US3133005A - Process for electrodepositing metallic coatings - Google Patents
Process for electrodepositing metallic coatings Download PDFInfo
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- US3133005A US3133005A US74482A US7448260A US3133005A US 3133005 A US3133005 A US 3133005A US 74482 A US74482 A US 74482A US 7448260 A US7448260 A US 7448260A US 3133005 A US3133005 A US 3133005A
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- United States
- Prior art keywords
- phosphate
- coating
- aqueous solution
- electroplating
- solution
- Prior art date
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- Expired - Lifetime
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- 238000000576 coating method Methods 0.000 title claims description 28
- 238000000034 method Methods 0.000 title claims description 13
- 239000011248 coating agent Substances 0.000 claims description 25
- 229910019142 PO4 Inorganic materials 0.000 claims description 22
- 229910052751 metal Inorganic materials 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 20
- 239000000243 solution Substances 0.000 claims description 20
- 239000010452 phosphate Substances 0.000 claims description 19
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 18
- 239000007864 aqueous solution Substances 0.000 claims description 11
- 238000009713 electroplating Methods 0.000 claims description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 10
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 claims description 10
- 229910052725 zinc Inorganic materials 0.000 claims description 6
- 239000011701 zinc Substances 0.000 claims description 6
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 5
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 3
- 230000002378 acidificating effect Effects 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 230000006641 stabilisation Effects 0.000 claims description 2
- 238000011105 stabilization Methods 0.000 claims description 2
- 235000021317 phosphate Nutrition 0.000 description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 150000002739 metals Chemical class 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 4
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 4
- 229910000165 zinc phosphate Inorganic materials 0.000 description 4
- 229910001369 Brass Inorganic materials 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 239000010951 brass Substances 0.000 description 3
- 229910052793 cadmium Inorganic materials 0.000 description 3
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- -1 ferrous metals Chemical class 0.000 description 3
- 229910001385 heavy metal Inorganic materials 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 3
- 235000011121 sodium hydroxide Nutrition 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000005282 brightening Methods 0.000 description 2
- DOBRDRYODQBAMW-UHFFFAOYSA-N copper(i) cyanide Chemical compound [Cu+].N#[C-] DOBRDRYODQBAMW-UHFFFAOYSA-N 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 239000011135 tin Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- GTLDTDOJJJZVBW-UHFFFAOYSA-N zinc cyanide Chemical compound [Zn+2].N#[C-].N#[C-] GTLDTDOJJJZVBW-UHFFFAOYSA-N 0.000 description 2
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical class [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- TVQLLNFANZSCGY-UHFFFAOYSA-N disodium;dioxido(oxo)tin Chemical compound [Na+].[Na+].[O-][Sn]([O-])=O TVQLLNFANZSCGY-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- LJCNRYVRMXRIQR-OLXYHTOASA-L potassium sodium L-tartrate Chemical compound [Na+].[K+].[O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O LJCNRYVRMXRIQR-OLXYHTOASA-L 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000011006 sodium potassium tartrate Nutrition 0.000 description 1
- 229940079864 sodium stannate Drugs 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Classifications
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
Definitions
- the present invention concerns the electrolytic coating of metals, especially of ferrous metals, for the purpose of protection or decoration.
- the customary practice at present is to phosphatize the metals in order to provide them with a protection layer which in turn is covered with a finishing coat of paint or enamel.
- the metals, and especially the ferrous metals, which are phosphatized by means of diacid phosphates of heavy metals with a layer weight between 0.2 and -g./m. have proved to be particularly suitable to receive subsequently an electrolytic deposit of another metal.
- the object of the invention thus is a process of electrolytic coating of metals, especially of ferrous metals, which is particularly remarkable because it consists of phosphatizing these metals with an aqueous solution of diacid phosphate of heavy metal under such conditions that a weight of coating between 0.2 and 10 g./n1. is obtained and proceeding then by the manner which is usual for the electrolytic coating of metals that are thus phospha tized.
- the diacid phosphates of heavy metals that can be used for the stage of phosphatization are above all the diacid phosphate of Zinc and the diacid phosphate of manganese of which the first is brighter electrolytic coatings.
- phosphates in aqueous solution can be put into operation according to the usual methods of phosphatization by immersion or by spray or atomization at any temperature between the temperature of the environment and the boiling temperature of the solution.
- the metals that can be deposited on the phosphatized pieces are all those that are anodic with regard to the base metal or which are made anodic with regard to the latter through an increase of its potential by the phosphate layer.
- iron pieces one can thus deposit electrolytically zinc, nickel (mat or bright), chromium, copper, brass, tin, and cadmium which is normally not anodic with regard to the iron.
- compositions given are illustrative only and the operating conditions are specific for the given solutions-only.
- Other'oxidizing agents, concentrations .and operating conditions can be used to produce the desired 0.2-10 grams per square meter coating and, once it is rinsed in a solution having the acidity of the contemplated electroplating solution under a similar current density condition, the phosphate coated surface is prepared to receive an electrodep'osit.
- Example I G./liter Diacid zinc phosphate 18 Zinc nitrate s 7 4 Phosphoric acid .24.. 3 Sodium chlorate Y r 7.5
- Thisrbath The characteristics of thisrbath are as follows: i Free acidity points 4 to 4.8 Total acidity do 27 to 30 Temperature C 65 to Time of treatment per immersion minutes 5 to 10 The weight of the-layer obtained-is from 1.5 to 8.g./m.
- Example II V i i v G./liter Diacid zinc phosphate 7.5 Zinc nitrate 10 Phosphoric acid 3.4
- the weight of the layer obtained is from 1 to 6 g./m.
- Aiter phosphatiziation in any one of the aforementioned baths the pieces are rinsed in water, then with a diluted solution of sodium cyanide (it the bath of electrolysis is alkaline) or of hydrochloric acid (it the bath of electrolysis is acid).
- the quantity of the sodium cyanide or hydrochloric acid used in the aqueous solution was controlled so as to adjust the pH of the aqueous solution to a value approximating the pH of the subsequent electroplating solution.
- the aqueous solution containing the sodium cyanide or hydrochloric acid at the appropriate pH was contacted with the phosphated surface of the workpiece electrically charged as a cathode under a current density con -'tion-corresponding substantially to that to be employed in the subsequent electroplating step.
- Variable period of treatment Fixed at 20 minutes for the tests.
- the objects w ch are phosphatiz/ed and coated electrolytically according to the.
- the preliminary phosphatization of the pieces which are to be coated electrolytically is actually not an additional operation, for it replaces advantageously the electrolytic degreasing and the anodic attack in acid environment normally used.
- the phosphate layer which is deposited according to the invention favors a better dispersion of the lines of the current and hence a better penetration of the electrolytic deposits. (The needle effect being distributed over the whole surface of the pieces.)
- a process tor forming electrodeposited coatings on metal surfaces which comprises the steps of contacting said metal surface with an aqueous acidic phosphate coating solution selected, from the group consisting of zinc and manganese phosphate solutions to form thereon a phosphate coating having a weight in the rangeot 0.2-10 grams per square meter, thereafter contacting said phosphate coated surface as a cathode with an aqueous solution containing a soluble compound selected from the group consisting of hydrochloric acid and sodium cyanide in an amount to provide a pH of a value herein.- a-fiter defined and for a period of time sufficient to effect stabilization of said phosphate-coated surface, thereafter electroplating a metallic, coating directly on said phos: phate coating, said aqueous solution having been adjusted 3,133,005 5 6 to the approximate pH of the electroplating solution and References Cited in the file of this patent said aqueous solution being applied under approximately UNITED STATES PATENTS similar current
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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)
Description
United States Patent No Drawing. Filed Dec. 8, 1960, Ser. No. 74,482 3 Claims. (Cl. 204-38) The present invention concerns the electrolytic coating of metals, especially of ferrous metals, for the purpose of protection or decoration.
It has especially in view the improvement of this coating and the perfection of the manner in which it has been operated up till now by combining in it a stage of preliminary phosphatization.
The customary practice at present is to phosphatize the metals in order to provide them with a protection layer which in turn is covered with a finishing coat of paint or enamel.
According to the invention it has been discovered that contrary to the accepted notion according to which these phosphate layers are electrically isolating, it is possible, by an appropriate choice of the phosphatizing agents and the operating conditions, to use the phosphate coats thus formed subsequently as a layer of anchorage for electrolytically deposited metals.
Thus, according to the invention the metals, and especially the ferrous metals, which are phosphatized by means of diacid phosphates of heavy metals with a layer weight between 0.2 and -g./m. have proved to be particularly suitable to receive subsequently an electrolytic deposit of another metal.
The object of the invention thus is a process of electrolytic coating of metals, especially of ferrous metals, which is particularly remarkable because it consists of phosphatizing these metals with an aqueous solution of diacid phosphate of heavy metal under such conditions that a weight of coating between 0.2 and 10 g./n1. is obtained and proceeding then by the manner which is usual for the electrolytic coating of metals that are thus phospha tized.
The advantages of the present process compared to pre- Vious processes of electrolytic coating are considerable, as will be seen in the following, as far as the adherence of the electrolytic coating and the improvement of the corrosion resistance of this coating is concerned.
The characteristics 'of the process according to the invention will now be examined in more detail.
The diacid phosphates of heavy metals that can be used for the stage of phosphatization are above all the diacid phosphate of Zinc and the diacid phosphate of manganese of which the first is brighter electrolytic coatings.
These phosphates in aqueous solution can be put into operation according to the usual methods of phosphatization by immersion or by spray or atomization at any temperature between the temperature of the environment and the boiling temperature of the solution.
In order to obtain the desired Weight of coating one can adjust the period of contact of the metals with the solution and the oxidizing accelerating agent which is added to the latter. In this respect and although all oxidizing agents classically used as accelerators give satisfactory results it is preferred to use the nitrates or chlorates and their mixtures, and with them present in the solution the results obtained are particularly good.
normal current density, which is electrodepositing solution.
3,133,005 Patented lVlay 12, 1964 The pieces thus phosphatized aresubsequently rinsed in water, and thereafter in a solution whose pH correspondsto that of the solution to be used to form the electrolytic coating or deposition. The surfaces are then immersed in this solution with the current on so as to avoid any redissolution of the phosphate deposit in the actual The electroplating solutions may be the classical alkaline or acid electroplating solutions used under normal working conditions, except that initially one operates under a higher current density, e,'g., up to 10 times the then reducedto normal after a few seconds.
preferred because it permits The metals that can be deposited on the phosphatized pieces are all those that are anodic with regard to the base metal or which are made anodic with regard to the latter through an increase of its potential by the phosphate layer.
On iron pieces one can thus deposit electrolytically zinc, nickel (mat or bright), chromium, copper, brass, tin, and cadmium which is normally not anodic with regard to the iron.
In order to illustrate the invention in greater detail some representative examples for carrying out the present process for coating pieces of ferrous metal or of alloys of zinc or aluminum are set forth below.
It is to be understood, however, that the compositions given are illustrative only and the operating conditions are specific for the given solutions-only. Other'oxidizing agents, concentrations .and operating conditions can be used to produce the desired 0.2-10 grams per square meter coating and, once it is rinsed in a solution having the acidity of the contemplated electroplating solution under a similar current density condition, the phosphate coated surface is prepared to receive an electrodep'osit.
Example I G./liter Diacid zinc phosphate 18 Zinc nitrate s 7 4 Phosphoric acid .24.. 3 Sodium chlorate Y r 7.5
The characteristics of thisrbath are as follows: i Free acidity points 4 to 4.8 Total acidity do 27 to 30 Temperature C 65 to Time of treatment per immersion minutes 5 to 10 The weight of the-layer obtained-is from 1.5 to 8.g./m.
Example II V i i v G./liter Diacid zinc phosphate 7.5 Zinc nitrate 10 Phosphoric acid 3.4
The characteristics of this bath are as follows:
Total acidity points 20 Temperature C to G./liter Diacid manganese phosphate 48 Manganese nitrate 6 Phosphoric acid 7 3 The characteristics of this bath are as follows:
Free acidity points 9 to 11 Total acidity do 60 Temperature C 95 Period of immersion minutes 15 The weight of the layer obtained is from 2 to 10 g./m.
The weight of the layer obtained is from 1 to 6 g./m.
Aiter phosphatiziation in any one of the aforementioned baths, the pieces are rinsed in water, then with a diluted solution of sodium cyanide (it the bath of electrolysis is alkaline) or of hydrochloric acid (it the bath of electrolysis is acid). The quantity of the sodium cyanide or hydrochloric acid used in the aqueous solution was controlled so as to adjust the pH of the aqueous solution to a value approximating the pH of the subsequent electroplating solution. The aqueous solution containing the sodium cyanide or hydrochloric acid at the appropriate pH was contacted with the phosphated surface of the workpiece electrically charged as a cathode under a current density con -'tion-corresponding substantially to that to be employed in the subsequent electroplating step.
These pieces are subsequently immersed under current in any one of the following baths of electrolytic deposit depending upon the coating that one wishes to obtain.
Example V-Cadmium- Bath l Example VIII-Brass Bath Copper cyanide g./liter Zinc cyanide do 10 Sodium cyanide do 50 Sodium carbonate do 30 Density of normal current I amp./=drn. 0.3 Temperature C 20 to 30 Tension ..v 2
Variable period of treatment: Fixed at 20 minutes for the tests.
Example IXTinning Bath Sodium stannate g./ liter 80 Caustic soda do 13 Density of normal current "amp/din? 1 Tension v 4 to 6 Temperature C i p 75 Variable time: fixed at 15 minutes for the tests.
Example X-Nickeling Bath Nickel sulfate -g./liter 250 Nickel chloride do 40 Boric acid do 40 Density of normal current a1np./dm. 2 Tension v Temperature C to Variable time: Fixed at 10 minutes for the tests.
The tests described in these examples support the observation that in all the cases the adherence of the electrolytic coating is excellent. However, the deposits made on zinc phosphate according to Examples I, II and IV are brighter than on manganese phosphate according to Example HI. 7
Moreover, these tests clearly show the following advantages of the present process as compared to previous Double cadmium and sodium cyanide g./liter 40 Sodium cyanide do 30 Caustic soda do 10 Usual brightening agent do 3 Density of normal current ..a.mp./dm. 1 to 1.5 Tension v 1 to 3 Temperature of the environment. 7 Variable time: Fixed at 20 minutes for the tests.
Example VI-Zinc Bath Zinc cyanide g./liter ,60 Sodium cyanide do 42 Soda ..do.. Usual brightening agent -cm./ liter..- 20 Density of normal current .amp./dm. 3 Tension v 3 to 4 Temperature otthe environment. Variabletime: Fixed at 20 minutes for the tests.
. Example .VIl..-Copper Bath v Copper cyanide g./liter 30 Sodium cyanide do 37.5 Carbonate do 25 Caustic soda do 10 Rochelle salt do 45 Density of normal current amp./dm. 2to 3 Temperature C 50 to 55 processes of electrolytic coating. The objects w ch are phosphatiz/ed and coated electrolytically according to the.
invention show a resistance to corrosion which is much greater than that of objects which are coated simply electrolytically. Thus the pieces which were phosphatized according to any one of the Examples I to IV and cadmium-plated according to Example V and on which an initial point of corrosion was marked have resisted 288 hours in an industrial acid atmosphere as compared to 104 hours for pieces which were only cadmium-plated according to Example V and provided with an initial point of corrosion.
Besides, it should be emphasized that the preliminary phosphatization of the pieces which are to be coated electrolytically is actually not an additional operation, for it replaces advantageously the electrolytic degreasing and the anodic attack in acid environment normally used. Finally, the phosphate layer which is deposited according to the invention favors a better dispersion of the lines of the current and hence a better penetration of the electrolytic deposits. (The needle effect being distributed over the whole surface of the pieces.)
What is claimed is:
l. A process tor forming electrodeposited coatings on metal surfaces which comprises the steps of contacting said metal surface with an aqueous acidic phosphate coating solution selected, from the group consisting of zinc and manganese phosphate solutions to form thereon a phosphate coating having a weight in the rangeot 0.2-10 grams per square meter, thereafter contacting said phosphate coated surface as a cathode with an aqueous solution containing a soluble compound selected from the group consisting of hydrochloric acid and sodium cyanide in an amount to provide a pH of a value herein.- a-fiter defined and for a period of time sufficient to effect stabilization of said phosphate-coated surface, thereafter electroplating a metallic, coating directly on said phos: phate coating, said aqueous solution having been adjusted 3,133,005 5 6 to the approximate pH of the electroplating solution and References Cited in the file of this patent said aqueous solution being applied under approximately UNITED STATES PATENTS similar current density conditions as employed in said electroplating step. 2,132,438 Rflmig 00L 1938 2. A process in accordance with claim 1 wherein said 5 FOREIGN PATENTS phosphate coated metal is electroplated with a metal 345119v F i 8 19 selected firom the group consisting of zinc, nickel, chrorance May 39 mium, copper, brass, tin and cadmium. OTHER REFERENCES 3. A process in accordance with claim 1 wherein said L0 Presti: Metal Finishing, October, 1942, pages 533- phosphate coating comprises a zinc phosphate coating. 10 536.
Claims (1)
1. A PROCESS FOR FORMING ELECTRODEPOSITED COATINGS ON METAL SURFACES WHICH COMPRISES THE STEPS OF CONTACTING SAID METAL SURFACE WITH AN AQUEOUS ACIDIC PHOSPHATE COATING SOLUTION SELECTED FROM THE GROUP CONSISTING OF ZINC AND MANGANESE PHOSPHATE SOLUTIONS TO FORM THEREON A PHOSPHATE COATING HAVING A WEIGHT IN THE RANGE OF 0.2-10 GRAMS PER SQUARE METER, THEREAFTER CONTACTING SAID PHOSPHATE COATED SURFACE AS A CATHODE WITH AN AQUEOUS SOLUTION CONTAINING A SOLUBLE COMPOUND SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC ACID AND SODIUM CYANIDE IN AN AMOUNT TO PROVIDE A PH OF A VALUE HEREINAFTER DEFINED AND FOR A PERIOD OF TIME SUFFICIENT TO EFFECT STABILIZATION OF SAID PHOSPHATE-COATED SURFACE, THEREAFTER ELECTROPLATING A METALLIC COATING DIRECTLY ON SAID PHOSPHATE COATING, SAID AQUEOUS SOLUTION HAVING BEEN ADJUSTED TO THE APPROXIMATE PH OF THE ELECTROPLATING SOLUTION AND SAID AQUEOUS SOLUTION BEING APPLIED UNDER APPROXIMATELY SIMILAR CURRENT DENSITY CONDITIONS AS EMPLOYED IN SAID ELECTROPLATING STEP.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US74482A US3133005A (en) | 1960-12-08 | 1960-12-08 | Process for electrodepositing metallic coatings |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US74482A US3133005A (en) | 1960-12-08 | 1960-12-08 | Process for electrodepositing metallic coatings |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3133005A true US3133005A (en) | 1964-05-12 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US74482A Expired - Lifetime US3133005A (en) | 1960-12-08 | 1960-12-08 | Process for electrodepositing metallic coatings |
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| Country | Link |
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| US (1) | US3133005A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3308042A (en) * | 1963-06-11 | 1967-03-07 | Inland Steel Co | Electrolytic tin plating |
| US3411995A (en) * | 1965-03-15 | 1968-11-19 | Enthone | Process and product for plating on cast,malleable,carburized and carbonitrided irons |
| US4319967A (en) * | 1979-11-01 | 1982-03-16 | Bell Telephone Laboratories, Incorporated | Fabrication of palladium anode for X-ray lithography |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2132438A (en) * | 1933-12-11 | 1938-10-11 | American Chem Paint Co | Method of coating metal |
| FR845119A (en) * | 1938-10-24 | 1939-08-11 | Internat Incorrodible Metal Co | Process for the surface treatment of iron and steel |
-
1960
- 1960-12-08 US US74482A patent/US3133005A/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2132438A (en) * | 1933-12-11 | 1938-10-11 | American Chem Paint Co | Method of coating metal |
| FR845119A (en) * | 1938-10-24 | 1939-08-11 | Internat Incorrodible Metal Co | Process for the surface treatment of iron and steel |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3308042A (en) * | 1963-06-11 | 1967-03-07 | Inland Steel Co | Electrolytic tin plating |
| US3411995A (en) * | 1965-03-15 | 1968-11-19 | Enthone | Process and product for plating on cast,malleable,carburized and carbonitrided irons |
| US4319967A (en) * | 1979-11-01 | 1982-03-16 | Bell Telephone Laboratories, Incorporated | Fabrication of palladium anode for X-ray lithography |
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