Silicon-iron alloys continued

Aluminum iodide pentadecahydrate, 2 386 Aluminum-iron alloys, 2 308-309 Aluminum-iron-silicon alloys, 2 316-317 a-Aluminum-iron-silicon alloys, 2 317 intermetallic phases, 2 316t P-Aluminum-iron-silicon alloys, 2 317 intermetallic phases, 2 316t Aluminum-killed steel, continuous-cast,... 

The high-chromium irons undoubtedly owe their corrosion-resistant properties to the development on the surface of the alloys of an impervious and highly tenacious film, probably consisting of a complex mixture of chromium and iron oxides. Since the chromium oxide will be derived from the chromium present in the matrix and not from that combined with the carbide, it follows that a stainless iron will be produced only when an adequate excess (probably not less than 12% of chromium over the amount required to form carbides is present. It is commonly held, and with some theoretical backing, that carbon combines with ten times its own weight of chromium to produce carbides. It has been said that an increase in the silicon content increases the corrosion resistance of the iron this result is probably achieved because the silicon refines the carbides and so aids the development of a more continuous oxide film over the metal surface. It seems likely that the addition of molybdenum has a similar effect, although it is possible that the molybdenum displaces some chromium from combination with the carbon and therefore increases the chromium content of the ferrite. 

The conditions which affect the type of reaction are bath temperature and the composition of iron or steel which is being coated. At 480-520°C the reaction between iron and zinc can be linear with time so that the thickness of the alloy layers will increase in direct proportion to the immersion time and the reaction will continue to be relatively rapid. With some steels (e.g. some silicon-killed steels), the reaction can be linear at the normal galvanising temperature of about 450 C. 

Aluminum spraying is used to coat less corrosion-resistant alloys. In the case of some composites, corrosion is due to the galvanic action between the aluminum matrix and the reinforcing material. Aluminum thermal spraying has been successfully used for the protection of the discontinous silicon carbide/aluminum composites, and continuous graphite/aluminum. Other protection procedures include sulfuric acid anodizing and iron vapor deposition on aluminum.44... 

Mr. Raney continued to research on his catalyst from the time it was discovered until he died. He was granted a total of six U. S. Patents and five foreign patents. In addition to the two basic patents that issued prior to 1930, he obtained a patent for the preparation of granular catalysts made from aluminum and silicon alloys containing metals such as iron, cobalt, copper and nickel (15), a method for reclaiming spent catalyst (16), the production of a nonpyrophoric catalyst (17) and a catalyst prepared from a mixture of nickel and a nickel-aluminum alloy (18). A list of his inventions is given in Table 1. Over the... 

For more than a century, a number of different aluminum alloys have been commonly used in the aircraft industry These substrates mainly contain several alloying elements, such as copper, chromium, iron, nickel, cobalt, magnesium, manganese, silicon, titanium and zinc. It is known that these metals and alloys can be dissolved as oxides or other compounds in an aqueous medium due to the chemical or electrochemical reactions between their metal surfaces and the environment (solution). The rate of the dissolution from anode to cathode phases at the metal surfaces can be influenced by the electrical conductivity of electrolytic solutions. Thus, anodic and cathodic electron transfer reactions readily exist with bulk electrolytes in water and, hence, produce corrosive products and ions. It is known that pure water has poor electrical conductivity, which in turn lowers the corrosion rate of materials however, natural environmental solutions (e g. sea water, acid rains, emissions or pollutants, chemical products and industrial waste) are highly corrosive and the environment s temperature, humidity, UV light and pressure continuously vary depending on time and the type of process involved. ... 

Usefulness of the red metal is in the same class as that of iron. It is a mainstay of the modern industrial world. Electrical applications dominate, but it is also an important ingredient of alloys used for structural and decorative applications. The formation of a thin oxide on copper does not pose the electrical problem encountered with aluminum or silicon. Current passes quite easily through the oxide. Extensive corrosion of alloys, however, is a continuing problem. 

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