Nickel continued temperature effects

The use of equipment close to the temperature at wliich the material was diffusion treated will result in continuing diffusion of chromium, aluminum etc., into the substrate, thus depleting chromium with consequent loss in oxidation and corrosion resistance. For aluminum, this effect is noticeable above 700°C in steels, and above 900°C in nickel alloys. For chromium, the effect is pronounced above 850°C for steels and above 950°C for nickel alloys. 

Neopentyl alcohol (continued) effect of pyridine, 35 344 effect of sodium, 35 342 effect of temperature, 35 339, 341 mechanism, 35 347 over nickel-kieselguhr, 35 348 Nemst s law, 40 117 Neutral ligands... 

In 1897, Sabatier and Senderens ( ) made a pioneering study of the use of a nickel as a catalyst for the hydrogenation of ethylene (ethene) to ethane. This investigation led to the award of the Nobel Prize to Sabatier in 1912. Since that time the importance of heterogeneous catalysts has continued to increase greatly, decade by decade, extending the boundaries of laboratory chemical researches and promoting new and more cost-effective processes within the chemical industry (2). The correct choice of a catalyst allows a desired reaction to proceed under milder conditions of temperature and pressure than would be... 

The effect of reaction conditions (temperature, pressure, H2 flow, C02 and/or propane flow, LHSV) and catalyst design on reaction rates and selectivites were determined. Comparative studies were performed either continuously with precious-metal fixed-bed catalysts in a trickle-bed reactor, or batchwise in stirred-tank reactors with supported nickel or precious metal on activated carbon catalysts. Reaction products were analyzed by capillary gas chromatography with regard to product composition, by titration to determine iodine and acid value, and by elemental analysis. 

When constructing electrolyzers for this process it is rather difficult to find suitable materials which can resist the effects of fluorine as it attacks most metals even at normal temperature fortunately continuous fluoride coatings are formed on the surface of some metals which protects them against further corrosion at least to a certain extent. Such metals are iron, nickel, Monel metal, aluminium and its alloys, magnesium and especially electron one of its alloys. However, the protective films are only stable at lower temperatures. At elevated temperatures a violent reaction proceeds between the fluorine and the metal. Monel metal and copper have relatively the best resistance against fluorine at elevated temperatures. These metals, therefore, were widely used to construct electrolyzers. In more recent designs, copper was replaced by steel or electron. 

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