US1709268A - Electrodeposition of metals - Google Patents

Description

' Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

nu:oraonnrosrrron or mums.

No Drawing.

In the electro-deposition of metals in the form of tubes or sheets, it is usual practice to provide upon the mandrel or former and as the base upon which the deposited metal can grow, a covering or coating of a material or mixture of materials which, whilst'havin the necessary properties for ensuring a goo birth or initiation of deposit, can be readily detached from the latter when deposition is completed by melting so as to allow of, the

convenient withdrawal or removal of the deposited tube or sheet from the mandrel or former. A usual procedure is to depositlead or a suitable wax impregnated with graphite or other electrical conducting material upon the mandrel or former and to electrolytically deposit the tubes or sheets upon the lead or graphite-impregnated wax. On the comple tion of the electro-deposition of the tube or sheet, each mandrel is placed in a furnace or otherwise suitably heated to melt the depositin surface of lead or impregnated wax, when t e tube or sheet can be withdrawn or removed from the mandrel or former.

It will be readily understood that the employment of a special depositing surface is a source of expense and such surface is a freuent cause of failure in the electro-depos'it1on. Attempts have been made to provide a metal or alloy from which the mandrel or former can be constructed which will serve for the direct deposition of the metal without the intermediate coating, but as far as I am aware, a commercially successful result has not so far been attained in this direction. It will be appreciated that the metal or alloy used must provide a surface upon which a good birth of-deposit can be made, must be insoluble or practically insoluble in the electrolyte and must not have such a degree of attachment to the deposited metal that the latter cannot be removed therefrom by a blow or pressure. y research and experiment, I have found that a mandrel or former made of an alloy of steel and chromium and/or iron and chromium, after having its surface polished is capable of successful use for the reception of electrolytic deposits of iron and other metals. The percentage of chromium in the alloy can be varied without seriously affecting the properties required of a mandrel or former, and as hereinbefore indicated, but

Application filed June 80, 1925, Serial No. 40,895, and in Great Britain July 24, 1924.

I find an alloy containing iron and/or steel with from 12 to 14 per cent chromium gives good results.

I have further found that if for a tubular deposit the mandrel has a slight taper, than after depositing the metal thereon, a subsequent annealing and chilling process results iin tire detachment of the metal from the man- My invention comprises therefore the im- I proved mandrels, formers or bases for use in the electro-deposition of metals made from an alloy of steel and/or iron and chromium, and having a polished surface.

My invention further comprises the employment in the electro-deposition of oylinders or sleeves of metals, of a tapered mandrel or former made from an alloy of steel and/ or iron and chromium.

My invention further com rises the improved process of and means or facilitating the obtaining of metal cylinders or sleeves deposited on mandrels, consisting in depositing the metal on a preferably tapered mandrel made from an alloy of steel and/or iron and chromium, heating the metal and mandrel and then quickly cooling or chilling the metal and mandrel whereby separation of the two is effected.

In one convenient application of the invention to the deposition of metal cylinders or sleeves, the chromium alloy mandrel is made with a small taper and is given a polished surface. The metal is then deposited thereon. The mandrel with the metal thereon is then placed in an annealing furnace and after the requisite temperature for annealing purposes has been reached and maintained for any desired period, the mandrel and metal are lowered into a vat with a cooling fluid therein. The effect of the chilling gctilon is to release the metal from the man- My improved mandrels or formers gives a good birth of deposit, allow of the ready detachment or removal of the deposited metal tube or sheet therefrom either before or after the annealing process, and are practically insoluble in the electrolyte.

It will be understood that ,my invention can be applied to formers of disc, ribbon or sheet form which are then made of an alloy of steel and for iron or chromium, the face of which has been polished. The depositedtubular polished tapered cathode made of an alloy containing a major proportion of iron and a, minorproportion of chromlum, heating the cathode. and deposited metal, then quickly chilling the. metal and cathode Whereby separation of the formed tube and cathode occurs.

y 2. A process for the electrolytic formation of iron tubes which comprises electrolytically depositing iron on a tubular polished tapered cathode made of an alloy containing a major proportion of iron and a minor proportion of chromium, heatin the cathode and deposited iron, then quick ly cooling the iron and cathode whereby separation of the formed tube and cathode occurs.

8. A process for the electro-deposition of metals which comprises electrolytically depositing a metal upon a polished cathode made of an alloy containing a major proportion of iron and a minor proportion of chromium, heating the cathode and deposited metal, then quickly chilling the metal and cathode whereby separation of the deposited metal and cathode occurs.

In testimony whereof I have signed my name to this specification.

-.- moms WILLIAM smmaa nurcums.