Alloys containing vanadium

Silicon Reduction. The preparation of ferrovanadium by the reduction of vanadium concentrates with ferrosiUcon has been used but not extensively. It involves a two-stage process in which technical-grade vanadium pentoxide, ferrosiUcon, lime, and fluorspar are heated in an electric furnace to reduce the oxide an iron alloy containing ca 30 wt % vanadium but undesirable amounts of siUcon is produced. The siUcon content of the alloy is then decreased by the addition of more V2O5 and lime to effect the extraction of most of the siUcon into the slag phase. An alternative process involves the... 

Compared to that prepared by cirect electron-beam melting of vanadium alloy containing 15 wt % aluminum. 

The high-chromium casting alloys (50% nickel, 50% chromium and 40% nickel, 60% chromium) are designated for use at temperatures up to 900 C in furnaces and boilers Ared by fuels containing vanadium, sulfur and sodium compounds (e.g., residual petroleum products). Alloys with lower chromium contents cannot be used with residual fuel oils at temperature above 6S0 C because the nickel reacts with the vanadium, sulfur and sodium -impurities to form compounds that are molten above 650 C [27]. 

The benefit of vanadium as an additive in steel is that it forms V4C3 with any carbon present, and this disperses to produce a finegrained steel which has increased resistance to wear and is stronger at high temperatures. Such steels are widely used in the manufacture of springs and high-speed tools. In 1995, world consumption of vanadium metal, alloys and concentrates exceeded 33 000 tonnes of contained vanadium. 

The corrosion behaviour of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous iron-chromium-metalloid alloys was reported. The majority of amorphous ferrous alloys contain large amounts of metalloids. The corrosion rate of amorphous iron-metalloid alloys decreases with the addition of most second metallic elements such as titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, copper, ruthenium, rhodium, palladium, iridium and platinum . The addition of chromium is particularly effective. For instance amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 N HCl at ambient temperature ". (The number denoting the concentration of an alloy element in the amorphous alloy formulae is the atomic percent unless otherwise stated.)... 

Niobium-Vanadium The presence of vanadium reduces niobium s corrosion resistance to most media. The alloy containing 12 6 at. Vo V however has excellent resistance to high-temperature water and steam, and this property and the alloy s relatively low neutron cross section give it considerable potential for nuclear applications. 

Ferro-alloys Master alloys containing a significant amount of bon and a few elements more or less soluble in molten bon which improve properties of bon and steels. As additives they give bon and steel better characteristics (increased tensile sbength, wear resistance, corrosion resistance, etc.). For master alloy production carbothermic processes are used for large-scale ferro-sihcon, ferro-chromium, ferro-tungsten, ferro-manganese, ferro-nickel and metallothermic processes (mainly alumino and sihco-thermic) for ferro-titanium, ferro-vanadium, ferro-molybdenum, ferro-boron. 

For industrial purposes vanadium is not required in the elemental state. More than 90 per cent, of the world s production of vanadium is used in the manufacture of special steels, for which purpose an iron-vanadium alloy, known as ferrovanadium, containing from 80 to 40 per cent, of vanadium, is marketed. The method of manufacture of this alloy from vanadium-bearing ores varies considerably with the composition of the ore and the value of the by-products. The process is conveniently divided into two stages ... 

Copper.—Alloys of copper and vanadium are prepared by firing a mixture of vanadium pentoxide, copper oxide, aluminium shot, lime, soda-ash, and fluorspar with the aid of sodium peroxide in a magnesia-lined crucible.2 Electrolytic methods have also been employed, and are applicable for the preparation of other vanadium alloys.3 An alloy containing 3-38 per cent, of vanadium and 96-52 per cent, of copper was found to be harder than copper and could be drawn into wire. An aluminium-copper-vanadium alloy has been prepared.4... 

Steel is an alloy containing chromium, manganese, molybdenum, nickel, vanadium and boron. Copper-nickel alloy, bronze and aluminium alloys are used in making coins. Fusible alloys having low melting points are used as solder and fuses in electrical circuits. 

Despite being a net importer of raw vanadium materials, the United States has remained an exporter of processed vanadium products. The United States exports vanadium principally in the form of vanadium pentoxide, which is the primary source for the production of chemicals, catalysts, alloys, and other vanadium compounds. Vanadium pentoxide and catalysts containing vanadium pentoxide have accounted for between 61% (1987) and 82% (1984) of all domestic exports. In 1984, the United States exported a total of 4,498 tons of vanadium. Since then, exports have declined, reaching a level of 2,486 tons in 1986 and remaining fairly constant through 1987. The major importers of vanadium from the United States are Canada, the Federal Republic of Germany, Japan, and Mexico. These are followed by Taiwan and the Republic of Korea (Hilliard 1987). 

During the latter part of 1918 ferrovanadium sold for 5 per pound of contained vanadium. During 1919 the demand was strong, and the price rose to 7 or more per pound for the alloy low in both carlmn and silicon. The demand was so strong that the alloy with a high oarhon and silicon content sold freely, and for the first time purchasers of earnotito were compelled to pay for the vanadium which it. contained. During the latter part of 1920 the market became dull, possibly due to... 

Vanadium forms alloys with other metals, some of which are of considerable commercial interest. The aluminium alloys containing 10 per cent or less of vanadium are malleable, while those containing 20-25 per cent vanadium may be pulverized in water. The alloy of the composition A1V is the hardest one of the series. A copper-vanadium alloy containing 10-15 per cent vanadium, 60-70 per cent copper, 10-15 per cent aluminium, and 2-3 per cent nickel is prepared and used for the production of solid copper castings and bronzes and in the manufacture of aluminium alloys. Approximately 100 tons of cupro-vana-dium are sold annually to brass and bronze makers.1 Vanadium is also used to harden gold for use in dentistry. 

X 10 M solution of the vanadium complex exhibits absorbances of 0.400 and 0.600 at 415 and 455 nm, respectively. A 1.000-g sample of an alloy containing titanium and vanadium was dissolved, treated with excess hydrogen peroxide, and diluted to a final volume of 100 mL. The absorbance of the solution was 0.685 at 415 nm and 0.513 at 455 nm. What were the percentages of titanium and vanadium in the alloy ... 

Dilute Fe-Cr alloys show similar nearest-neighbour effects to the corresponding vanadium alloys [36-38]. Quenched samples of the FcaCr alloy containing 0-01% of Nj have been found to contain small proportions of an as yet unidentified non-magnetic phase [39]. 

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