US2792341A - Process for electrodeposition of platinum - Google Patents

Process for electrodeposition of platinum Download PDF

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Publication number
US2792341A
US2792341A US550632A US55063255A US2792341A US 2792341 A US2792341 A US 2792341A US 550632 A US550632 A US 550632A US 55063255 A US55063255 A US 55063255A US 2792341 A US2792341 A US 2792341A
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Prior art keywords
platinum
bath
deposition
rate
metal
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Expired - Lifetime
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US550632A
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English (en)
Inventor
Atkinson Ralph Hall
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Huntington Alloys Corp
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International Nickel Co Inc
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Priority to BE553097D priority Critical patent/BE553097A/xx
Priority to NL110968D priority patent/NL110968C/xx
Priority to NL212633D priority patent/NL212633A/xx
Priority to US550632A priority patent/US2792341A/en
Application filed by International Nickel Co Inc filed Critical International Nickel Co Inc
Priority to GB35478/56A priority patent/GB838350A/en
Priority to FR1171360D priority patent/FR1171360A/fr
Priority to CH357603D priority patent/CH357603A/fr
Priority to DEM32535A priority patent/DE1052771B/de
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Publication of US2792341A publication Critical patent/US2792341A/en
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    • 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
    • C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals

Definitions

  • the present invention relates to the electrodeposition of platinum andmore particularly to the production, of thick, smooth, commercially acceptable electrodeposits of platinum from an acid chloride electrolyte- It has been well known that thin, adherent. electroe deposits of platinum may be obtainedby electrolyzing a variety of baths. These thin deposits, as obtained-db rectly from the baths, have been of .the orderof. 0.00001 inch to rarely 0.001 inch in thickness. Thereareseveral main classes of baths from which these decorativeplates are obtained. Roseelles bath is anexample of .oneclass. This bath contains an aqueous solution. of a complex platino phosphate usually modified with suitable buffering and brightening agents.
  • Another. classof thesedecorative plating baths is the type using ammoniacal dinitro-diammino platinum as a source of the metal to betdeposited. Good throwing power together with bright thin deposits are characteristic of this type of.bath..
  • the cathode current density may be higher thanthatused with Roseliv bath.
  • the third main. class of these baths is the alkali platinatetype. The-platinate .issusu-i ally buifered and stabilizedby the addition. of. walks.- line oxalate.
  • thisbath achieves a cathode efliciency, with respect to platinum, of almost 100%.
  • the typical deposits are very bright when thin and .the throwingpower of the solutionistgood-
  • Eachofi the aforementioned baths may be usedlinxadiaphragm. cell.
  • Kushner Metal Industry, 19-39, page 131 declares that deposits from acidchloride baths are spongy, dark or non-adherent. To my knowledge, no satisfactory ductile platinum electrodepositshave been obtained when using the acid chloride bathunder conditions which will efficiently corrode massiveplatinum anodes.
  • Another. object of the invention is to provide a process bymeans of which thick, smooth, ductile electrodeposits of platinum may be made'without intermediate'brushing or polishing operations.
  • the invention also contemplates providing a process utilizing a stable'bath'suitable for the production of thick, smooth, ductile-'- electrodeposits of platinum wherein the concentration; of. the platinum in the electrolyte will remainiwithin operating specifications.
  • the present invention 'contemplates a process for the production of thick, smooth electrodepositsiof platinum from an aqueous bath which containsinsolution' between about 180 and about 300 grams perliter (g. p. l.) of hydrogen chloride and between about lO and about 50 g. p. l. of platinum.
  • the minimum rate of deposition with which thick, smooth adherent deposits may be obtained is about ()..”*l8 l0- inch per hour. Again, if the concentration of hydrogen chloride is lowered still further, to say 180 g. p. 1., then a minimum rate of deposition of about 0.59X 10- inch per hour is necessary in order to obtain thick, smooth adherent deposits. At all of these aforementioned concentrations of hydrogen chloride, the maximum rate of deposition with which one can obtainthick, smooth adherent deposits is about 1.0O l inch per hour. Table I illustrates the permissive maximum and minimum values for the rate of deposition which may be used at selected concentrations of hydrogen chloride if one 4 plenishment thereof either from the anolyte or from some external source.
  • the bath from which the metal is deposited is an aqueous acid chloride-chloroplatinate bath which must contain in solution between about 10 and about 50 g. p. l. of platinum.
  • the platinum is added to the bath initially in the form of chloroplatinic acid. If platinum metal is used as an anode, the concentration of the platinum will be maintained substantially constant during the plating operation due to solution of the metal from the anode.
  • the initial addition of platinum in the form of chloroplatinic acid. is recommended because of the convenience of the preparation of this compound. However, if one wishes, the platinum may be added in any form which will produce a solution which is free from materials which will have desires to obtain deposits which are not only thick, smooth and adherent but are also ductile.
  • the factor of rate of deposition is not equivalent to the cathode current density which is the usual criterion of the electrodepositing art. There is no simple relationship between these two factors when depositing platinum metal from the electrolytev contem plated in this invention.
  • the proper rate of deposition must be initially determined by measurement of the change in thickness of the deposit with respect to time.
  • the proper rate of deposition of metal is obtained in accordance with the inventiomthe rate may then be maintained by control of the particular conditions (e.
  • the cell may be constructed of any material resistant to corrosion by the electrolyte. It may be of a diaphragm or a non-diaphragm type.
  • the diaphragm may be of the usual type and, as those skilled in the art know, it must be resistant to the action of the electrolyte but must permit the passage of the electrical current. It is within the scope of the invention to use either soluble platinum metal anodes or insoluble anodes made from material inert to the action of the electrolyte (e. g., rhodium).
  • soluble platinum metal anodes or insoluble anodes made from material inert to the action of the electrolyte (e. g., rhodium).
  • these materials are called subversive materials.
  • titanium, zirconium, etc. should be absent from the bath because the hydrolysis products of these metal ions may be insoluble substances, colloidal in nature, which would tend to co-deposit with the platinum thus impairing the adherence, continuity and ductility of the deposit. Tungsten and molybdenum should be absent from the bath.
  • These metals represent a class of metallic elements which will form insoluble acids in strongly acidified solutions, e. g., tungstic and molybdic acids.
  • Potassium, ammonium, cesium, rubidium, etc., ions should be substantially 7 absent from the bath because of the well known tendency of these materials to cause the precipitation of platinum as the chloroplatinate, e. g., potassium chloroplatinate.
  • Metals which may co-deposit under the process conditions should be absent from the bath in appreciable quantities. For example, nickel, iron, copper, silver, gold etc., should be absent. It must be understood, however, that impurities normally associated with commerical plati'num in quantities normally occurring in commerical grades of platinum do not have any noticeable elfect on the character of the deposits.
  • platinum may be added to the bath not only in the preferred form of chloroplatinic acid but also in the form of any one or a plurality of compounds including sodium chloroplatinate, lithium choloroplatinate, alkaline earth chloroplatinates, hydrated platinic oxide and mixtures of chloroplatinitic acid and chloroplatinous acid containing less than about 5% of chloroplatinous acid.
  • platinum is added to the bath in any of the forms noted herein,
  • the--bath may tolerate up to, about 50, g. ,p; l.. in the aggregateof inertingredients, (e; g.,.the:soluble-sulfates and acetates. of ,sodium, lithium, alkaline earth; metals, magnesium, aluminum, etc.). Included: in these inert ingredients and .in the aggregate permissive upperlimits of. concentration are free sulfuric. and; acetic acids. As far;as is:known, the'addition ofmoderate.
  • base metals such as irom- 'copper, nicke1,1zinc; silver; etc.
  • Particular attention should be paid to the surface preparation of the cathode prior to plating these strikes: in order to obtain optimum adherence ofthe strike.
  • the strike should be of such a thickness as to effectively reduce the corrosionrateeven in theabsence oficathodic protection;
  • the electrolyte was placed in a glass container, center portion of the bottom of which was heated, and the temperature was brought to and maintained at 70 C.
  • the cathode was a pure platinum wire 2 inches in length and 0.044 inch in diameter which had been previously cleaned with alkaline cleaning solution and then rinsed thoroughly with distilled water.
  • Thea anodes were: two: strips: of pure platinum, each 5 inches :byi 0;5:.-inch :by :0.0.l0 inch in dimension with about 1.75; inches: immersed in the: electrolyte.
  • a potential was applied. to the system. in order to efiect a rateof deposition approximating, 0.5.)(107 in./hr..
  • the current which wasrused was..0.05-5. ampere.
  • the entire deposit was smooth, adherent and gray in color and was ductile as-indi'cated by a-cold rolling test with 20% cold" reduction as the criterion.
  • The. deposit, as plated, hadian-average-Knoop'Hardness Number (K. N.)' of 220 using a 25' gram load.
  • the plating solution was stable and had aneffective life of at least 57 plating hours-with only infrequent additions of hydro;- clilorieacid"and-waternecessary to replace losses dueto evaporation:
  • Example -II A. bath, with the same. hydrogen chloride concentra: tion as in Example I and having. a. concentration 01321.8 g..p. l. of platinum, as. chloroplatinic,acidwas,used to deposit platinum, onv a. platinum. strip cathode. measuring 1 inch by 0.25,. inch by.0.0,10 inch, Anodes, similar to those. in. Example I were also used. Using a rate of deposition of .about.0,6 10- in./hr. metal-was electrodeposited and. after, six hours at, an operatingv tempera; tureof 70 C. a deposit 3,.63X 1.0.? inch thick was .oh tained. The.
  • the resulting deposit was uniform, ductile,adherent and hadan, average-.hardnessofi 214 K. H. N. witha 25 gram load.
  • Example 111' A glass container was separated into anodicand cathodic compartments through the use of a porous porcelain diaphragm. Asolution similar to that used in Example I was placed in the cathodic compartment. A hydrochloric acid electrolyte was used as the anolyte. The anodes and cathode were similar to those used in Example I and the operating temperature was 70 C. A rate of deposition ofapproximately 0.7)(10- in./hr. was established and after one hour, 0.6,'7 l.0- inch of metal was deposited usinga current of 0.045 amp. and :1 current density of; 2.6- amps./dm.
  • Thedeposit was light gray in color, smooth, adherent and free from cracks as plated.
  • a further deposit at approximately the same rate of deposition was made on the same cathode, and after another hour the deposit was found to have increased in thickness to l.35j l0'- inch.
  • a current of 0.040 amp. with a cathode current density of 2.3 amps./ dm was used forthis secondhour.
  • the total deposit was smooth and ductile and had an average hardness of 194 K. H. N. with a 25 gram load. Chemical analysis of the catholyte revealed that its platinum content was reduced from 23 down to 15 g. p. l. in the. course. of two hours plating in. the absence of replenishment.
  • Example IV A, plating solution, was prepared. having a platinum concentration. of.22.g. p. l. and ahydrogen chloride concentration of 219 g. p. 1. It was placed in a glass con: tainer similar to the one used in Example I and heated to about 70 C. in the same manner as in Example I.
  • the cathode was a platinum wire having the same di mensions as the cathode in Example I. This cathode was previously cleaned in alkaline cleaning solution and thoroughly rinsed in distilled water.
  • the anodes were the same as used in Example I.
  • a potential was applied to the system in order to effect a rate of deposition approximating 0.9X10" in./ hr. The current which was used was 0.063 amp.
  • Example V A plating solution was prepared having a platinum concentration of 23.6 g. p. l. and a hydrogen chloride concentration of about 260 g. p. l.
  • the cathodes, anodes and cell were similar to those used in Example I.
  • a temperature of about 45 C. was attained and maintained.
  • a potential was applied to the system in order to effect a rate of deposition approximating 0.5X10" in./hr. After one hour, it was determined that the metal deposited was 0.49 10'- inch thick.
  • the current employed was 0.035 amp. and the cathode current density was 2.0 amps/dmfi.
  • Visual examination revealed that the plate was a light gray mat. On microscopic examination the plate was found to be free from cracks.
  • the average Knoop Hardness Number with a 25 gram load was 241 and the plate was found to be ductile upon a 20% cold rolling reduction.
  • the following test was conducted to illustrate the efiect of using a rate of deposition which, when plotted against the hydrogen chloride concentration, results in a point that lies outside the area FGHEF in the drawing.
  • a plating solution was prepared con taining 222 g. p. l. of hydrogen chloride and 22 g. p. l. of platinum.
  • the plating run was made at a temperature of 70 C. for three hours with a current of 0.045 amp. and a cathode current density of 2.5 amps./dm.
  • the rate of deposition was 0.27 10- in./hr.
  • the deposit 0.80 10- inch thick was found to be smooth, dark gray with slight sheen, hard and brittle. Microexarnination revealed that the deposit was cracked as plated.
  • the present invention provides a process for the production of thick, smooth ductile electrodeposits of platinum.
  • deposits up to about 0.02 inch in thickness are readily obtained.
  • the process involves electrolyzing the bath under stated conditions of rate of metal deposition correlated to hydrogen chloride concentration.
  • the essential ingredients of the bath are an aqueous solution of hydrogen chloride and a source of chloroplatinic ion.
  • the platinum in this bath is associated with chlorine such that the ratio of platinum in the chloroplatinic form to platinum in the chloroplatinous form is at least about 20:1.
  • the balance of the bath is essentially water. However, the inclusion of 0 to about 50 g. p. l.
  • soluble non-subversive inert substances e. g., sodium salts, lithium salts, sulfuric acid, acetic acid, alkaline earth metal salts, etc. is contemplated within the meaning of the term balance essentially.
  • a process for the production of thick, smooth, adherent electrodeposits of platinum free from cracks in the as-plated condition which comprises establishing an aqueous acid chloride-chloroplatinate bath containing in solution about 180 to about 300 grams per liter of hydrogen chloride, about 10 to about 50 grams per liter of platinum to provide a source of chloroplatinic ion, the balance being essentially water and electrodepositing platinum from said bath while maintaining the bath at a temperature between about 45 C. and about 90 C. at such a rate of deposition that the rate of deposition of the metal on the cathode when plotted against the concentration of hydrogen chloride in the bath will be represented by a point lying within the area FGHEF in the accompanying drawing.
  • a process for the production of thick, smooth adherent, ductile electrodeposits of platinum free from cracks in the as-plated condition which comprises establishing an aqueous acid chloride-chloroplatinate bath containing in solution about 215 to about 300 grams per liter of hydrogen chloride, about 10 to about 50 grams per liter of platinum to provide a sorce of chloroplatinic ion, the balance being essentially water and electrodepositing platinum from said bath while maintaining the bath at a temperature between about 45 C. and about C. at such a rate of deposition that the rate of deposition of the metal on the cathode when plotted against the concentration of hydrogen chloride in the bath will be represented by a point lying within the area ABCDEA in the accompanying drawing.

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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 And Plating Baths Therefor (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
US550632A 1955-12-02 1955-12-02 Process for electrodeposition of platinum Expired - Lifetime US2792341A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BE553097D BE553097A (enrdf_load_stackoverflow) 1955-12-02
NL110968D NL110968C (enrdf_load_stackoverflow) 1955-12-02
NL212633D NL212633A (enrdf_load_stackoverflow) 1955-12-02
US550632A US2792341A (en) 1955-12-02 1955-12-02 Process for electrodeposition of platinum
GB35478/56A GB838350A (en) 1955-12-02 1956-11-20 Improvements relating to the electrodeposition of platinum
FR1171360D FR1171360A (fr) 1955-12-02 1956-11-30 Perfectionnements aux dépôts électrolytiques de platine
CH357603D CH357603A (fr) 1955-12-02 1956-12-01 Procédé pour le dépôt électrolytique du platine
DEM32535A DE1052771B (de) 1955-12-02 1956-12-01 Verfahren zum elektrolytischen Abscheiden von Platin

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US550632A US2792341A (en) 1955-12-02 1955-12-02 Process for electrodeposition of platinum

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US (1) US2792341A (enrdf_load_stackoverflow)
BE (1) BE553097A (enrdf_load_stackoverflow)
CH (1) CH357603A (enrdf_load_stackoverflow)
DE (1) DE1052771B (enrdf_load_stackoverflow)
FR (1) FR1171360A (enrdf_load_stackoverflow)
GB (1) GB838350A (enrdf_load_stackoverflow)
NL (2) NL110968C (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3267009A (en) * 1962-10-08 1966-08-16 Engelhard Ind Inc Electrodeposition of platinum containing minor amounts of bismuth
US3305457A (en) * 1965-08-09 1967-02-21 Hyman Edward Sidney Hydrocarbon detection
US3351541A (en) * 1965-01-19 1967-11-07 Gen Electric Electrodeposition of the platinum metals
US6306277B1 (en) 2000-01-14 2001-10-23 Honeywell International Inc. Platinum electrolyte for use in electrolytic plating
US20070089994A1 (en) * 2005-10-26 2007-04-26 Zhou Dao M Platinum electrode surface coating and method for manufacturing the same
US20080076007A1 (en) * 2002-04-11 2008-03-27 Zhou Dao M Catalyst and a Method for Manufacturing the Same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3267009A (en) * 1962-10-08 1966-08-16 Engelhard Ind Inc Electrodeposition of platinum containing minor amounts of bismuth
US3351541A (en) * 1965-01-19 1967-11-07 Gen Electric Electrodeposition of the platinum metals
US3305457A (en) * 1965-08-09 1967-02-21 Hyman Edward Sidney Hydrocarbon detection
US6306277B1 (en) 2000-01-14 2001-10-23 Honeywell International Inc. Platinum electrolyte for use in electrolytic plating
US6521113B2 (en) 2000-01-14 2003-02-18 Honeywell International Inc. Method of improving the oxidation resistance of a platinum modified aluminide diffusion coating
US20080076007A1 (en) * 2002-04-11 2008-03-27 Zhou Dao M Catalyst and a Method for Manufacturing the Same
US20070089994A1 (en) * 2005-10-26 2007-04-26 Zhou Dao M Platinum electrode surface coating and method for manufacturing the same
US10378119B2 (en) * 2005-10-26 2019-08-13 Second Sight Medical Products, Inc. Platinum electrode surface coating and method for manufacturing the same

Also Published As

Publication number Publication date
NL212633A (enrdf_load_stackoverflow)
CH357603A (fr) 1961-10-15
DE1052771B (de) 1959-03-12
GB838350A (en) 1960-06-22
NL110968C (enrdf_load_stackoverflow)
FR1171360A (fr) 1959-01-26
BE553097A (enrdf_load_stackoverflow)

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