumbling it in an acidified solution of a tin salt containing dispersed aluminum particles.
  • the driving meta-l may advantageously be an alloy (e.g., AlzMn, :5 A1:Zn, 45:50:5 Sn:Al:Zn, and many others) rather than a single metal.
  • the use of such alloys may permit a reduction of the amount of acid required in the solution, the presence of even minor amounts of other metals apparently reducing the tenacity with which oxide is normally attached to metals like aluminum.
  • driving metal particles and the plating metal salt may be added to the liquid individually, these materials are preferably combined in solid form in a predetermined ratio to provide the most efiicient plating coverage for the surface to be plated.
  • the driving metal particles may be pre-mixed with inhibitor (e.g., 1 or 2 drops of diethanolamine or n-tallow 1,3-propylene diamine per gram of l0-micron aluminum powder), and the salt of the plating metal and the mass pressed into a pellet.
  • inhibitor e.g., 1 or 2 drops of diethanolamine or n-tallow 1,3-propylene diamine per gram of l0-micron aluminum powder
  • Still another way is to disperse the metal powder in a solution of water-soluble gum (e.g., 5 grams of 25 micron zinc particles in 10 cc.
  • a galvanomechanical process for plating a thin continuous layer of silvery metal on each of a number of small metal parts comprising the steps of providing in a tumbling barrel water,
  • ABSTRACI Conductive substrates especially the surfaces of small ferrous metal parts, are galvanomechanically plated by contacting their exposed surfaces with a free-flowing liquid containing the dissolved salt of a plating metal, together with a driving metal which is less noble than either the substrate or the plating metal.
  • the driving metal is desirably particulate and the process is especially adapted for use in a conventional tumbling barrel.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemically Coating (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
US374151A 1964-06-10 1964-06-10 Process of plating metal objects Expired - Lifetime US3400012A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US374151A US3400012A (en) 1964-06-10 1964-06-10 Process of plating metal objects
DE19651521382 DE1521382C (de) 1964-06-10 1965-06-04 Kontaktverfahren zum Abscheiden eines silberfarbenen Metallüberzugs
CH800765A CH461914A (de) 1964-06-10 1965-06-09 Verfahren zur Aufbringung eines Metallüberzuges, Mittel zur Durchführung dieses Verfahrens und nach dem Verfahren beschichtetes Unterlagematerial
GB23090/65A GB1118312A (en) 1964-06-10 1965-06-10 Metal plating

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US374151A US3400012A (en) 1964-06-10 1964-06-10 Process of plating metal objects

Publications (2)

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US3400012A true US3400012A (en) 1968-09-03
US3400012B1 US3400012B1 (enrdf_load_stackoverflow) 1968-09-03

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US374151A Expired - Lifetime US3400012A (en) 1964-06-10 1964-06-10 Process of plating metal objects

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Country Link
US (1) US3400012A (enrdf_load_stackoverflow)
CH (1) CH461914A (enrdf_load_stackoverflow)
GB (1) GB1118312A (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3531315A (en) * 1967-07-17 1970-09-29 Minnesota Mining & Mfg Mechanical plating
FR2354390A1 (fr) * 1976-06-10 1978-01-06 Waldes Kohinoor Inc Procede non polluant pour traitements de surfaces metalliques
WO1981003292A1 (en) * 1980-05-12 1981-11-26 Minnesota Mining & Mfg Composition for mechanically depositing heavy metallic coatings
US4389431A (en) * 1980-05-12 1983-06-21 Minnesota Mining And Manufacturing Company Process for mechanically depositing heavy metallic coatings
US4654230A (en) * 1984-10-12 1987-03-31 Tru-Plate Process, Inc. Method of impact plating selective metal powders onto metallic articles
WO1988000623A1 (en) * 1986-07-17 1988-01-28 Macdermid, Incorporated Mechanical galvanizing coating resistant to chipping, flaking and cracking
WO1988003060A1 (en) * 1986-10-22 1988-05-05 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
US4800132A (en) * 1986-10-22 1989-01-24 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
US4950504A (en) * 1986-10-22 1990-08-21 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
EP0348119A3 (en) * 1988-06-23 1991-07-17 Kabushiki Kaisha Toshiba Method of processing metal connectors on semi-conductor devices
US5156672A (en) * 1990-07-13 1992-10-20 Mcgean-Rohco, Inc. Mechanical plating paste
US5762942A (en) * 1996-04-08 1998-06-09 Rochester; Thomas H. Process of mechanical plating
US20030134050A1 (en) * 2001-12-18 2003-07-17 Tatsuo Kunishi Electronic part and method for manufacturing the same
US20040043143A1 (en) * 2002-08-30 2004-03-04 Rochester Thomas H. Mechanical deposition process
US20100221574A1 (en) * 2009-02-27 2010-09-02 Rochester Thomas H Zinc alloy mechanically deposited coatings and methods of making the same
WO2011127480A1 (en) * 2010-04-09 2011-10-13 Advanced Lighting Technologies, Inc. Mechanically plated pellets and method of manufacture

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5554561A (en) * 1978-10-18 1980-04-21 Nippon Mining Co Ltd Metal plating method for powdered body by substitution method
DE2854159C2 (de) * 1978-12-15 1982-04-22 Bernd 4000 Düsseldorf Tolkmit Verfahren zum Aufbringen metallischer Überzüge auf metallische Werkstücke durch mechanisch-chemisches Behandeln der Werkstücke
DE3011662C2 (de) * 1980-03-26 1983-04-28 Bernd 5983 Balve Tolkmit Verfahren zum Aufbringen eines Aluminiumüberzuges auf metallische Werkstücke
US4618513A (en) * 1984-12-17 1986-10-21 Texo Corporation Tin plating immersion process

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2222830A (en) * 1937-10-14 1940-11-26 Monsanto Chemicals Stabilized reactive salt mixture
US2497057A (en) * 1950-02-07 Toilet bowl -gleanee
US3013892A (en) * 1959-12-09 1961-12-19 Minnesota Mining & Mfg Impact media for mechanical plating and method of using same
US3072498A (en) * 1961-02-28 1963-01-08 Texaco Inc Method of tin plating copper
US3084063A (en) * 1958-11-20 1963-04-02 Pilkington Brothers Ltd Process and apparatus for deposition of copper

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2497057A (en) * 1950-02-07 Toilet bowl -gleanee
US2222830A (en) * 1937-10-14 1940-11-26 Monsanto Chemicals Stabilized reactive salt mixture
US3084063A (en) * 1958-11-20 1963-04-02 Pilkington Brothers Ltd Process and apparatus for deposition of copper
US3013892A (en) * 1959-12-09 1961-12-19 Minnesota Mining & Mfg Impact media for mechanical plating and method of using same
US3072498A (en) * 1961-02-28 1963-01-08 Texaco Inc Method of tin plating copper

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3531315A (en) * 1967-07-17 1970-09-29 Minnesota Mining & Mfg Mechanical plating
FR2354390A1 (fr) * 1976-06-10 1978-01-06 Waldes Kohinoor Inc Procede non polluant pour traitements de surfaces metalliques
WO1981003292A1 (en) * 1980-05-12 1981-11-26 Minnesota Mining & Mfg Composition for mechanically depositing heavy metallic coatings
US4389431A (en) * 1980-05-12 1983-06-21 Minnesota Mining And Manufacturing Company Process for mechanically depositing heavy metallic coatings
US4654230A (en) * 1984-10-12 1987-03-31 Tru-Plate Process, Inc. Method of impact plating selective metal powders onto metallic articles
US4775601A (en) * 1986-07-17 1988-10-04 Macdermid, Incorporated Mechanical galvanizing coating resistant to chipping, flaking and cracking
US4724168A (en) * 1986-07-17 1988-02-09 Macdermid, Incorporated Mechanical galvanizing coating resistant to chipping, flaking and, cracking
WO1988000623A1 (en) * 1986-07-17 1988-01-28 Macdermid, Incorporated Mechanical galvanizing coating resistant to chipping, flaking and cracking
WO1988003060A1 (en) * 1986-10-22 1988-05-05 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
US4800132A (en) * 1986-10-22 1989-01-24 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
US4950504A (en) * 1986-10-22 1990-08-21 Macdermid, Incorporated Mechanical plating with oxidation-prone metals
EP0348119A3 (en) * 1988-06-23 1991-07-17 Kabushiki Kaisha Toshiba Method of processing metal connectors on semi-conductor devices
US5156672A (en) * 1990-07-13 1992-10-20 Mcgean-Rohco, Inc. Mechanical plating paste
US5762942A (en) * 1996-04-08 1998-06-09 Rochester; Thomas H. Process of mechanical plating
US20030134050A1 (en) * 2001-12-18 2003-07-17 Tatsuo Kunishi Electronic part and method for manufacturing the same
US20040043143A1 (en) * 2002-08-30 2004-03-04 Rochester Thomas H. Mechanical deposition process
US20100221574A1 (en) * 2009-02-27 2010-09-02 Rochester Thomas H Zinc alloy mechanically deposited coatings and methods of making the same
WO2011127480A1 (en) * 2010-04-09 2011-10-13 Advanced Lighting Technologies, Inc. Mechanically plated pellets and method of manufacture

Also Published As

Publication number Publication date
DE1521382B2 (de) 1972-06-15
GB1118312A (en) 1968-06-26
CH461914A (de) 1968-08-31
US3400012B1 (enrdf_load_stackoverflow) 1968-09-03
DE1521382A1 (de) 1969-11-06

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Legal Events

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B1 Reexamination certificate first reexamination