Nov., 1912 1
T H E JOLJ-R.\~AL OF I A - D U S T R I A L A.VD EhTGIi\TEERISG C H E X I S T R Y .
2 parts, copper 5 parts, silicon I part, be melted and added to 92 parts of melted aluminum, this alloy will resist acid.
THE SCHOOP METALLIZING PROCESS. Gradenwitz (Sci. A m . , 107, 224) states that although the Schoop metallizing process was announced sometime ago, yet the details of the process and apparatus have just been made public. According to Gradenwitz, in the first metallizer constructed by Schoop, molten metal mas pulverized by a jet of high pressure steam, and projected in a stream of spray upon the object to be coated with metal. This, however, required a stationary apparatus. In the portable apparatus, the molten metal is replaced by a metal powder, which is carried along by a jet of steam or of compressed gas. The jet of gas is heated either by means of a flame or an electric resistance or arc. The particles of metal powder are shot out of the apparatus by means of a jet. The object to be coated with the metal is thus bombarded with fine metallic particles. At the moment they strike the surface there occurs a transformation of live energy into heat, and this heat contributes to liquefying the particles so as to solder them to one another. A very convenient form of portable apparatus is represented in the diagram. The mouth-piece C, from which the iet heated by a gas flame is blown forth, is fixed a t the end of a flexible tube. The gas enters through the valve 2 , into a n inner tube fitting concentrically with the passage 7 . The air, which is generally a t a pressure of five atmospheres, passes through the tube I, into a chamber fitted with two valves, 3, and 4. By turning the valve 3 compressed air is admitted directly into the passage 7, and by operating the valve 4 it is led into the lower half of the apparatus, where it produces a whirl of Details of the apparatus for depositing metal powder, carrying along pulverized metal. some of the powder into the conduit 6 , then into the conduit 7 , and finally into the flexible tube connected with the mouth-piece. The apparatus is mounted to turn on a horizontal axis, so that the last traces of metal may be removed by the compressed air, by tipping the apparatus on its axis. The apparatus is started by opening the gas valve z and igniting the gas. The compressed air admission having been opened, the valve 3 is adjusted until a satisfactory flame is obtained. Then the valve 4 is opened so as to introduce the metal powder. In order to insure a really homogeneous layer, it is essential that no oxide film covers the particles. A striking feature of the operation is that the expansion of the gas is a t tended by a strong cooling Tvhich solidifies the metal rapidly, while the surface temperature remains low; in fact, n i t h such metals it is below 60’ C. I t is claimed that inflammable substances, like celluloid, as well as flowers and fruits can be metallized. The thickness of the deposit may vary between a hundredth of a millimeter and several millimeters, depending upon the surface to be coated, and on the relative speed of the jet. The latter also governs the hardness and density of the metal coating. This system of metallizing has been used for forming accumulator plates; constructing resistances in the form of a metal thread of zig-zag shape; obtaining electric contacts instead of soldering them; and metallizing the clothes of electricians.
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THE STATE OF THE ANTIMONY MARKET. While 7 j tons of antimony ore were produced in the United States in 1910,this was entirely used for experimental purposes; and in 1911 there was no production, notwithstanding the fact that the antimony imported in the form of ore, regulus or metal amounted to 1o,gjj,844pounds. This was in part to be attributed to the low price ($0.08 per pound) a t which the antimony was selling, but in the main to the high requirements for ore, namely, 50-60 per cent. antimony content. There is a great possibility that the ores of Nevada and Arkansas may be utilized in the near future, for there are mines capable of furnishing the American demand and successful experiments have already been made to increase the grade of production; but the market must be strong and the prices higher than those of the past year. I n October, dealers in antimony, which is extensively used in this country-antimonial lead being largely used by manufacturers of type metals, babbitt metals, and metal novelties; the sulphide in medicine; and the oxide in the ceramic and enamel industries-quoted Cookson’s brand a t So. 10125 per pound, Hallett’s a t $o.ogj, and Chinese, Hungarian and other outside grades a t $0.09. The demand was good, but the advance in price was ascribed to a scarcity of ore. The largest producer, China, where the condition of the antimony industry has been changing rapidly during late years, is now reported as having about exhausted its deposits; if this is found to be correct, according to a prominent firm, “me shall see a high antimony market until some country is found to take the place of China as a producer of antimony ore.” While the production of Germany, Hungary, Italy, and Turkey has been considerable, the prospects for American production appear to be brighter than hitherto. POROUS METALS. Hannover (Comfit. rend., 154, 1594) finds that when a binary alloy containing a greater percentage of the one component than corresponds with the eutectic composition is centrifugalized while in the somewhat pasty condition, the eutectic can be expelled, leaving the component in excess in a porous state. Using a n alloy of lead and antimony containing go per cent. of lead, and one of tin and lead containing 80 per cent. of tin, Hannover obtained both porous lead and porous tin. In a similar manner, from an alloy of lead with an excess of antimony, porous antimony mas obtained. I t is stated that the porous lead so obtained may be employed in making accumulator plates of very large capacity. According to a Berlin correspondent (Scz. Am. Suppl., 74, 133), exhaustive tests of accumulator plates made from such porous metal, conducted a t the central n-orkshops of the Danish State Railway, have shown the new type of plate to give very great capacities. Whereas the means of increasing the surface of accumulator plates so far employed (perforating and ribbing) a t the most give a surface 8 times as large as the natural surface, Hannover has been able by his process to increase the natural surfacc about 130 fold, the number of hollows being 20 per millimeter. Porous metals could also be used for filtering; as bearing-metal, the oil being fed through the pores; for plugs in conduits containing explosive gases; as catalyzers for chemical reactions; etc. PEAT FUEL FOR THE PRODUCTION OF POWER. Large supplies of peat are available in Portadown, Ireland, and Engineering News, 68, 520, states that a plant there has run since September, 1911,on this fuel, which is fired as it comes from the drying yard. On a test producer run of 6 hours duration, with a load of 2 j o B. H. P., the peat consumption averaged 2.55 pounds per B. H. P. hr. with a fuel containing 18.98 per cent. of water. Two producers were running and the loads were considerably below the total capacity of the plant, this
