Molybdenum, Tungsten, Vanadium and Chromium

The elements that decrease the extent of the austenite field include chromium, siUcon, molybdenum, tungsten, vanadium, tin, niobium, phosphoms, aluminum, and titanium. These are known as ferrite stabilizers. 

The addition of carbide stabilizers to steel reduces the tendency toward internal Assuring. Elements such as chromium, molybdenum, tungsten, vanadium, titanium, and niobium reduce the number of nucleation sites by forming more stable alloy carbides which resist breakdown by hydrogen and, therefore, decrease the propensity to form methane.9 The solid-line curves in Figure 1 reflect the increased resistance to internal attack when molybdenum and chromium are present. 

Iron-chromium alloys, free from carbon, may be prepared from chromite by the alumino-thermic method. From a study of the cooling-and freezing-point curves it has been suggested that a compound, Cr Fe, exists, but this is questioned by Janecke, who studied the iron-chromium system by means of fusion curves and by the microscopic study of polished sections of various alloys between the limits 10 Fe 90 Cr and 90 Fe 10 Cr, and came to the conclusion that the system consists of a single eutectic which can form mixed crystals with either component. The eutectic contains 75 per cent, of chromium and melts at 1320° C. The addition of chromium to iron increases the readiness of attack by hydrochloric and sulphuric acids, but towards concentrated nitric acid the alloys are rendered passive. They remain bright in air and in water. The presence of carbon increases the resistance to acids and renders them very hard if carbon-free, they are softer than cast iron. All the alloys up to 80 per cent, chromium are magnetic. Molybdenum, titanium, vanadium, and tungsten improve the mechanical properties and increase the resistance to acids. 

A.P.G. Gervasio, G.C. Luca, A.A. Menegario, B.F. Reis, H. Bergamin-Filho, On-line electrolytic dissolution of alloys in flow injection analysis. Determination of iron, tungsten, molybdenum, vanadium and chromium in tool steels by inductively coupled plasma atomic emission spectrometry, Anal. Chim. Acta 405 (2000) 213. 

Chromium, tungsten, vanadium and molybdenum plumbites 360-400 Toluene Benzaldehyde Benzoic acid (54)... 

Figure 12.22 In the fourth period, vanadium and chromium have very similar melting points. Molybdenum and tungsten have the highest melting points in the fifth and sixth periods, respectively. All of these elements are located near the middle of the period where the bonding orbitals are mostly filled and the antibonding orbitals mostly empty.

Some of the most commonly used metals deposited by sputtering are aluminum, copper, chromium, gold, molybdenum, nickel, platinum, silver, tantalum, titanium, tungsten, vanadium, and zirconium. 

For the polymerization of cyclobutene, Natta and coworkers [37] reported binary catalytic systems containing titanium, vanadium, chromium, and tungsten to be the most active, those of molybdenum less active, and systems derived from cobalt, iron, manganese, and uranium totally inactive. Catalysts based on vanadium and chromium yield preferentially polycyclobutylene by addition polymerization, those with molybdenum and tungsten give polybutenamer by ring-opening... 

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