US 630246 A
Description (OCR text may contain errors)
UNITED PATENT OFFICE;
FRANK s. LoEB, or NEW, KENsINGToN, rENNsYLvA IA.'
PREPARATION OIFYALUMINIUM FOR ELlEci'I oP'LA'nNc.
SPECIFICATION ramiig sa'orneaers Patent No; 030,246, datedAugusir 1 1899. pp at qd September 8,1898. Serial lie-690.210. (a al a To all whom it may concern:
. Be it known that I,FRANK S. LOEB, of New Kensington, in the county of Allegheny and State of Pennsylvania, have iiivented a new and useful Improvement in the Preparation of Aluminium forElectroplating, of which the following is a specification.
The object of my invention is to electroplate aluminium with other metals, an object which, although often" tried, has not hitherto been accomplished satisfactorily.
To prepare the aluminium to receive the electrodeposit, I treat it with one of the acids of the halogen group, preferably hydrofluoric acid, which I have discovered to be much the best and to which I intend to vmake specific claims in addition to the broader claims. Then I quick the aluminium with a mercury solution, preferablyrassolution composed. of nitrate of mercury, to whichis added-a cyanid. Then after the quicking I treat thealuminium again in the acid-bath, after which it is ready to receive the electrodeposit. By thus treating the aluminium with acid after it has been quicked the plating of metal subsequently deposited thereon is rendered very adherent and durable, much more so than would'be the case if the guicked aluminium were put in the plating-bath without such retreatment with acid.
-I shall now describe the preferable compositions and preferable proportions which I have used in this preparatory'treatment and in electroplating, promising that within the scope of my claims the same may be variedby the skilled electrometallurgist in many way.
The hydrofluoric acid is preferably dilute, made by adding, say, twenty-fi ve cubic centimeters strong acid to two thousand cubic centimeters water. The aluminium, having first been cleansed to remove grease, dirt, 8m.
and preferably rinsed in .hot water, is immersed in the hydrofluoric acid until were gen gas is freely evolved from it.
Thequicking solution into which the aluminiumis put after treatment in theh'ydrofiuoric acid is preferably composed of fifty '6. grams mercury dissolved in, say, onefhun-j; d-redcubic centimeters strong nitric acid, this being added to two thousand cubic centimefters water and thirty grams potassium cya'nid. The time of immersion of the alumini um in the quicking bath shoulddepend upon the strength of the bath. With a bath comsuflice. Otherquickingsolutionsof mercury may be used. 1
The hydrofluoric-acid aluminium is introduced after its removal from the quicking-bath may be constitutedin the same manner as the acid-bath above gas.
' aluminium is put after its second acid treatment is an alkaline or neutral solution, which when copper is to. be deposited is preferably constituted as follows, and used hot-say at a thick paste with water and add eight ounces sodium carbonate dissolved in two quarts of water. In a separate vessel I dissolve eight ounces sodium bisulfite in two quarts water and add this sodium-bisulfite solution to the I also dissolve six ounces potassium cyanid in three quarts water and add it to the previous mixture, and then add five quarts water, making it up to three gallons, when the bath is ready for use. When used, I connect a copper the negative wire objects to be plated. When in'a suitable manner-say by'rinsing in run sawdust. polished, or bufied without injuring the de- For electrodepositingbrassbn aluminium an "alkaline brass, both of composition analogous v2 ,to thos'e'above described,m ay be used. A good b'rassfplating bath is made of five ounces cop-r grac'etate and'fiv-e ounces zinc chlorid fused,
ved inwater. To this are added ten dinm bisulfite, th'e'ni'sev'en ounces potassium cyauid and waterenough to make up, say,
three gallons. 'i p a pounded as just stated about five seconds will anode to the positive wire and suspend from 5 sufliciently plated, the article may be cleaned bath into which the described,and the length of immersion should be sufiieient to' cause evolution of hydrogen j The electroplating solution into which the temperaturaoffnomliifl, v1191.180. Fa renhe I make eight ounces of copper acetate to a is iv copper-acetate and sodium-carbonate solution.
ning water, then in hot water, and dried in It can then be scratch-brushed, y 0 posited film, which is strong and adherent, so
and forth repeatedly without cracking the 1 n s'sodiumcarbonate and five ounces so- I g; r V 630,246
'1 i "Io plate'with silver, the following is'a good bath: three ounces silver chlorid, eight ounces potassium cyanid, and eight ounces sodium I v carbonate dissolved in, say, one gallon water.
The foregoing plating-baths are i-llus'trm tive, and as the essence of my invention is' not the depositing of any particular metal or 'of depositing a metal from any particular alkaline; solution I deem it unnecessary further "toelaborate onthis point. v E Icla'im-.
; 1.- The methodrot preparing aluminium for electroplating, which consists intreatin'g the aluminium with hydrofluoric acid-,then quickaluminium and then treating the quicked aluminium with hydrofluoric acid; substantially as described. 1
1 In testimony whereof I'havehereunto set my hand.
r "FRANK S. LOEB,
Witnesses:- I I j GEORGE B. BL MMI G, s
' G.I.'H0 1)sH1P. f