- Email: [email protected]
Titanic acid in underglaze colors
12 4
CURRENT TOPICS.
being fibrous, while the latter are granular. Examination of the filaments after burning in lamps for 500 hours with either a continuous current, producing a temperature of about 19oo ° C., or an alternating current of 42 cycles, shows that in both cases the metal is transformed into the micro-crystalline condition, just as has been previously shown to occur with the old filaments produced from the oxide. Drawn tungsten filaments should, therefore, be much more durable than drawn tantalum filaments, which form larger crystals under the combined action of temperature and vibration. ' i E x p l o s i o n of H y d r o g e n Cylinders. LELARGE. (Comptes Rendus, clv; 9 1 4 . ) - - T w o men were killed in 1911 while measuring the gas pressure of hydrogen in a steel cylinder. Apparently the explosion was due to the rapid compression of the air in the tube connecting the cylinder to the gauge. In experiments conducted in the Laboratoire d'Aeronautique Militaire the cylinders were placed inside a strong steel cage built up of hoops and tie-rods, and a pipe packed with disks was interposed between the cylinder and the gauge to take up any heat generated by a minor gas combustion within the gauge. The gas pressure was first determined with the safety tube in position; the gas was then analyzed, and the pressure re-determined without the safety device; explosion occurred when the hydrogen was sufficiently impure. In practice all cul-de-sac connections should be avoided or be arranged like a safety tube, and the density of the gas should be measured before taking the pressure. Great care is needed in dealing with heavy hydrogen, probably containing air or oxygen, especially if electrolytic. Titanic Acid in U n d e r g l a z e Colors. A. BERGE. (Sprechsaal, xlvi, 2 o 6 . ) - - T h e color produced by a stain depends, to some extent, on the reaction of the other constituents on the chief coloring oxide. Cobalt, for example, gives a deep dark-blue with silica and a sky-blue with alumina. The tints are further affected by zinc oxide, phosphoric acid, etc. The component oxides of a stain may be intimately mixed by fine grinding, by precipitation of the hydroxides, by melting together of sulphates in their water of crystallization, or by Pukall's " suction " method, in which soluble salts of coloring oxides are absorbed by kaolin, etc., and then calcined and ground. Titanic acid is recommended as a carrier for other coloring oxides. Trials were fired in majolica, stoneware, and porcelain kilns, of rutile thus used with the oxides of uranium, cobalt, iron, nickel, copper, manganese, chromium, molybdenum and tungsten. A wide range of colors was obtained from yellow to blue-black. The best results for underglaze, when using titanic acid alone, were obtained at cone 7--9 for olive-green, brown, and yellow tints.
CURRENT TOPICS.
being fibrous, while the latter are granular. Examination of the filaments after burning in lamps for 500 hours with either a continuous current, producing a temperature of about 19oo ° C., or an alternating current of 42 cycles, shows that in both cases the metal is transformed into the micro-crystalline condition, just as has been previously shown to occur with the old filaments produced from the oxide. Drawn tungsten filaments should, therefore, be much more durable than drawn tantalum filaments, which form larger crystals under the combined action of temperature and vibration. ' i E x p l o s i o n of H y d r o g e n Cylinders. LELARGE. (Comptes Rendus, clv; 9 1 4 . ) - - T w o men were killed in 1911 while measuring the gas pressure of hydrogen in a steel cylinder. Apparently the explosion was due to the rapid compression of the air in the tube connecting the cylinder to the gauge. In experiments conducted in the Laboratoire d'Aeronautique Militaire the cylinders were placed inside a strong steel cage built up of hoops and tie-rods, and a pipe packed with disks was interposed between the cylinder and the gauge to take up any heat generated by a minor gas combustion within the gauge. The gas pressure was first determined with the safety tube in position; the gas was then analyzed, and the pressure re-determined without the safety device; explosion occurred when the hydrogen was sufficiently impure. In practice all cul-de-sac connections should be avoided or be arranged like a safety tube, and the density of the gas should be measured before taking the pressure. Great care is needed in dealing with heavy hydrogen, probably containing air or oxygen, especially if electrolytic. Titanic Acid in U n d e r g l a z e Colors. A. BERGE. (Sprechsaal, xlvi, 2 o 6 . ) - - T h e color produced by a stain depends, to some extent, on the reaction of the other constituents on the chief coloring oxide. Cobalt, for example, gives a deep dark-blue with silica and a sky-blue with alumina. The tints are further affected by zinc oxide, phosphoric acid, etc. The component oxides of a stain may be intimately mixed by fine grinding, by precipitation of the hydroxides, by melting together of sulphates in their water of crystallization, or by Pukall's " suction " method, in which soluble salts of coloring oxides are absorbed by kaolin, etc., and then calcined and ground. Titanic acid is recommended as a carrier for other coloring oxides. Trials were fired in majolica, stoneware, and porcelain kilns, of rutile thus used with the oxides of uranium, cobalt, iron, nickel, copper, manganese, chromium, molybdenum and tungsten. A wide range of colors was obtained from yellow to blue-black. The best results for underglaze, when using titanic acid alone, were obtained at cone 7--9 for olive-green, brown, and yellow tints.