US1947938A - Process of making a new composition of matter and the product thereof - Google Patents

Description

E. HEY 1,947,938

PROCESS OF MAKING A NEI GOIPOSITION OF MATTER AND THE PRODUCT THEREOF Filed March 23. 1929 f lNVENTOR/e/ lflfSf 6 BY 5/ ATTORNEY Patented Feb. 20, 1934 invention relates to the process of making a' 4 PROCESS OF MAKING A NEW COMPOSITION OF MATTERAND THE PRODUCT THEREOF Ernest Hey, Bellingham, Wash. Application March 23, 1929. Serial. No. 349,456 5 Claims. (01. 148-24) new composition of matter and the product thereof. More particularly, my invention relates to the comminuting and intermixing of aplurality of 5 metals through the medium of forming a coherent sponge-like mass or body derived as a reaction product of said metals in an acid medium, the forming of said sponge-like body or mass operating to reduce said metals to a comminuted form of a degree of fineness far greater than that which characterizes mechanical processes, and to impart porosity to said particles of metal, by reason of which fineness, porosity and sponge treatment said peculiarly well metals are rendered specially and adapted for melting by heat,

(either by a soldering iron or in a crucible to provide an ingot),

to form a homogeneous mass for ing metal coating compound.

In order to more clearly understand my invention, reference will be made briefly to prior art compounds. First a distinction is to be made between compounds used as cleansers commonlyknown as fluxes, by way of preparing the metal parts to be soldered on the one hand, and those compounds which function both as cleansers and as binders for said metal parts on the other hand. Compounds of the cleansing type may be obtained on the zinc soap and a market consisting of zinc chlorid, vehicle as a vaseline-rosin mixture. These operate to remove the oxide formed on the surface copper, but, be

of such metals as tin, iron and it noted, they are of no practical use on aluminum. K

Compounds of the second type, that is, cleansing-binding character, consisting of zinc chlorid, tin metal, inertmaterial and water, likewise may be obtained on the market, but serious objection obtains to them in that their melting point is relatively very high. It will beunderstood that it is compound if it got the tin in the necesary small particle form to necessary to melt the tin in the is to form a binder, in order to form an alloy with the metal to be soldered or cemented. Here, also, be it noted, such cleansing-binder compounds are of no practical use with aluminum, and

are so marked on their labels.

A further distinction is to be made between these compounds in the form of a paste on the one hand .and of a powder on the other. Mania festly, the paste form is highly desirable as it is most convenient. For example, ifthe surface is curved, itWill stick where it is placed when in the paste form, wh

ile powder compounds "fall away, is exposed to air drafts, the compound in the powder form would blow. away.

Also, all work on vertically disposed surfaces, or

under surfaces, requires the paste form of the trate the importanceof' the paste form of the 66 compound.

'I'he cleansing type of compounds described above may be obtained in the paste form, but not the cleansing-binder type. The tin in this latter type of compound is of relatively large 70 size, i. e., large granules or shot, and tin being of such great weight would readily sink down through the vehicle to the bottom of a container, and thus result in a gravity separation which would be highly objectionable. -The cleansing.- I5 binder type of compound is that regularly prepared in the powder form. But even as powders, serious objection obtains to them in that the zinc chlorid when exposed to the air takes up water, i. e., deliquesces, and becomes a liquid which lets the tin separate out, thereby resulting in' a great wastage of the material. Also, the zinc chlorid in the liquid form after separating from the tin seems to set, i. e., becomes solid.

Both types are further objectionable in that they are not characterized by the quality of spreadability, i. e., when the solder iron is dipped into them, the compound adheres in large irregular masses. By reason of this lack of spreadability, there is a failure to provide uniform penetration in the metal parts to be soldered which results in a'tinning over of small oxidized areas, and this results in a poor union, and explains why so many metals thus soldered pull apart. Not being readily spreadable such compounds form a separate layer, as it were, over the oxidized area.

A primary object of my invention is to overcome in general all the above named objections, to provide a tinning soldering compound which constitutes a cleanser and also a binder for metals, iron, tin, copper, gold, silver and platinum,

i. e., all metals, and particularly including aluminum, as well as aluminum alloys. 8

In providing a soldering paste of two metals differing in specific gravities in association with a vehicle, the degree of fineness of the metals is of the utmost importance. Heretofore, it has been attempted to provide solder pastes embodybeen satisfactory, particularly for the reason of the mechanical separation of the tin from the vehicle,-'ordinarily vaseline, or the like. Furthermore, in providing an intermixture of metals, whether it be for a mere mechanical intermixture or an alloy, it is well recognized that the degree of fineness of the metals largely determines the character of the resulting product. In providing metals for spraying purposes in plating hot surfaces, the degree of fineness is manifestly important in providing a smooth surface and uniform coating, and through the medium of the sponge-body herein described such comminution for such purpose is possible.

Tin is particularly obstinate to all mechanical methods of comminution, and thus is presented a metal affording particularly serious diificulty in this respect, which difficulty is overcome by my invention as will hereinafter appear. In attempting to provide a solder paste embodying zinc, it is true that zinc may be mechanically pulverized to a degree of fineness that it will remain fairly well dispersed through the vehicle and will not tend to separate out by gravity when allowed to stand. However, zinc thus mechanically pulverized becomes heated and upon expo- I sure to the air readily oxidizes, and likewise even when pulverized in a protecting medium. When such a paste is employed in soldering, it forms a black and smutty mass on the job to be soldered as well as on the soldering iron and the bond is highly unsatisfactory. This difiiculty with zinc is overcome in my invention.

Primary objects o fmy invention are to provide said compound in the convenient paste form which does not decompose'and which retains the metals of a porous character uniformly distributed therethrough, the metals being of such comminuted form that they are not subject to gravity separation; to provide said compound which may be used in forming a union between wires as electrical conductors Without the use of any solder and which will not deteriorate with age; to provide such a compound having the metals comminuted through the medium offorming a coherent sponge of such metals and then intermixing the sponge with a vehicle; and to provide said compound characterized by having metals which form an alloy with the metal to be soldered, said metals of the tinning compound at the same time being characterized. by having a low melting point.

For purposes of clearness and definiteness of disclosure, I primarily will describe my invention in connection with tin and zinc, but it will be understood that in place of the tin, lead may be employed, and in place of the zinc, aluminum may be employed, and also other metals set forth in the formulae and equivalents hereinafter described.

In general and briefly, it may be stated that I accomplish my invention by providing an acid solution of a metal, hereinafter referred to as the acid metal solution, and regulating the precipitation of this metal by a second metal, hereinafter referred to as the anchoring metal, so as to form a coherent sponge-like mass of said metals in an exceedingly comminuted form, said mass being permeated and filled with gas, and then washing or neutralizing the acid solution in said sponge-body and keeping said body unexposed to the atmosphere until the metals are melted, i. e., the melting may proceed forthwith while the sponge is still wet or the sponge may be kept in water for later use.

The above mentioned general objects of my invention, together with others inherent in the same, are attained by the process illustrated in the following drawing, the same being preferred exemplary forms of embodiment of my invention, throughout which drawing like reference numerals indicate like parts:

Figure 1 is a view of the anchoring metal in the preferred form of a loosely rolled sheet;

Fig. 2 represents the coherent sponge-like mass permeated and extended by gas when the sheet, as shown in Fig. 1, is exposed to a stannous chlorid solution diluted with water;

' Fig. 3 represents another form of the anchoring metal having the metal disposed in grid forms;

Fig. 4 shows a honeycomb arrangement of the anchoring metal;

Fig. 5 shows another form in which the anchoring sheet may be provided, i. e., telescoping plates;

Fig. 6 shows the anchoring sheet metal in the form of wire rolled into a ball; and

Fig. 7 shows still another form of arranging for the anchoring metal to be in extended form, namely, crimped.

This drawing illustrates the preferred way of arranging for the anchoring sheet, although the same may if suficiently thin be laid flat on the bottom of the container of the metal-acid solution, or the anchoring metal may be in a very finely divided condition if the solution strength is very much reduced.

In providing the new composition of matter embodying my invention, the following formulae may be.employed:

Formula I .--Tinzinc product A. Dissolve 1.25 pounds tin in ten pounds hydrochloric acid (commercial or C. P.), the hydrochloric acid being preferably free of sulphur. The tin may be in the form of an ingot, shavings, granulated, babbitt, pewter or any alloy containing tin, so long as the above amount of tin is present. The amount of tin is sought which will practically satisfy the acid. Therefore, an excess of tin better insures the saturating of the hydro- 12d chloric acid. To save time, in preparing this stannous chlorid solution the tin may be melted and poured into the acid. After the acid is fully satisfied, i. e., all action ceases, as evidenced by the giving off of gas, which is from eight to 125 twenty-four hours, the solution is poured off, which may leave the ingot in its original form but greatly reduced in weight. When the tin is put into the acid in the molten form there is nothing left but a small amount of sediment. Using stannic, i. e., tin chlorid, according to my experience to date, in the powder form does not give satisfactory results in the forming of a coherent sponge-like mass hereinafter to be described as does the forming of the stannous solution as above specified, but instead it gives a jelly-like mass.

B. Add to the stannous chlorid solution as above prepared one hundred (100) pounds water. If the stannous chlorid solution is allowed toset until some oxidation of the metal occurs,(this generally commences after about 144 hours, and I preferably allow it to set until after about 240 hours), then it needs only about eightly (80) pounds water. The longer it sets, the less water 145 is required.

I C. Introduce zinc sheets into the container of the above solution. These sheets are preferably in 2. rolled up form as indicated in Fig. l, which represents a sheet of zinc of about one-tenth 159 inch 6") in thicknesa-whic has been rolled up tightly upon itself and then released so, that it springs slightly apart. This is placed in the container on end. The-zinc may also be in any of the other formsindicated in the drawin the idea being that it is preferably in extended form for reasons which will hereinafter appear. The various forms are simply illustrative of the fact that the particular form is only significant insofar as it involves having the zinc in an extended a form as respectsits weight. Upon the introduction of the zinc sheets, the tin is precipitated from the solution and adheres to the zinc sheet in the form of distinct crystals and continually grows thereon somewhat similar to frost.

While the tin is thus depositing on the zinc sheet, bubbles of gas are being released through the coating whichis being formed on the zinc sheet, and as the coating increases, it being understood that said coating is developing on the inner convolutions as well as the exterior, a point is reached when the sheet is forced to' slightly unroll to accommodate the pressure developed by the accumulating coating within. This is facilitated bythe fact that the sheet of zinc is becoming thinner and offers less resistance. The coating seems to constitute a protecting enveloping metallic body distended by gas for the zinc sheet, which sheet may be considered the anchoring metaL- This protecting body is a sponge-like mass and finally reaches such proportions, as indicated in Fig. 2, that it rises to the top of the solution, part of it extending above the surface. Finally, all the zinc sheet is acted upon by the solution so that it no longer remains as a sheet, and all action ceases, so far as is evidenced by the giving off of gas.

It will be understood that the forming of this sponge-like mass, or enveloping and protecting metallic body, (enveloping and protecting relative to the zinc sheet during action), only results when especially provided .for. The action of the acid upon the zinc and the forming of the en- .veloping mass for the zinc must be provided-for.

Ordinarily, as is well known, the zinc sheet will be acted 'upon so violently and actively by an ordinary hydrochloric acid solution 'that no coherent metallic sponge-like mass will be formed on the zinc sheet. Instead, with zinc in the form of an ingot in the bottom of the container, short string-like, masses of tin attached to the zinc ingot are developed, and these grow until they are one-half inch (t 2") or' so long,- and then they break loose and rise to the top of the solution. These strings of'tin should be removed because if vtheyare allowed to remain on top of .the solution they will be gradually re -attacked by the acid and redissolved, and thezinc goes into solution as zinc chlorid simultaneously with.

the precipitating of the tin. These conditions are just the opposite of what I desire. My purpose is to so regulate the action of the acid solution upon the-zinc sheet that a coherent sponge-like gas filled mass forms upon the surface of the zinc. As the tin is precipitated upon-:the zinc sheet and gradually form'sthe coating which becomes the sponge-like massdistended by gas, the said coating operates to envelop the zinc and in itself seems to retard the action of the acid, permitting the gradual building up of the coherent mass herein referred to. The building of this coherent sponge-like mass starts with the precipitation of minute tin crystals upon the zinc and thereafter the coherent sponge-like mass, according to my observation, seems to deinch 'd') in thickness, which has been rolled up der a magnifying glass that the minute metallic tin crystals, which adhere to the outside of the sponge-like mass, are continually changing, i.e.. they seem to be dissolved by the acid and 'reprecipitated. r

'If, insteadof the zincsheet, zinc chlorid either as a solution or asa salt is employed, a jelly or clabber-like mass results after the lapse of some time, but this is so unstable that it does not lend itself to being melted down with a resulting ingot, as will hereinafter be explained with the sponge-like mass herein described. While it is preferable to have the zinc sheets in a form which will expose as large an area thereof as possible to thesolution, or in other By way of regulating the rate of forming the sponge, it may be noted that the forming of the sponge may be hastened by the addition of a relatively small quantitybf nickel chlorid solution to'the stannous chlorid solution; or the forming of the sponge may be retarded by adding a neutralizing agent, such as water, soda bicarbonate or ammonia. If the tin chlorid solution is only three-fourths or partially saturated, then the acidity must be reduced. That is, the degree of saturation governs the forming of the sponge, as well as the strength of the acid. Relative toregulating the forming of the sponge, this may be done as above indicated in'one of several ways, or by combining one or more ways. The

strength of the acid solution and the thickness of the anchoring sheet are important factorsthe strength of the acid-metal solution should be adjusted to the buoyant force of said solution upon said sponge-body so that said buoyant force is of a magnitude less than that required to detach said body from said first metal.

D. After the sponge ceases to form, which is evidenced by the cessation of the evolution of a gasin the form of bubbles rising through the solution, the sponge is removed, draining off part of the liquid, and then promptly immersing the same in water, care being taken preferably not to squeeze before so immersing. This immersing or washing, removes or neutralizes the action of the acid that may be still confined within the sponge. The term neutralization will be used herein to include eliminating the acid effect, either by washing in water only, or by employing chemicals to secure a greater degree of eliminating such effect. Ifthe sponge is allowed to remain in the acid, it is noted that it will gradually be-re-absorbed by the acid for a large proportion of its mass. i

After eliminating as much of the acid as possible by the water bath, the sponge is removed and the water squeezed out. Thus is prepared the coherentsponge like mass 9} body. This may be treated toanTalkaline solution to still further neutralizewhatever acid solution may a still remain in thesponge-body, but for making tinning solder paste this is not necessary. After washing. in water iand then squeezing out the water, the mass is immediately mixed with the vehicle, or the vehicle and whatever other compounds desired. The mixing should not be delayed, i. e., the sponge body should not be exposed to the atmosphere, or the metal particles will be oxidized. To one hundred parts of this sponge-body I preferably add two hundred parts of a vehicle which may be composed equally of Vaseline and rosin. Mineral and vegetable oils, resin gum and waxes or similar substitutes may be employed as vehicles. I also find paraffin oil and Vaseline to give excellent results as vehicles. It is preferable for metals other than aluminum to add either rosin or waxes or tallow or resin gums, or any or all combined to operate as a flux. Furthermore, alkaline salts of chlorine, such as ammonia sodium chlorid and zinc chlorid have been found to serve well as a fiux. I

A microscopic examination of the metallic particles of the sponge showed them to be pitted, that is, the surface of the particles to have depressions. This leads to the conclusion that the particles themselves are porous and have particles of gas entrapped. This may in part explain why the particles when mixed with the vehicle remain uniformly distributed therethrough, that is, their buoyancy is due to their reduced weight, both on account of the fineness of the particles, and secondly on account of the porous character of the particles. It is understood that pure tin cannot well be pulverized mechanically, finer than thirty mesh, whereas in my invention the particle size is many times smaller.

If ordinary solder, -50 tin and lead, is finely ground and put in a paste of Vaseline arid a suitable chlorid for fluxing, even when pulverized to 300 mesh, which is considered as fine as it can be made at the present time, still it will separate out by gravity, unless the vehicle is made excessively heavy and then it is not suitable as a paste, since it lacks spreadability.

E. Having eliminated the acid solution by means of the water bath, the said sponge product may be placed in a crucible while wet and forthwith melted. This is done preferably in a closed container. ingot of metal or a metallic product characterized by fineness of structure and by having greatly increased alloying and absorbing properties as respects other metals. Thus, this product in turn serves as the basis for forming many other products, and will be referred to as the basic tin-zinc product, the tin-zinc indicating that it is the'reaction product of, or derived from, the tin acid solution and zinc anchoring or precipitating sheet. It forms a solder of greatly improved properties over the present solder. This product has the remarkable property of resisting 'corrosion,-even when exposed to hydrochloric acid fumes for weeks, it still retains its bright metallic tin-like lustre.

If the melting is not to be done for some time after squeezing out the water, the sponge should be kept free from the air and this may be done by immersing the same in water. If the sponge upon being removed from the acid solution is not squeezed and is not washed with waterand is exposed to the atmosphere to\ dry, it will collapse into a fine black dust. If this dust is heated, a yellow powder results.

The weight of the ingot resulting from melting the sponge is greater than the weight alone of either the tin employed or the zinc employed, and by the addition of certain other compounds,

Thereupon the sponge becomes an as herein explained, it will be noted that the weight of the ingot may be caused to approximately equal that of the original tin ingot dissolved plus the weight of the zinc sheet.

Formula II-NiclceZ-tin-zz'nc product A. Make the tin chloride solution as for the basic tin-zinc product.

B. To every gallon, i. e., 11.25 pounds stannous chlorid, add 25 cc. nickel chlorid. The balance of the process is similar to that set forth for forming the basic. tin-zinc product. By adding the nickel chlorid solution, the recovery of the zinc is increased with the addition of such nickel chlorid up to about 25 cc. per gallon of solution. If more is added, the action upon the zinc becomes too violent and no increase in recovery of the zinc results, but rather a less recovery is noted. Diluting with water in this instance, it has been discovered, does not reduce therapidity of the action. Hence, by the addition of the nickel chlorid the weight of the ingot resulting from melting the sponge is substantially equal to that of the weight of the tin dissolved in forming the saturated hydrochloric acid solution and the weight of zinc by which the zinc sheet is reduced. Thus, the weight of the ingot is practically equal to the amount of tin and zinc originally employed. The conclusion seems warranted that through the medium of the sponge the composition of matter or product is provided, characterized by its degree of fineness of structure and by its homogeneity, and is a reaction product of both or all of the metals originally employed. The a ingot resulting from Formula II, in which nickel is employed, has a distinctly increased lustre over the basic ftin-zinc product. Upon melting the sponge, wherever the nickel is present, I find it necessary to use a closed container, with a small vent in the top, so that no fiame can enter the crucible. Otherwise, the readily.

Formula IIICop'per-tin-zinc .prpduct sponge will burn A. Make the tin chlorid solution as in Formula I.

B. Add one hundred pounds water.

C. Add copper chlorid solution. The amount of the copper employed depends on the use to which the final product is to be put. strengthens the resulting metallic composition and raises its melting point. If the product is to be used for a solder or for brazing purposes, the copper should not be added to an extent greater than one-half of one percent of the tin present.

D. The zinc sheet is introduced as hereinbefore explained, and the sponge begins to form. How-. ever, the copper goes to the bottom asa fiuffy The copper t or heavy jelly-like mass, distended with gas, but

but

H. The sponge is melted in the crucible, using much more heat than in the case of Formula I. It seems that the sponge will melt first and then next the fluff and the latter seems to be absorbed into the melted sponge. Whenever nickel is present, a closed crucible must be used having a small .60 to saturation point.

memes Formula IV Lead-zinc product 6 A. Instead of using tin to provide the original metal-acid solution, lead may be substituted.

1.25 pounds lead are dissolved in ten pounds aqua regia consisting of four parts of hydrochloric acid and one part nitrieacid. Using the aqua regia 1 in this proportion hastens the action of dissolving the lead and holds the same in solution. The aqua regia should be warmed and maintained so during the treatment of the lead.

B. One hundred pounds water are added to 1 this lead solution.

C. The zinc sheets are introduced as in Formula Land the balance ofthe process for this FormulaIV is similar to that for Formula I. A sponge results as in the previous instance which may be melted down. The ingot does not have a lead color but rather a dull tin color, which does not turn dark, i. e., corrode, upon exposure to the atmosphere asdoeslead. Ordinary lead becomes dark, i. e., after exposure the characteristic dark color of lead results.

Kit is desired, straight hydrochloric acid (com- -mercial strength) may be used instead of aqua regia, heating the acid and keeping it hot until the lead is dissolved. Uponcooling the main bull;

so of the lead is precipitated as a white powder. Also,.if a weaker solution of aqua regia is used than that indicated, there is a marked tendency for the lead to be precipitated as a white powder.

Howevenwhen the zinc sheet is added it is to be 85 noted that this white powder. disposed in the be tom-o1 the container is picked up and forms the coherent sponge-like mass or protective body substantially as ii the same was actually in solution.

Formula V-Copper-lead-zinc product A. The lead solution is prepared as in Formula IV and the balance of the process is similar to Formula III. Instead of making up the copper, chlorid solution separately, copper may be placed in the acid along with the lead, and the solutions formed simultaneously. This has the advantage of producing a product characterized by-having a much lower melting point. In this instance,

. no coherent sponge-like mass is formed. All goes to the bottom as fluff; When the copper and lead are dissolved simultaneously, there is none or the lead-white powder formed in the bottom. Without the copper and even with aqua regia there is a small amount of the lead that falls as a white "powder.

Form ula VI-Silver-lead-zinc product A. Lead is dissolved as in Formula IV. B. An aqua regia solution of silver is made up After the one hundred pounds of water are added, then the silver solution is added, and'the balance of the procedure is that set forth for Formula IV.

' The sponge thus provided requires in melting to form the molten ingot a relatively high heat, substantially equivalent to that in the case of copper,

tin and zinc. This produces an ingot almost as bright in color as silver and does not tarnish on exposure to the; atmosphere. In the case of the silvera true sponge is formed. Copper in every instance drops to the bottom as a fluffy, jelly-like black mass, and asstated in the instance of tin it pulls some of the tin down with it, but only a small portion oi. it. But in the case of lead, as 'stated, the copperrpulls the lead down with it s when the lead and copper are dissolved together,- I and no sponge is formed. When it is dissolved with hydrochloric acid, then the copper with the lead buildsa true sponge.

- Formula VII- Gold-lead-zinc" product A. The same procedure as in Formula VI. Formula vm Instead of using zinc as the precipitating means for the metal in the acid solution or as the sponge anchoring metal, I have discovered that alumi: num may be so used. This operates in every respect substantially the same as does the zinc. The ingot resulting has a slightly yellowish tint and seems finer-grained than in the case of 'the'ingots formed with the zinc as the spon e anchoring metal.

The composition of matter or product in the form of an ingot resulting through the reaction of tin and zinc, for example, upon each other through the medium of the sponge, has the property upon being melted of absorbing other metals and this even when such other metals may be in relatively large'proportions. By way of illustration, in providing a plating compound for iron products, it is known that thirty-five parts tin may unite with and absorb as much as sixty-five parts lead; However, ten parts of the metallic composition embodying my invention, i. e., for example, the tin-zinc? ingot as prepared in Formula I, has the power or absorbing ninety to one hundred parts of lead,'and the resulting product has the powerof resisting corrosion while the 1 3565 combination of tin-lead does not. That is, even though the latter combination has a very muchincreased quantity of tin present, it cannot impart as good a non-corrosive property to the combination as a small quantity of tin when treated according to my invention to form the reaction product of tin and zinc as set forth in Formula I.

To provide tin in extremelycommin'uted form, take the sponge, subject it to a weak solution of hydrochloric acid, (ten parts water to one part acid), for a few minutes until all the violent action is over, which indicates that the zinc has been redissolved from the sponge. Then take the balance of the sponge and immerse it in water, or

in water which is saturated with sodium bicar- 125.

bonate, until a complete neutralization of the acid is effected. Next, take the sponge so treated and put in a vacuum and subject it to warmth. After drying, subject it to a blast, which will cause a separation of the smallminute particles, or any 13- other suitable method may be employed to dis.-

. integrate the sponge into the tin particles.

The theory' which I feel best explains the action when thesponge is-formed is as follows, and is suggested by the ionic theory or electrolytic dissociation. When the metal tin is precipitated from a solution of stannous chlorid by means of the metallic zinc, the following ionic equation expresses the change.

In other words, the two unit charges of positive electricity have been discharged by the tin ion, which then ceases to be an ion, but appears as ordinary metallic tin, and 'elretransferredto the metallic zinc, which then ceases to be ordinary metallic zinc, but passes into the solution as a zinc ion.

By so regulating the reaction betwen the metalacid solution and the anchoring sheet or metal, as

acted upon, so that a metallic sponge gradually is permitted to be formed, growing from the inside.

out as hereinb'efore explained in Formula I. It will be understood that this is only submitted as a possible explanation of the complex action occurring during the gradual forming of the sponge-like mass under the conditions specified.

The reactionsinvolved in preparing the above products are as follows: The precipitating metals, magnesium, aluminum manganese, zinc, chromium and cadmium, replace tin, nickel, copper and lead in the acid solution because the electrolytic solution pressure of the precipitating.

metals is so much greater than that of the precipitated metals that a condition of equilibrium is not reached until practically all of the tin, nickel,

lead or copper has been precipitated. The following equation illustrates this reaction:

sn++ Zn zn++ $11 Solution Metallic Solution Metallic The reduction potential of metallic zinc against a molal solution of zinc salt is +0.76 volt and of metallic tin against a molal solution of tin ions is 0.1; the minus sign means merely that there is more tendency for tin .ions to be deposited than for metallic tin to pass into solution. The greater the positive value of the reduction potential, the greater the electrolytic solution pressure. As the tin is deposited from the solution, its reduction potential gradually becomes greater and as the zinc passes into solution its reduction potential becomes smaller and smaller. It is evident, there'- fore, that equilibrium between the zinc and the tin solution will be reached only when the reduction potential of the zinc is equal to that of the tin.

The electromotive series shows the. relative value of the metals as reducing agents. The metals at or near the-top of the series, i. e., magnesium, aluminum, manganese, zinc, chromium and cadmium, being the most easily oxidized are the best reducing agents. The concentration of the solution also comes into consideration. If the reduction potentials are all measured against equivalent concentrations, then the order of the metals arranged in the electromotive series will correspond exactly to the order of the metals when arranged according to the values of their electrolytic solution pressures.

Therefore, the precipitation of tin from a tin solution by means of metallic zinc is due to the fact that the reduction potential or the electrolytic solution pressure of zinc is greater than that of tin.

In the case of many metals in providing an alloy of two or more, it is recognized that it is exceedingly difficult to provide an alloy of homogeneous character, and the degree of fineness of tion of these.

readily melted. However, when the two metals are together in the molten state, the one having the greater specific gravity tends to separate out, and often it is attempted to keep the molten mass stirred in order to avoid this natural separating, but obviously there is more or less gravity separation at best. Particularly are these observations true of tin, zinc and lead, or any combina- The same is also true of zinc, lead and copper or any combination of these. However, these difliculties are overcome with respect to all these metals, as well as any metal that may be broken down by an acid or a combination of acids, when treated in accordance with my invention. That is, metals to be al.- loyed, if comminuted through the medium of a spongelike mass as disclosed herein, will form an alloy particularly characterized by its homogeneity.

For plating purposes it is well recognized that different. alloys are characterized by different degrees of spreadability, i. e., they have a difierent degree of fluidity. When an alloy is formed according to the invention herein disclosed, it is greeof fineness of structure and this may further explain the high degree of fluidity, which strongly characterizes the alloy formed in accordance with my invention. This high degree of fluidity is particularly important in insuring a continuous coating and leaving no spot uncontacted with the plating coating. Furthermore, this advantage in the high degree of fluidity of metals is also provided by my invention for single metals as, for example, tin and lead.

It is well known that tin is characterized by a very high degree of absorbing or alloying with other metals. For example, a small quantity of tin, say eight parts by weight of tin, has the power of giving a white color to ninety parts by weight of copper. This constitutes the well known gun-metal. This is the least amount of tin according to present publications that will afiect the said amount of copper. However, tin

treated according to my invention has this abtwenty-five percent or more.

The homogeneity of the alloy resulting from treatment of tin, zinc and lead is evidenced by the fact that the melted metal when cooled has a gray aluminum colored frost coating. The appearance of such coating is generally accepted as indicating uniformity of alloy metals. The color of the bar becomes aluminum gray even through the entire mass, so that when the same is broken in two, the color has been uniformly changed from lead to aluminum color, even when the alloy results from treating eighty-five percent lead and fifteen percent tin and zinc compound.

It will be understood that the above sets forth the preferred methods of treatment and no attempt is made to cover all the slight variations which would readily suggest themselves to those skilled in the art, the above constituting the preferred methods of procedure and setting forth ing the rate of reacting upon zinc in extended integral form with a solution which includes tin dissolved in acid until from the reaction prod-.

ucts a gas distended, coherent, sponge-like body is developed about said zinc, said regulating including adjusting the force of reaction by changing the strength of the acid metal solution to the buoyant force of said solution upon the said sponge-like body so that said buoyant force is of a magnitude less than that required to detach said body from said zinc.

2. The process of making the composition of matter described comprising the step of regulating the rate of reacting upon zinc in extended integral form with a solution which includes tin comprising substantially 1.25 pounds of tin in substantially 10 pounds hydrochloric acid; diluting said solution with one hundred pounds of water; inserting in said solution substantially 1.375 pounds of metallic zinc as such in extended integral form, said diluting proportions operating to regulate the rate of reaction so that a gas distended, coherent, sponge-like body is formed of the reaction products of said metals;

removing said sponge-like body from the solution; and neutralizing the action of the acid upon the said sponge-like body.

4. The process of making the composition of matter described comprising the step of regulating the rate of reacting upon a metal in extended integral form by a solution which includes a second metal dissolved in an acid, said first metal being related to the second metal as a precipitant in the electromotive series, said reacting being allowed to continue until from the reaction products a gas distended, coherent, sponge-like body is developed about said first metal, said regulating including adjusting the force of reaction by changing the strength of the acid metal solution to the buoyant force of said solution upon the said sponge-like body so that said buoyant force is of a magnitude less than that required to detach said body from said first metal. 4

5. The process of making the composition of matter described comprising the steps of regulating the rate of reacting upon zinc in extended integral form with a solution which includes tin dissolved in hydrochloric acid, until from the reaction products a gas distended, coherent, sponge-like body is developed about said zinc, said regulating including adjusting the force of reaction by changing the strength of the acid metal solution to the buoyant force of said solution upon said sponge-like body so that said buoyant force is of a magnitude less than that required to detach said body from said zinc; removing said sponge-like body from the solution; neutralizing the solution in said body; and intermixing said body with an oil in viscous form, whereby a homogeneous paste is formed which is practically free of gravity separation.

ERNEST HEY.

Ill

' iso

Images