US2436690A

US2436690A - Acid chloride-fluoride bath for nickel plating

Info

Publication number: US2436690A
Application number: US582423A
Authority: US
Inventors: Rose Arthur H Du
Original assignee: Harshaw Chemical Co
Current assignee: Harshaw Chemical Co
Priority date: 1945-03-12
Filing date: 1945-03-12
Publication date: 1948-02-24
Anticipated expiration: 1965-02-24

Description

Patented Feb. 24, 1948 ACID CHLORIDE-FLUORIDE BATH FOR NICKEL PLATING Arthur H. Du Rose, Euclid, Ohio, assignor to The Harshaw Chemical Company, Elyria, Ohio, a r

, corporation of Ohio No Drawing. Application MarchlZ, 1945,

Serial No. 582,423

3 Claims. (Cl. 204-49,)

This invention relates toeleotrodeposition of nickel from high chloride solutions, and more particularly a chloride-fluoride bath omittin boric acid.

I have now discovered that the use of certain fluorides in nickel plating solutions of the high chloride type instead of the usual boric acid buifer is advantageous in respect to ductility of the resulting deposit, throwing power and freedom from pitting. The solution also remains clear at pH values above 5.0 whereas the usual bath buffered with boric acid becomes turbid. There is also a slight increase in brightness in the all chloride solution and solutions in which the nickel in solution is more than half derived from chloride.

By high chloride solutions I mean those in which at least 33 of the nickel is from chloride, the remainder from sulfate.

As is well known, all-chloride nickel plating solutions normally yield more highly stressed deposits than do solutions high in sulfate, With the advent of equipment suitable for containing the all-chloride solution there has been substantial tendency in the last few years for Workers in the art of nickel plating to experiment with solutions of the all-chloride or high-chloride type in an attempt to produce deposits no more highly stressed than those taken from the usual highsulfate solutions. Surprisingly, the use of fluorides as described below results in marked reduction in stress in the deposit. For example, a half chloride bath using fluorides gives a, deposit which is no more highly stressed than those derived from the normal high-sulfate bath. This comparison is between solutions buffered with fluoride on the one hand and with boric acid on the other, 15 to 30 grams per liter of NH4HF2 or equivalent fluorine content of other fluorides as described below compared with 37.5 grams per liter of boric acid in standard Watts bath, these being optimum concentrations in both cases. Still more surprisingly, the use of fluorides as described below gives improved results in respect to throwing power, pitting, brightness and bufiering action.

Fluorides suitable for my purpose are HF, NaF, KHFz, NHiHFz, NiFz, and NiHF. These are used in quantity between 15 and 30 grams per liter in the case of NHiHFz and in the other cases the equivalent in fluorine content of 15 to 30 grams per liter of NH4IIF2.

Suitable bath compositions are as follows:

Nickel chloride hexahydrate 33%? to 1007 .grems per liter.. 200 to Nickel sulfate hexahydrate ee%%m 0%.? v410...} 40o A substance of the class consisting of NHiHFQ, HF, NaF,

KHFi, NiFi, and NiHF and mixtures of a plurality thereof, the total fluorine content thereof being equivalent to iHFi grams per Men. 15 to 30 Water Remainder pH (may be adjusted with H01) 2.5 to 5.5

Specific examples of preferred bath proportions according to the invention are as follows:

Having thus described my invention, what I' claim is:

1. A nickel plating solution essentially consisting of water from 200 to 400 grams per liter of a source of nickel of the class consisting of (l) nickel chloride and (2) nickel chloride plus nickel sulfate, in proportion such that at least 33 of the nickel is from the chloride, HCl suiflcient to produce a pH of from 2.5 to 5, and a source of fluorine of the class consisting of NH4HF2, HF, NaF, KHFz, NiF'z, NiHE and mixtures of a plurality thereof, the total fluorine content of said source of fluorine being equivalent to from 15 to 30 grams per liter of NH4HF2.

2. A nickel plating solution essentially consist ing of water, nickel chloride, HCl suflicient to produce a pH of from 2.5 to 5, and from 15 to 30 3 grams per liter of a substance of the class consisting of NH4HF2, HF, NaF, KHFz, NiFz, NiHF and mixtures of a plurality thereof.

3. A nickel plating solution essentially consisting of water, from 200 to 400 grams per liter of 5 a source of nickel of the class consisting of (1) nickel chloride and (2) nickel chloride plus nickel sulfate in proportion that at least 50% of the nickel is from the chloride, HCl in quantity sulficient to produce a pH of 2.5 to 5, and a source of fluorine of the class consisting of; NHiHFz, HF, NaF, KHFz; NiF2,.NiHF. and mixtures of a plurality thereof, the total fluorine content of said source of fluorine being equivalent to from 15 to 30 grams per liter of NH4HF2.

ARTHUR H, DU ROSE;

REFERENCES CITED The following references-are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date Loose Mar. 16; 1943 FOREIGN PA'IEN'IS Number Country Date 513,963 Great Britain Oct. 26, 1939 OTHER REFERENCES Transactions of the Electrochemical Society, vol. '75 (1939) pages 209-211, by W. A. Wesley et al 20 Standards. Nol10l1(1924),page 50.