US1564414A

US1564414A - Cadmium plating

Info

Publication number: US1564414A
Application number: US742073A
Authority: US
Inventors: Clayton M Hoff
Original assignee: Grasselli Chemical Co
Current assignee: Grasselli Chemical Co
Priority date: 1924-10-06
Filing date: 1924-10-06
Publication date: 1925-12-08
Anticipated expiration: 1942-12-08

Description

Patented lDec. 8 1925. V

UNITED STATES CLAYTON H. HOFF, OF CLEVELAND, OI IIO. ASSIGNOB TO THE GRASSEILI CHEMICAL I 1,564,414 PATENT OFFICE.

OOMZPANY, OF CLEVELAND, OHIO, A CORPORATION. 01 OHIO.

cnmmm rmrnve.

No Drawing.

To all whom it may concern:

Be it known that I, CLAYTON M. Horr, a

citizen of the United-States, residing at Cleveland, in the county of Cuyahoga and i 5 State of Ohio, have invented certain new and useful Improvements in Cadmium Plating, of which the following is a specification.

Thisinvention relates to the electroplat- 1 ing of cadmium and more particularly to a composition for that vpurpose.

In my application Serial No. 686,898,- filed Jan. 17 1924. I have disclosed a process of electroplating cadmium involving the use of an alkaline bath containing chemical combinations of cyanide, ammonium and cad mium, with or without addition agents such as gulac which may be prepared for instance by dissolving cadmium oxid or hydroxid or a salt such as cadmium sulfate in. aqua- 20 ammonia and adding thereto a soluble cyanide such as sodium cyanide.

Such .a bath is characterized by the fact that .from it pure, smooth and uniform de posits of cadmium may be producedrapidly and quantitatively if des1red,j even when the bath contains other metals such as zinc.

, It is desirable for the chemicals manufac-'v turer to be able to supplythe electroplater with the materials required ready for use,

but since itis not feasible to ship and-store the finished electro lating bath, it is one tomary when possib e to supply the electroplate'r with a mixture of chemicals ready to be dissolved in water to produce the bath. It isIt-herefore', an object of my present invention'to provide a dry mixture of chemi 'cals suitable ior storage and shipment which when dissolved in .water, with or without other materials as will appear hereinafter,

4 will give a cadmium lating bath having in gene'rai the characteristics of the bath disclosed'in my ap lication above referred to. In the courseto my investigations in this connection for the pur ose of develo 'ing' quch a dry mixture in chemicals I ave ound that baths having-the desired characteristics may be prepared "in a variety of ways.

As stated above the bath of my earl er 9 application comprises as; essential ingredients or-components cadmium, ammonium. c anide and an alkaline agent. Each of t ese components. may be suppliediin various forms. For instancethe cadmium vcom- I l6 ponent may be supplied in the formy of the kali metals. T

my invention.

Application filed Qotobera, 1924. Serial mynama foxid, h droxid, or cyanide, or in the form of a sa t such as the sulfate. The cyanide com onent may besup lied in chemical com ination with the ca ium as cadmium cyanide or as ammonium cyanide, or as other metal cyanides, preferably those of the ale ammonium component ma besupplied in the form of ammonium hy roxide or as a salt such as ammonium cyanide or sulfate. The ammonium component apparently serves as the agent which prevents or tends to prevent the deposition of other metals, particularly zinc, along with the cadmium and may be replaced by other materials 'such as sodium sulfate and other alkali metal salts. The alkaline reaction of .the bath may be produced by.

the use of ammonia or an alkali metal hydroxid. The bath referably is made to contai'nalso a colloi agent, which tends to such as starch, gulac, dextrine, etc.

The following examples ofbath compositions illustrate my inyention;

Example 3 oz., cadmium hydroxide, 6 to 7 oz., sodium cyanide: to 1 oz., caustic soda: to oz., sodium carbonate, and 1 oz., aqua ammonia" 26 B.- to each gallon of water; p

Ewample 2.

ing cadmium, cyanide. ammonium or another agent whihtends to prevent the codeposition of. other metals such as zinc with 'or'witho'ut an addition ag'enti'such as gulac may be produced in a-great variety of Ways, that is'bv the use of a great-variet of chemicals; The relative proportionsof the ingredients and the concentration of thegbath may of coursebe varied without departing from Of the great variety of combinations chemicals indicated .a bo ve' only a vconi paratively few are well adapted from-an improve the quality ofthe cadmium plate,

.or since the shipment of caustic soda and cyanide is somewhat objectionable, the electroplater may be supplied withv a mixture of cadmium hydroxide, ammoniumsulfate and gulac with directions as to the quantity thereof to be dissolved in a given quantity of water along with caustic soda and sodi-um cyanide separately supplied. Or the electroplater maybe supplied with a dry mixture of cadmium hydroxide, sodium hydroxide,

I sodium cyanide and gulac, to which ammonia or an ammonium salt is to be added in the preparation of the bath. These few examples as given are suflicient for the purposes of illustration, it being understood that the invention is not limited to the particular combinations of chemicals instanced.

The electroplating from baths comprising the combinations of chemicals described may be carried out as disclosed in my prior application, for instance at room temperature using a potential of 4 to 6 volts and a current density of l ampere per 100 square centimeters between electrodes spaced about 15 centimeters apart, and preferably using cadmium anodes with an anode surface area equal'to two or three times the cathode sur- .face area. Known expedients such as agitation or clrculatlon or heating or cooling of the bath, rotation of the electrodes, etc., may be. employed.

I claim: a

1. A composition adapted for use in the electrodeposition of cadmium comprising a cadmium compound, a material which tends to prevent the co-plating of zinc with cadmium, an alkaline agent, a cyanide, and a material'which tends to improve the quality of cadmium platings.

.2. A composition adapted for use in the electrodeposition of cadmium comprising a cadmium compound, a material which tends to prevent the co-plating of zinc with cadmium,an alkaline agent and a cyanide.

pound, a caustic alkali, and an alkali metal cyanide.

5. A composition adapted for use in the electrodeposition of cadmium comprising cadmium hydroxide, an ammonium compound, an alkaline agent and a cyanide.

6. A composition adapted for use in the electrodeposition of cadmium comprising cadmium hydroxide, ammonium sulfate, an alkali metal hydroxide and an alkali metal cyanide. y

7. A composition of matter adapted for use for the preparation of a cadmium plating bath consisting of a dry mixture com prising a cadmium compound and a material which tends to preventthe co-plating of zinc.

8. A composition of matter adapted for use for the preparation of a cadmium plating bath consisting of a dry mixture comprising a cadmium compound and an ammonium salt. I i

9. A composition of matter adapted for use for the preparation of a cadmium plating bath consisting of a dry mixture comprising cadmium hydroxide and ammonium sulfate.

10. A composition of matter adapted for .nse for the preparation-of a cadmium plating bath consisting of a dry mixture comprising a cadmmm compound, a material which tends to prevent the co-plating of zinc,

and a material which tends to improve the quality of cadmium platings.

11. A composition of matter adapted for use for the preparation of a cadmium plating bath consisting of a dry mixture comprising a cadmium compound, an ammoni-