US526114A - Emile placet and joseph bonnet - Google Patents

Description

, invention.- By our processes, as hereinafter these processes we use salts and oompou ads invented new and usefulImproveme'nts in the plicable to metals which are very (liflicult to obtain by electrolytic action, such for examchromium'which, so far as'we are aware, has

miumcf great purity, in coherent masses of suflic ent size foryarious industrial uses,and

UNITED: STATES PATENT OFFICE.

EMILE PLAGET AND JOSEPH BONNET, OF PARIS, FRANCE.

PROCESS OF ELECTRODEPOSITION'OF C'HR OMIUM.

SPECIFICATION forming part of Letters PatentNo. 526.114, dated September 18, 1894.

Application filed August 20,1892. Serial No. 443,640. N p

091161150 Patented in France November 12, 1890, No. 209,469,

and July 17, 1891, bios. 214,940,214341, 214,942, and 214,943; in Belgium November 18,, 1890, No. 92,775 in England November 27, 1890, No. 19,344, and December 81, 1891., No. 22,856; in Sweden November 29, 1990, No. 4,267: in, Norway December 4, 1890, No. 2,283; in Germany December 5, 1890, No. 66,099i in Spain March 3, 1891,110. 11.587. and in' Austria-Hungary March 24, 1891, No. 53,381 and No- 8,074.

To all whom it may concern.-

Be it known-that we, EMILE PLACET and JOSEPH BONNET, citizens of the Republic of France, and residents of Paris, France, have Electrolysis of- Chromium, of which the following specification is a full, clear, and exact description.

The said improvements havebeen, wholly or in part, patented to us in the followingn'a'med countries: France, dated November 12, 1890, No. 209,459, and-July 17,-1891, Nos. 214,940, 214,941, 214,942, and 214,943; Belgium, ,dated November 18, 1890, No. 92,775; England, dated November .27, '1890, No.

Germany,dated December 5, 1890,.No. 66,099 5 53,381 and No. 8,074; Spain, dated March 3, 1891, No. 11,537; Sweden, dated November 29, 1890,No. 4,257, and Norway, dated December 4,1890, No. 2,283.

In aformer applicatiom'filed December 10, 1890, Serial No. 374,184, we have described a general electrolytic process particularly appleas iron and chromium. The present invention, whileapplicable to other metals, relatesmore particularly to the electrolysisof' not been obtained in this manner prior to our set forth, we obtain elec'tro-depo'sit'ed chroof' dilferent colors, as may be desired. In

ot'chromium which, heretofore have never been used or proposed fior'use tor. the pur-' pose in view,"and from which, in the manner hereinafter pointed out, metallic chromiumis produced in sufficient quantity, and with sufficient economy to constitute an industrial. process, very difierent from theresult of laboratory experiments by which the production of minute specimens of metallic chromiu m has been heretofore attempted. 1

In'the following detailed description we. have given the salts or compounds from which metallic chromium can be obtained commercially, specifying the proportions and compositions of the baths, and indicating the variations desirable with different compounds. The most important of these compounds is chromic acid, either the commercial acid,-or

chromic acid obtained from chromate or biohromate of an alkali metal. The method of using chromic acid isdescribed under paragraph first, below.

' In-paragraphs second to eleventh, we have described the employment of a series of chromic compounds, as sulphate of chromium, chrome-alum, orother salt of the sesqui-oxide of chromium,azotate of chromium, and other compounds which are equivalents for the purposes of the invention, and in connection with all of which we employ an alkaline sulphate or alkaline earth-metal to increase the deposition. Finally under paragraphs thirteenth and fourteenth .we describe the procedure when heat'is employed.

We willnow describe in detail the principal baths; which we have actuallyused. and from which the results referred to have been obtained.

First. A solution of chromicacid in water. This solutionmay be very little concentrated. One to two grams of. chromic acid in one hun dred grams of water-are sulficient. However, the more the solution is concentrated, the more abundant is the deposition.' We vary the shade'of the metal deposited by addingtp U the solution a small quantity (for example-- live to ten grams per liter) of one of the 01 lowing acids: The. phosphoric, sulphurous, 0x alic, benzoic, formic, gallic, pyrogallic, picric,-

phenic,-salicylic, and other 'analogousacids,

give very whitefdepositions of chromium. 1 I

The acetic, hydrQ-fluosili'cic, &c., acids-give brilliant deposits, but d'eeper. Boric acidgives dim grayish depositions, but very abundant. Einally sulphuric, azotic, chlorhydric, arsenious,-tartaric-, citric, lactic, tannic, &c.;

acids give depositions ofa, more or less deepshade, according to the quantity employed.

. 65 an alkaline snlpha'te or-alkaline eartbmetal,

To prepare our solution of chromic'alcid, we make use of-chromicacid obtained by the ord1i 1ary processes, or else, we produce chromic -3Cid 1fl the bath itself, in proportion as the dep- 5 oslt-ion of chrominm'is 'made. In this case we employ as a bath, a solution of'an alkal ne bichromate, and we pour into this solu- Men, in small successive quantities, an acid (sulphuric acid, nitric acid, hydroflug-silicic, or any other acid) whichin combining'with the alkaline base, sets the chromic acid free, or else, we prepare the chromic acid by putting an suspension oxide of chromium hydrated in i a soiutionof oxalic acid, or ofi 'anyiotherorganlc acid, andpassing through it'a cur'rentof electricity. ,At the end of a very'short'It-ime,-

. under theiniluence of the electricity, the oxide of chrominm is foundtransformed into chromic ac1d, acco'rding'to the -forn1'ula,2(()r 0 2c 60 =;4(C r O The best results,,how.ever, are

obtained bynsing chromic acid produced by ,means of electricity in the {allowing-way: We. prepare, first; a solution of chromate or bichroniate of anlalkalimetal and insert'-- therein a porous yessei-containingthesame solution, or simply pure water, and contain- Jug-1 also an electrode of carbon, platinum, or other conductor whichwili, not be attacked. In the external-solutionis placed aiiotliersuih 3o able' .electrode with which, is connected ther- -.pos1tiv e pole Of'fll electric genegator. After.

the electric-genri'nt passedIor sometime all of the alkaliwiil'haye passed into the poious vase, 'leaying chromic acid in solution-Lin 5 the vesselgcontaining.the-positwe electrodr d-nieeh mjicracidis absolutely, pine, and

su table not ohlyfon-the-fnrtheroperation of! -obt'ai ningchromium, but for various indgset ,tr1 'a1 uses. We obtain directly by electrolysis 4o mixtures or alloysof chromiumandoiidi iei ent metals, by dissolvinig, inour baths oi." chrom c acid, oxides or carbonates-which do not decompose the fchromicacid; such as the oxides or the carbonates of ccppen ofiron, of alnmmlum, of magnesium, of tnngsten, 10f molybdennmfof; nickeh-ofjsiilfver, 65c YWe also obtain electrolytic-deposits o'ficlirominm by employingtlie following baths: ,fSecond. A solution of ten, fifteen ort-wenty v gramsof sulphate of chromium in c'ne'hnn- 3 I dred grams of' yvater. We addto this seinlion sulphuric acid until no more oxidefof hr mium is deposited at the negative; poles When the deposit of oxide ceases it will: be known that the'bath is snflici'entlyzacidu Third. Instead ofsnlphate of chromium-we employ by preference, chrome alninxd'oubie sulphate'ofch'romiu m-and of potash, of soda 6o or of ammonia); hecausfefthe chrome-alumis more easytopreparer Weiacidnlate it'li kewise by means of sulphuric acid. To main. tate the %deposi tion,1;ve find it advantageous to add to our baths,'t en to fifteeri'per cent. of

or of afmixtnre of them.

late our baths, we may also employ azomc, phosphoric, chlorh'yd'ric, hydroflnosilicic acids; and the organic acids, or a mixture of these acids. It is thus'we have composed the following bath: tento fifteen grams chrome alum; ten to fifteen grams sulphate of pot--,

ash of soda or of ammonia; five grams oxalic. -aci or other organic acid; and one hundred 7 5 grams of water. We heat-this solution, which is green, until it becomes violet; and we obtain a bath which gives, magnificent deposi- "tions ofehromium.

Fitth. .We dispense with acidniating our 8o baths, by employing for their :i'oundation; salts very acid" by themselves, .sucli'as'the bisuiphate's, the bihospiiates, the iii-acetates, d e; The acid vi ich is found: combined in these salts in definite; proportions, acts (for the end we propose) in muc better condie1 'tions than whenwe add the id' directly to the bath} We name for gamm mmen to; twenty grams ot'chrom'e-alnm, 'fiyeto' te'n grams of neutral-or alkaline snlpha-te,'fi1ire to" p A tengramsof alkaline bi-sulphate, and one 4 hundred grams of Water. "T l Sixth, To a solution'ofl chrouiic' mayor chromate or bi-chromate of an alkali mf etaip we adda small quantity of any acid(s'ni' hur'ic '95 acid, chlonhydri'c,"phosphoricfot other." e add,;further, a sulphate, a chloride-Cor other alkaline salt; and we obtain a batlkwhioh-is' very' easily redncibleby electricity. We-takeg l for ex'am'ple-teh to fifteen grams of 11-;81kfl'1 VIC-C iliue"bi-chroinate, five to com grain s qf-:any-- slit-table acid, fifteen; to tw nt grains of chime-slan ed one hundred gramsof 'wafl f s imes? i t e aiehoi or", I fany other-reducin bodpm rg u m g jtion. more rapid. 2 v

Seventh: In a solution of chrome-alum, or any other salt of 'sesquioxide'fofl; ch rp'mium,

iwepour a soiutjio'irbf an alkaline-.bbcarben- I v ate and obtain a violet precipitate; In plnngno-1' "ing'into theliquoxgwhich holds in 'suspen-- sion this violet precipitate, the t'woelectrodes "of a batteuy sye obtain depositiondf ch'rominm attheTnegative pole,

Eighth. we may add to surf-baths Dom: i5,

.tion OLsodd-Or 'of potash get cyanide's or of alkaline'snlpho-cyanides, holdingiin solution gor. in suspension oxide ofichromin'm drjcyanide of chromium.

Ninth. :Inineaiq r 11ibin-nmilfi[fine can; :m "above, we sometimes flnddtndvantageous to employ-thesalts of chrqmidi sing aisn'it' :TefithfTh roeeo-chro nie salts Qor will mama-techs an, exa ple; an the" most:-

simple-bf thesebath's; Wetak ehydrate' ot; sesqniokideofivioietchrome, and we'dis'solve otheramlnoniacai salt.) Under the influence 1 Foprfll; Insteadof sulphuric acidto tent;

Cf electricity this, bath gives at the'neg-a tiy e pole a magnificent deposit of chromium. In-

adding to this bath an acid (chlorhydrie acid, or sulphuric acid, azotic, &c,) a series of chrome underthe influence of an electric current. p a t Eleventh. Instead of alkaline sulphatesas we have indicated above-as an example, to facilitate the deposition of chromium-we employ likewisethe alkaline nitrates, phosphates, pyrophosphates, fluorides, fiuosilicates, borates, chlorides, chlorates, sulphurets, benzoates. oxalates, tartrates, citrates,

. ally be mixed with each other, and the recovacetates, sulphites, bi-sulphites, & c., or alkaline earths. For example:fi'fteen to twenty grams of chrome-alum or of-fluosilicate of chromium, ten to fifteen grams of fluosilicate of potash of'soda or of ammonia, five to ten grams of hydrofluosilicic acid. or any other suitable acid,and one hundred grams of water. We maintain the composition constant in our baths, either by means of a soluble anode, or by theaddition of oxide of chromium, or of salts similar to those which compose these baths, or by means of a methodic circulation of solutions more or less concentrated. The baths that we havejustindicated may gener cry of the substances which compose them may vary within very great limits, according to the quality of the metal it is desired to obtain. Small quantities of alcohol, of gelatine, of sugar, of glycerine, or of other analo-' gous matters, added to these baths produce a favorable action on the quality of the metal deposited. These and analogous organic substances improve the quality of the deposited metal, as shown by actual results. This action may be due to a better grouping of the molecules, which is in some way favored by the presence of the above named substances. The explanation of the action is obscure,but the effect certain.

Twelfth. We obtain, directly by electrolysis, alloys of chromium of various metals; aluminium, magnesium, nickel, cobalt, tin, zinc, antimony, silver, palladium, platina, &c., by mixing with our baths salts or oxides of the metals we wish to alloy.- The baths being the one acid, the others alkaline, we can exactly choose the mixture of saltsor of oxides which suit the best for the deposition of the alloys that we wish to obtain. We obtain likewise alloys'in employing, in our baths of chromium, soluble anodes, as ferro-chrome,

nickel, iron, aluminium, zinc, copper, silver,

820. By taking baths of copper, of zinc, of iron, 'of aluminium, nickel, lead, tin, silver, gold,'&c., and in adding a certain quantity of one of the baths of chromium, that we have just indicated, we obtain deposits of copper, of zinc, of iron, aluminium, nickel, &c., which are" found to be considerably improved by the presence of a certain quantity of chromium which is deposited at the same time as the principal metal. Finallywe obtain alloys by chromium is 'depositing alternately superposedlayers of chrome andof the metal that we wish to alloy, and melting the whole.

baths is obtained which give depositions of Thirteenth. We work generally at the ordi nary temperature. However, we find t often advantageous to beat our baths; which gives 'us more rapid and more abundant depositions. In certain cases, even,we heat our baths to aqueous fusion and the igneous fusion of the salts that we employ. This is in effect how we work in certain cases. We take for exampleten to fifteen grams of bi-sul phate of potash, one hundred grams of chromealum, and one hundred grams of water. We heat it tothe dissolution of the salts; and we pass through it the electric current. The

negative pole. We maintain the baths by means of chrome-alum alone, or by means of a concentrated solution of chrome-alum and ofalkaline bisulphate. The bath is thus constantly renewed, and can consequently last' indefinitely. One can, mpreover, suppress water in the formation of the bath, and prepare the bath by heating, immediately, the mixture of the salts to their fusion. .Weadd sometimes to these fused bathsa suitable salt of an alkaline earth metal.

Fourteenthfllhe fusion of chromium demands a very high temperature, and we therefore employ, generally the electric current to eflfect thisfusion. Often to efiect this fusion instead of using electrodes of pure carbon, we employ electrodes composed of carbon, oxide of chromium, of chrome-salts, or of flour of chrome, the whole previously agglomerated with a solventv (borax, phosphate lime, fluoride, the.) and a reducer (zinc, magnesium, aluminium, &c.)-so that we effect at the same time the reduction and the fusion of the metal.

We may put into the composition of these electrodes foreign metals, copper, aluminium, zinc, nickel, silver, &c., or oxides of these metals in order to obtain immediately the alloys of chrome and of these other metals. Finally, we find it advantageous to introduce in the crucible where we effect this fusion, inert gases or reducing gases, such as hydrogen, carbureted gases, gases containing the dust of zinc, of aluminium, &c.; and we introduce these gases by the help of a tuyere, or simply by the .interior itself of the'electrodes which in this case are hollow.

We would observe in" conclusion that, as we are well aware, Bunsen in 1854 experimented with. protoohloride of chromium to obtain by electrolysis infinitesimal particles of metallicv chromium. The protochloride of chromium (OrCl) is an extremely rare and expensive compound costing now about one hundred. and fifty dollars per kilo, and moreover very deposited immediately at the I too unstable, decomposing instantly upon exposble e 8e. Theiprotoehloride has and could not beusedsaye for'alaboratory experiment, and isessentially difierent 1n ehar'scter and in results i'mm eliromic. acidor the-equivalents thereof employed m our p I It has also been proposed to separate metals (chromium among others) from each other by transforming the metals into double oxalates and usingeolua tions of these in electrolytic baths. This method of analysis isof no value for and can- ..not be adapted tofche extraction of chromium f posited at the negatii'e electrode is o veryr impure and commercially worth less, being very differentfrom the pure-chic, A mini obtained by our process;

: of organic acids,

by electrolysis, because first, the metal debadqualit-y,

and second, as well as all compounds are too costly who used oommercrally: 'We disclaim compounds formed r becanse'the oxaiates;

with organic acids. It has also beenfpro':

iumoh the surface-of posed to deposit chrom metallic objects fliom a'bath of chromium dissolved in-a. doublechloride of sod-a and am in. this mannerand to plate othermetals m'enisi It is impossible to-dissolve chromium .theremth. Though this method was proposedin-1852, it iswell kneiyn: that'no arti eles electroplated rith-ehromium were ever will? 1 P 9 'ried into practice.

1; The process herein described of produc= need until our present invention ,vlvas cer- 3'0 Wecleim as our invedxtiun'or discoverying electrolytip'deposits of metallic chromium,

by. passinr'an electric, current throu electrolytic. 'bath essentially 01a soluble chromi'c compound, such as chromic acid, in aqueous solution as set forth.

'2. The process herein described of producing metallic chromium, by passi ng an electric current through a. bath containing'a chnomiccompound, as specified, in aqueous solution, i

and a salt of an alkali fr alkali earth metal. 3. The described'process of obtaining elec' trolytic deposits of, chromium by forming a bath of a salt of compound of chromium,

'such as hereinbefore specified, and -a salt'o'l."

amalkali eartbmetal, heating the bath, an" I passing 1m electric current through the mm .4,

substantially-as described.

Rom. M, Rodin;

Joshrrr loim'xmm 5e Intestimeny whereof We have signed'this