US1480779A - Composition of matter and method of making same - Google Patents

Description

' with a Patented 15 1924.

UNITED STATES 1,480,779 PATENT OFFICE.

ALADAR PACZ, OF CLEVELAND HEIGHTS, OHIO.

COMPOSITION OF MATTER AND METHOD OF MAKING- SAME.

is a substance of great value and importance in various technical uses, for example, in the production of high temperatures and the reduction of certain metals and alloys, and also in connection with the operation known as calorizing. "According to the first named use the powdered aluminum is mixed uantit of oxide of some metal or metals w ich a uminum will reduce, for example the oxide of iron or a metal similar to iron. Upon igniting the mixture, the reaction proceeds very rapidly with the production of an extremely high temperature,"

much needed in certain weldin operations. The result of this reaction is t e reduction of the oxide to metallic form and the process is often employed for the preparation of various metals and alloys, particularl the ferro-alloys, as well as the alloys of uminum with silicon, etc. Accordin to the second named use, the powdered a uminum is introduced into a closed container in company with iron or steel articles and tumbled for several hours at a temperature around 900 C. in a hydrogen atmosphere, whereupon the aluminum alloys with the surface of the ferrous metal in such wise as to protect the same in a very effective manner against oxidizing or corroding influences,

The preparation of such powdered aluminum has always been a matter of considerable difficulty. On account of its toughness, it has been found very difiicult to cut the metal mechanically into pieces of sufliciently small size, while its great malleability has prevented the employment of any grinding or crushing operations. It has been found possible by stirring the metal vigorously while cooling from a molten state to comminute it into small ains, and it is also possible by blowing a last of air through a stream of the molten metal to atomize it mto small particles, but in both cases the grains which I preferably employ Application filed larch 26, 1920. Serial No. 369,080.

are covered by a thin film of aluminum oxide. This oxide film renders it much more 'diflicult to start the alumino-thermic reaction than it is in case the metal particles are clean, and it impedes in astill more serious manner the process of calorizing.

The objects of my invention are the provision of a new, improved and simplified process whereby the necessary comminution can be effected and with the production of grains which are preferably free from oxide coating; the provision of a powder which will react more quickly .and easily for the production of heat or the reduction of metals than the aluminum powders ordinarily used and also result in a superior product; the provision of a reacting material which shall produce a more fusible sla than heretofore; while further objects an advantages will .become apparent as the description proceeds.

The essence of my invention consists in alloying the aluminum with some substance which shall render it sufliciently brittle to enable its reduction to the powdered condition by mechanical means, and without injuring its reaction. Silicon is the substance for this purpose in combination with the a uminumalthough other substances can 'be used in addition thereto. When'silicon alone is employed I preferably use an amount thereof equal to at least about 10 per cent of the resulting alloy, which causes the resulting alloy to become sufliciently brittle so that turnings or borings of the same can be .crushed in a ball mill much in the same way as cast iron borings. For reasons of economy and to avoid raising unduly the melting point of the alloy I prefer to restrain the amount of silicon to the smallest amount that will afford the desired brittleness, although the proportion can be increased to any desired amount. within the limits of practicable fusion.

I find it perfectly feasible for many uses to alloy the aluminum with ferro-silicon rather than with pure silicon preferably employin for the purpose a substance containing a ut 25 per cent of iron and 75 percent of silicon. 10 per cent of this substance combined with aluminum results in a sufliciently brittle alloy for practical powderin smce the iron content itself has a pose of generating additional heat asset forth in my application filed March 19, 1920, Serial No. 367,085 or substances which shall be of assistance in chemical combination in the later use of the material, such as nickel or chromium in connection with the calorizin operation.

My improved alloy may be produced in any convenient manner, as by merely melting together the pure ingredients in an-electricor other furnace, although I refer to e 1920, Serial ever, the oxidation. preventing quality of the silicon is such that the alloy can be blown if desired and the resulting grains will be oxide free; in this case, the silicon content can sometimes be reduced to a lower figure, say 5 per cent, the brittleness not being important but only the shielding quality of the silicon.

When employed in the welding operation,

my improved material is superior to blown or stirred aluminum powder in that the reaction can be started more easily and yields an equally high tem rature. When employed in the'production of metals and, al-' .loys, the high temperature generated by I the oxidation of the aluminum causes the silicon also to enter the reaction and assist the reduction thus serving the double purpose of producing a more fusible slag and more easily separable slag than is obtained when aluminum alone is employed (owing to the fact that the silica produced com-.

bines with the alumina to produce aluminum silicate which is much more fusible than pure alumina) and also prevents the con-, tamination of the alloys by the aluminum. It is found that most alloys produced by the alumino-thermic reaction contain a quantity of aluminum as an impurity, some of the same becoming alloyed with the metal instead of assisting in the reaction, but my experience indicates that alloying of the aluminum is less likely to occur in case silicon be present and although a small amount of the silicon will sometimes become alloyed with the resulting metal, its presence is much less objectionable than that of aluminum. For use in calorizing', my improved powder operates much better than the blown or stirred aluminum powder owing to the absence of any superficial oxide, added to which the silicon is of independent advantage as a constituent of the coating. The adhesion of the coating and its chemical quality can also be enhanced by the use in the powder of small quantities of iron, nickel, chromium or the like alloyed with the aluminum. I do' not restrict myself to the use of my improved composition of matter for the purposes herein mentioned but claim the same for all uses to which it may be applicable, and in general restrict myself in nowise except as specifically set forth inthe annexed claims. I

Having thus described my invention, what I claim 1s: a Y

1 A powdered alloy of aluminum and silicon containing at. least about 5 per cent of silicon and the balance mostly aluminum.

2. A powdered com ositionof matter active alumino-thermica ly consisting essentially ofaluminum alloyed with silicon, theamount'of materials other than aluminum an essential constituent which contains thestep of alloying the aluminum with at least about 5 per cent of silicon and subsequently reducing such alloyto powdered form in any of the modes heretofore employed in th case of pure aluminum. V

In testimony whereof, I hereunto afiix my signature. I

ALADAR PACZ.

ilicon being res- 4