Tungsten cobalt metals

Syntheses from Dry Metals and Salts. Only metaUic nickel and iron react direcdy with CO at moderate pressure and temperatures to form metal carbonyls. A report has claimed the synthesis of Co2(CO)g in 99% yield from cobalt metal and CO at high temperatures and pressures (91,92). The CO has to be absolutely free of oxygen and carbon dioxide or the yield is drastically reduced. Two patents report the formation of carbonyls from molybdenum and tungsten metal (93,94). Ruthenium and osmium do not react with CO even under drastic conditions (95,96). 

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.)... 

Rautala, P., and J. T. Norton Tungsten-Cobalt-Carbon System. J. Metals... 

The reaction is typically performed in diethyl ether, and the dication is precipitated as a red-brown solid or oil. Mixed-metal molybdenum-cobalt and tungsten-cobalt systems have also been obtained by this technique.75,76... 

The strong chemical reactivity of phosphorus allows the formation of single and mixed phosphides with several metals (7-10). Phosphides that are relevant to hydrotreating catalyst formulations (Table II) involve bonding of phosphorus with molybdenum (or tungsten), cobalt, and/or nickel. 

Figure 16 Comparison of observed (open) and calculated (solid) depletions of phosphorus, tungsten, cobalt, nickel, molybdenum, and rhenium (circles) together with those for gallium, tin, and copper (inverted triangles) (sources Righter and Drake, 1997, 1999, 2000). The calculated depletions utilize the partitioning expressions of Righter and Drake (1999) for conditions of 2,250 ( 300) K (1,973 °C), 27 ( 6) GPa, AIW = — 0.4 ( 0.3) between a hydrous peridotite (NBO/t = 2.65) magma ocean and metallic liquid. The observed depletions are those of McDonough and Sun (1995), but volatility corrected as described by Newsom and Sims (1991), where the correction is made based on comparisons to trends of lithophile volatile element depletions.

Cobalt metal with tungsten carbide fumes... 

Several years ago transition metal mediated reactions in the area of C-glycoside synthesis were primarily limited to palladium and to a lesser extent nickel and manganese. Over the last few years several other metals, including chromium, molybdenum, tungsten, cobalt, and rhodium, have been utilized in C-glycoside synthesis. This section discusses the chemistry of palladium, which is divided into Stille-type couplings and 7T-allyl complexes. This is followed by considerations of the chemistry of chromium and the above-listed metals. A review by Frappa and Sinou entitled Transition Metal Catalysed Fimctionalization at the Anomeric Center of Carbohydrates appeared in early 1997 [55]. 

Cobalt metal with tungsten carbide Group 2B Agents and groups of agents 20A33... 

Cobalt metal without tungsten carbide 20A33... 

Cobalt metal with tungsten carbide (Vol. 86 in preparation)... 

The cemented carbides are large-particle composites. These materials are used as cutting tools to machine hard steels. The first cemented carbide made was formed of tungsten carbide particles embedded in a matrix of cobalt metal. The hard carbide cuts the steel but is brittle. The toughness comes from the cobalt matrix. 

The story of mankind is intimately hnked to the discovery and successful use of metals and their alloys. Amongst them iron and steel - we could define steel as a generally hard, strong, durable, malleable alloy of iron and carbon, usually containing between 0.2 and 1.5 percent carbon, often with other constituents such as manganese. Chromium, nickel, molybdenum, copper, tungsten. Cobalt, or silicon, depending on the desired alloy properties, and widely used as a stractural material , have shaped our material world. 

In such a process, zinc metal is added and melted with clean cemented carbide scrap cobalt is dissolved in the molten zinc, zinc is distilled off, leaving a spongy cake easily crushed, milled and screened to separate the cobalt metal powder and the hard carbide (tungsten, tantalum and other carbides) grains. 

Cobalt metal Nickel metal Tungsten carbide Borium carbide Titanium metal Tantal metal Niob metal Molybdenum Aluminum Cutting fluids Rubber materials Diamond... 

Other metals, such as chromium, manganese, nickel, tungsten, cobalt, and chromium, combine with iron to make steel, an alloy of superior strength, hardness, and durability. About 99% of all iron mined in the world today goes into the manufacture of steel. 

It is alloyed with iron, nickel and other metals to make Alnico, an alloy of unusual magnetic strength with many important uses. Stellite alloys, containing cobalt, chromium, and tungsten, are used for high-speed, heavy-duty, high temperature cutting tools, and for dies. 

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Density is a particularly important characteristic of alloys used in rotating machinery, because centrifugal stresses increase with density. Densities of the various metals in Table 1 range from 6.1 to 19.3 g/cm. Those of iron, nickel, and cobalt-base superaHoys fall in the range 7-8.5 g/cm. Those alloys which contain the heavier elements, ie, molybdenum, tantalum, or tungsten, have correspondingly high densities. 

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