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Uranium-nickel metal alloy phosphates, citrates, acetic acid-acetate compounds, in a non-oxidising atmo mixtures, bicarbonates, or dichromates, sphere at approximately 1,000°. Pre A binary alloy having the formula borax, nitrates, ferricyanides, and a ferably the Si-containing layer obtained U Ni is claimed to have corrosion wetting agent. The percentage of is heated to temperatures just below resistance superior to U metal. The ingredients can be varied in formulas its m.p. and is then cooled rapidly. eutectic containing 37 atm.% Ni melts to give a pH of 3.5 to 10, with best Thus, a Fe-Mo alloy with 7% Mo was at 730° and is useful in the formation results claimed in the range of 6 to 8 treated in an O and water-free H atmo of more complex U alloys, where for most compositions. The range of sphere containing 5% by volume SiCl corrosion resistance is essential such 4 effective concentration is wide, e.g. for 10 min. at 1,100°. An Fe Si layer of as in the construction of atm. reactors. 3 from 0.01% by weight to saturation. approximately 0.18 mm. thickness and —U.S. Pat. 2,692,823, Marion E. Parts to be cleaned should be electro a zone of dense Fe-Mo silicide precipi Cieslicki and Benny J. Nelson. lysed dominantly as the anode in the tations of approximately 0.05 mm. ratio of 2: 1 to 8: 1 with 2 to 24 cycles thickness was formed. In the same Passivating agents per min. at 3 to 20 v. and temperatures manner a steel with 0.03 C was Aqueous solutions of nitrites, CrO , up to 180°F.—U.S. Pat. 2,685,564, siliconised to obtain an Fe Si layer of or chromates and sequestration agents Robert A. Emmett Jr. and Wilbur H. approximately 0.1 mm. thickness which such as pyre-, meta-, or polyphos Petering. steel had been mclybdenised previously phates or aminopolycarboxylic acids in a bath of molten Na,MoO for 12 of the trilon type are used as passivating hours at 980°. In a similar way steels Anti-rust electron-beam tube agents in the after-treatment of phos- have been siliconised which had been An electron-beam tube is manu phated metal (particularly Fe, steel, covered with a W and an Mo layer, factured comprising an Fe cone and a or Zn) surfaces to improve their corro respectively, by metal-spraying and glass window joined along its rim to sion resistance. A suitable passivating vaporising, respectively. Typical the large end of the cone. It is solution containing, besides NaNO , articles to be subjected to this treat difficult to provide the window with a Na CO 1 to 10, trilon 1 to 5, or ment are tubes, turbine blades, and 2 3 fluorescent screen by sedimentation neutral Na pyrophosphate 1 to 10 g./l., screws.—Austrian Pat. 179,-456, Erich without affecting and giving rise to the is applied by dipping or spraying. The Fitzer. forming of rust spots upon the screen. passivating treatment is carried out at These difficulties are now prevented normal or moderately elevated tem Condenser for separated by joining the window to the cone by perature, e.g. for about 20 sec. at 50°. liquefied gases use of a thin layer of mechanically and Sheet iron pickled with 30% HC1 for The packing for the condenser chemically resistant enamel with a 20 sec. at 20° is phosphated with a consists of 0.34 mm. Fe plate coated high m.p. This layer extends along 1.5% H PO solution for 1 min. at 50° 3 4 with 0.03 mm. of Al. The product is the cone from the joining rim to a and then dipped for 40 sec. in a bath corrosion-resistant and has 92% of the height somewhat above the level of the containing 1% of a 1:4 Na2CO - sedimentation liquid in applying the heat capacity of Fe.—Jap. Pat. 108 NaNO mixture and 1.75 g./l. trilon B. fluorescent screen. If, e.g. the liquid (1954), Ryutaro Inaga. It is then rinsed with cold water and layer is 6 to 8 cm. the breadth of the dried. An aqueous solution containing Corrosion-resistant alloy for use strip should be 7 to 9 cm.—Dutch Pat. Na2CrO 0.5 and neutral Na pyro in synthesis of urea 74,003, N. V. Philips' Gloeilampen- phosphate 4 g./l. is likewise suitable fabrieken. The alloy contains Co<25, Cr 20 to as a passivating bath.—Ger. Pat. 30, Mo 0.5 to 5.0, Ni 0.5 to 5.0, N 825,041, Metallgesellschaft A.-G. 0.1 to 0.5%, rest Fe. It may contain (Inventors, Helmut Ley, Walter Stenger Removing rust and inhibiting Mn< 2 and P and S<0.1%, respec and Willi Werner). further rusting tively as impurities. It may also con Rust stains on Cr-plated Fe and tain Si<3 , Cu< 3 and (or) Ti<0.6% . Corrosion-resistant alloy steels steel are removed by wiping with a —Jap. Pat. 6601 (1953), Toshio Ikejima. moist cloth and a mixture of tricalcium Alloy steels which are freely machin silicate and tricalcium aluminate. The able and corrosion-resistant contain Phenol-aldehyde resin salts dissolve the Fe rust and then are Cr 21 to 9, Ni 4 to 6, S 0.1 to 0.75, Mn compositions converted to a hydrated silica com max. 0.4% (preferably less than 0.2%) These compositions protect ferrous pound which fills the porous spaces in and Cu in the amount of at least five materials against corrosion. They are the Cr plating and prevents further times the S content.—U.S. Pat. made from a soluble Novolak resin, rusting.—U.S. Pat. 2,690,983, Joseph 2,689,177, Geo. H. Botham, John F. FeCl , a plasticiser, and alkali. They G. Meckler and Maurice C. Meckler Lancaster and David W. Outram act with the rust on the iron surface to (to Kromite Products Co.). (to A.P.V. Co. Ltd.). form a coloured, protective coating. A typical mixture comprises a soluble Siliconising iron alloys Electrolytic cleaning of steel Novolak resin dissolved in a solvent such as methanol or diacetone alcohol; A process is described for removing Si-containing protective layers which FeCl preferably 15 to 25% of the oil and smut from steel by applying an are hard and corrosion- and acid- resin; a dilute solution of NH , 1 to asymmetrically reversed electric resistant are made on Fe metals by 6% of the resin; and a plasticiser such current to the parts immersed in an treating the articles, which contain as tricresyl phosphate or dibutyl aqueous solution of a cleaning com Mo and (or) W in amounts >3 % or phthalate, 5 to 15% of the resin by pound or mixtures of cleaning com have been given a surface layer of this weight.—Brit. Pat. 695,552 (1950), pounds selected from the group composition, e.g. by spraying, plating W. E. A. Simon, Brycel Ltd. consisting of polyphosphates, mono or diffusion, with volatile Si-halogen 132 CORROSION TECHNOLOGY, April 1955
Anti-Corrosion Methods and Materials – Emerald Publishing
Published: Apr 1, 1955
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