Platinum Electrolyte

Abstract

The present invention is directed toward a platinum electrolyte which contains certain additives, and to a method for the electrolytic deposition of a platinum layer with the aid of the electrolyte according to the invention.

Claims

1-8. (canceled)

9. An aqueous, cyanide-free electrolyte for the deposition of platinum or platinum alloys on electrically conductive substrates, wherein the electrolyte has one or more ions from the group consisting of Ir, Bi, Sb, Se, and Te, and does not contain hydrochloric acid, wherein Bi, Sb, Se, and Te are present in a concentration of up to 100 mg/l of electrolyte; Ir is present in a concentration of up to 1000 mg/l of the electrolyte; and the electrolyte has platinum sulfamate complexes and said electrolyte has a pH of <2.

10. The electrolyte according to claim 9, wherein the electrolyte does not contain citric acid.

11. A method for depositing a platinum or platinum alloy layer on an electrically conductive substrate, which comprises contacting the electrolyte according to claim 9 with an anode and the substrate to be coated as cathode, and providing a current flow between the anode and the cathode.

12. The method according to claim 11, wherein the temperature of the electrolyte during deposition is 20-90? C.

13. The method according to claim 11, wherein the deposition is performed in continuous systems.

14. The method according to claim 11, wherein the current density during deposition is between 0.5-50 A/dm.sup.2.

Description

EXAMPLES

[0043] The electrolyte preparations for the depositions were implemented as follows. First, 400 ml of deionized water was put into a 1 l beaker. Then, under intensive stirring, the corresponding quantity of acid, the quantity of platinum, the wetting agent, and finally the corresponding additive were added. This solution was then topped up with deionized water to the final volume of 1 l. Brass sheets measuring 0.2 dm.sup.2, which had been pre-coated with nickel and gold, were coated under movement of electrolyte and product. The depositions took place over a current density range of 1-20 A/dm.sup.2. Particle formation in the electrolyte was assessed. The results were recorded in the following table.

TABLE-US-00001 Acid Platinum Wetting Metal No. Acid [ml/l] Platinum [g/l] agent Metal [mg/l] Anodes Temperature 1 A/dm.sup.2 2 A/dm.sup.2 5 A/dm.sup.2 10 A/dm.sup.2 15 A/dm.sup.2 20 A/dm.sup.2 1 H2SO4 100 H2[Pt(NH2SO3)2SO4] 10 5 MMO 55 1 2 2 2 2 2 2 H2SO4 50 [Pt(NH3)2(NH2SO3)4] 12 5 Antimony(III) fluoride 20 MMO 50 0 0 0 1 2 2 3 H2SO4 50 H2[Pt(NH2SO3)4] 12 2 Antimony(III) chloride 10 Pt/Ti 50 0 0 0 0 1 1 4 CH4O3S 100 H2[Pt(NH2SO3)2SO4] 5 10 Antimony(III) oxide 5 MMO 70 0 0 0 0 0 1 5 H3PO4 100 H2[Pt(NH2SO3)2SO4] 8 4 Sodium antimony(III) 15 Pt/Ti 70 0 0 0 1 1 2 oxide tartrate 6 H2SO4 10 H2[Pt(NH2SO3)2Cl2] 15 15 Bismuth(III) oxide 10 Pt/Ti 40 0 0 0 0 1 1 7 H3PO4 10 H2[Pt(NH2SO3)2SO3] 7 12 Bismuth(III) hydroxide 15 Pt/Ti 40 0 0 0 0 0 1 8 H2SO4 20 [Pt(NH3)2(NH2SO3)2] 9 6 Bismuth (III) fluoride 20 MMO 55 0 0 0 0 1 1 9 H2SO4 20 H2[Pt(NH2SO3)2SO3] 6 8 Bismuth(III) chloride 15 MMO 55 0 0 0 0 0 1 10 H3PO4 25 H2[Pt(NH2SO3)4] 12 12 Bismuth(III) bromide 5 MMO 60 0 0 0 0 1 1 11 CH4O3S 25 [Pt(NH3)2(NH2SO3)2] 8 10 Bismuth(III) iodide 5 Pt/Ti 70 0 0 0 0 0 1 12 CH4O3S 10 H2[Pt(NH2SO3)4] 10 12 Bismuth (III) 10 MMO 55 0 0 0 0 0 1 methanesulfonate 13 CH4O3S 15 [Pt(NH3)2(NH2SO3)2] 14 5 Bismuth(III) nitrate 15 Pt/Ti 55 0 0 0 0 1 1 14 H3PO4 20 H2[Pt(NH2SO3)2SO3] 5 6 Bismuth (III) tartrate 10 Pt/Ti 40 0 0 0 0 0 1 15 H2SO4 70 H2[Pt(NH2SO3)2Cl2] 8 10 Bismuth(III) citrate 5 Pt/Ti 40 0 0 0 0 0 1 16 H3PO4 70 H2[Pt(NH2SO3)2SO4] 12 5 Ammonium bismuth 5 MMO 45 0 0 0 0 0 1 citrate 17 H3PO4 50 [Pt(NH3)2(NH2SO3)2] 12 2 Selenic acid 30 MMO 60 0 0 0 1 1 2 18 H3PO4 100 H2[Pt(NH2SO3)2SO3] 12 6 Selenocyanate 10 MMO 60 0 0 0 0 1 1 19 CH4O3S 100 [Pt(NH3)2(NH2SO3)2] 15 3 Tellurocyanate 20 MMO 60 0 0 0 0 1 1 20 CH4O3S 55 [Pt(NH3)2(NH2SO3)2] 15 10 Selenate 10 Pt/Ti 65 0 0 0 0 1 2 21 H2SO4 25 [Pt(NH3)2(NH2SO3)2] 10 8 Iridium sulfate 500 MMO 55 0 0 0 0 0 1 22 H2SO4 40 H2[Pt(NH2SO3)2SO4] 8 12 Potassium tellurite 5 MMO 65 0 0 0 0 0 1 23 H2SO4 35 [Pt(NH3)2(NH2SO3)2] 5 15 Antimony(III) chloride 5 MMO 70 0 0 0 0 1 1 24 H3PO4 40 [Pt(NH3)2(NH2SO3)2] 5 3 Sodium antimony(III) 5 MMO 70 0 0 0 0 1 1 oxide tartrate 25 H3PO4 35 H2[Pt(NH2SO3)2Cl2] 5 4 Bismuth(III) bromide 10 MMO 55 0 0 0 0 0 1 26 H2SO4 60 H2[Pt(NH2SO3)2SO3] 15 6 Selenocyanate 15 Pt/Ti 60 0 0 0 0 1 2 27 H2SO4 80 H2[Pt(NH2SO3)2SO4] 14 12 Selenocyanate 10 Pt/Ti 55 0 0 0 0 1 2 28 H2SO4 80 [Pt(NH3)2(NH2SO3)2] 12 11 Sodium antimony(III) 15 Pt/Ti 40 0 0 0 0 1 1 oxide tartrate 29 CH4O3S 80 H2[Pt(NH2SO3)2SO4] 15 15 Bismuth (III) tartrate 10 MMO 45 0 0 0 0 0 1 30 CH4O3S 100 [Pt(NH3)2(NH2SO3)2] 8 12 Potassium tellurite 10 Pt/Ti 70 0 0 0 0 0 1 31 H3PO4 100 [Pt(NH3)2(NH2SO3)4] 6 5 Tellurocyanate 5 MMO 60 0 0 0 0 0 1 32 H3PO4 45 [Pt(NH3)2(NH2SO3)4] 10 2 Ammonium bismuth 5 MMO 45 0 0 0 0 0 1 citrate 33 H3PO4 90 H2[Pt(NH2SO3)4] 10 2 Tellurocyanate 20 MMO 55 0 0 0 0 1 1 34 CH4O3S 90 H2[Pt(NH2SO3)4] 7 7 Antimony(III) chloride 50 Pt/Ti 55 0 0 0 0 1 2 35 H2SO4 40 H2[Pt(NH2SO3)2SO4] 10 5 Iridium chloride 200 MMO 60 0 0 0 0 0 1 36 H2SO4 20 H2[Pt(NH2SO3)2SO3) 6 8 Hexabromoiridate 100 MMO 55 0 0 0 0 0 1 37 CH4O3S 30 [Pt(NH3)2(NH2SO3)2] 9 5 Bismuth(III) tartrate 15 Pt/Ti 60 0 0 0 0 0 1 38 CH4O3S 30 [Pt(NH3)2(NH2SO3)4] 12 15 Bismuth(III) 10 MMO 70 0 0 0 0 0 1 methanesulfonate 39 H2SO4 25 [Pt(NH3)2(NH2SO3)2] 10 8 Potassium tellurite 5 MMO 70 0 0 0 0 1 1 40 H2SO4 10 [Pt(NH3)2(NH2SO3)4] 5 5 Antimony(III) chloride 5 MMO 70 0 0 0 0 1 2 41 H2SO5 20 [Pt(NH3)2(NH2SO3)4] 20 5 Iridium iodide 50 MMO 60 0 0 0 0 1 1 Particle formation: 2 = strong, 1 = weak, 0 = none (minimal)

[0044] It was shown that, compared to Experiment 1 (no additive), the particle formation with the additive in the electrolyte was significantly minimized during the depositions.