US786221A

US786221A - Process of electrodepositing metals.

Info

Publication number: US786221A
Application number: US17888303A
Authority: US
Inventors: Edward D Kendall
Original assignee: EDWARD N DICKERSON
Current assignee: EDWARD N DICKERSON
Priority date: 1903-10-28
Filing date: 1903-10-28
Publication date: 1905-03-28
Anticipated expiration: 1922-03-28

Description

PATENTED MAR. 28, 1905 E. 1). KENDALL. PROCESS OF ELEOTRODEPOSITING METALS.

' Xwmmmw.

UNITED STATES Patented March 28, 1905.

PATENT OFFICE.

EDWARD D. KENDALL, OF BROOKLYN, NEXV YORK, ASSIGNOR OF ONE- THIRD TO EDXVARD N. DIOKERSON, OF STOVALL, NORTH CAROLINA.

PROCESS OF ELECTRODEPOSITING METALS.

SPECIFICATION forming part of Letters Patent No. 786,221, dated March 28, 1905.

Application filed October 28, 1903- Serial No. 178,883.

To (all whom, it may concern:

Be it known that I, EDWARD D. KENDALL, a citizen of the United States, residing in the borough of Brooklyn, in the city and State of New York, have invented a certain new and useful Improvement in Processes of Electrolytic Deposition of Metals, of which the following is a specification.

My invention relates to methods of deposit- IO ing zinc on metallic and other electricallyconductive surfaces, especially on surfaces of iron or steel to protect the same from rust or corrosion, and particularly relates to electrolytic methods technically termed cold gal- 5 vanizing in contradistinction to ordinary so-called galvanizing by the use of molten zinc; and my process has for its object to use and efiect the deposition of Zinc in required form from chemical solution which is incapable of spontaneous corrosive or chemical action on surfaces of iron or steel and from which a regulated direct electric current of low electromotive force will deposit on cathodes of iron or steel or other metal or on 2 5 other electrically-conductive surfaces a firm and adhering coating of pure zinc.

My invention consists in using with an electric current derived from a voltaic battery, or an electric generator of any suitable character and with suitable electrodes an electrolyte containing zinc sulfoglycerate, which body I prepare, preferably, by'first acting on anhydrous or nearly anhydrous glycerol with strong sulfuric acid, without or with the application of heat, to form sulfoglyceric acid, afterward diluting this product with a limited quantity of water, and then saturating this diluted acid with Zinc, preferably by agitating the same with an excess of zinc oXid, or, better, with zinc hydroxid, finally adding more water to form a comparatively dilute solution of zinc sulfoglycerate, the essential constituent of the electrolyte to be used in my process. If a somewhat-concentrated solution of this zinc sulfoglycerate be used as electrolyte, the liquid has a high degree of electric conductivity, and an electric current of even less than one volt of electromotive force when a zinc anode is used will suflice for the rapid deposition of Zinc, while a cur- 5 rent of considerably higher voltage, not ordinarily considered excessive, with suflicient amperage, deposits the zinc too rapidly; but when a more diluted solution of the zincsulfoglycerate is used an electric current of increased electromotive force-say two or three voltsis preferable, unless the electric resistance of the very dilute solution be diminished by addition of any suitable saltfor example, common sodium sulfate. From such a dilute solution of Zinc sulfoglycerate, under influence of a properly-adjusted electric current and with a suitable anode or anodes of zinc, the pure zinc deposited on polished cathode-surfaces has remarkable smoothness 5 and uniformity. Of course anodes of zinc are to be preferred for use in the herein-described process; but anodes of graphite may be substituted if required for any purpose, with the disadvantage, however, that zinc is removed from the electrolyte without replacement.

Electrolysis is facilitated by heating the herein-described electrolyte; but when used cold-21 e. at ordinary temperaturesthe rate 7 5 of deposition and the character of the deposited zinc are satisfactory and the operation requires less supervision.

When a voltaic battery or a dynamo-electric generator is not available, an object may be covered with electrolytically deposited zinc without departing from my invention by submerging the said object in an aqueous solution containing the zinc sulfoglycerate in a vessel within which has been placed a porous 5 cell containing any suitable eXcitant for an electropositive element therein immersed and consisting of zinc or other suitable metal electrically connected with the said object.

A simple form of plant with which my proc- 9 ess may be conducted is shown in the accompanying drawing, which is aview in perspective of an electrolytic tank containing the galvaniziiig solution with necessary appurtenances. A is the said tank; B B, metallic rods electrically connected with the source of an electric current, on which the anodes are suspended in the electrolyte; O, a metallic rod having suitable electric connection, on which the articles to be galvanized are suspended, the same acting as cathodes; D, the source of an electric current.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The herein-described process of electrolytically depositing metallic zinc, which consists in the electrolysis of an aqueous solution containing zinc-sulfoglycerate by means of a suitable body acting as the cathode opposed to a suitable anode, both electrodes being electrically connected with the source of an electric current, substantially as described.

2. The herein-described process of electrolytically depositing metallic zinc in the form of a hard adherent coating or plating on sur-