Alloy rare-earth

Rare-earth alloys Rare-earth bromates... 

Figure 10 presents the Curie temperature (T ) vs the TM-content (x) for Co- and Fe-based biaary alloys. Alloying rare-earth elements with small amounts of transition metals (x < 0.2) leads to a decrease ia Curie temperature. This is particularly obvious ia the Gd—Co system where it corresponds to a nonmagnetic dilution similar to that of Cu (41,42). This iadicates that TM atoms experience no exchange coupling unless they are surrounded by a minimum number j of other TM atoms. The critical number is j = 5 for Fe and j = 7 for Co. The steep iacrease of for Co-based alloys with x about 0.7 is based on this effect. 

Aluminum and aluminum alloys Copper and copper alloys Rare-earth and rare-earth-like metals and alloys Low-melting metals and alloys Miscellaneous nonferrous metals and alloys Nickel and nickel alloys Precious metals and alloys Reactive and refractory metals and alloys... 

Magnetic properties of mechanically alloyed rare earth permanent magnet alloys... 

Study of liquid and membrane extraction processes is a matter of primary importance for intensive development of extraction, separation, and concentration methods of different nature substrates, especially such valuable ones as rare and scattered metals. They are used in metalluigy for production of special cast iron grades, steel, and nonferrous metals alloys. Rare earth metals (REM) additives increase quality of metalluigical products improve such properties as shock resistance, viscosity, and corrosion resistance. Such materials are used particularly in aerospace industry. A conventional extraction process of rare earth metals from such solutions comes down to chemical deposition with oxalic acid or ammonium carbonate, formation of oxalates or metals carbonates and further washing, filtration, and calcination to oxides that then are dissolved in hydrochloric acid and separated. - Researches that were carried out during the last years have demonstrated that liquid and membrane extraction processes are the most promising methods of extraction, concentration, and separation of rare and scattered metals ions." ... 

This review summarize various studies carried out on different generations of rare earth metal switchable mirrors based on polycrystalline, epitaxial layers, rare earth-Mg alloys, rare earth-... 

Gr. neos, new, and didymos, twin) In 1841, Mosander, extracted from cerite a new rose-colored oxide, which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals. 

Another sol—gel abrasive, produced by seeding with a-ferric oxide or its precursors, has been patented (30). A magnesium-modified version of this abrasive, also called Cubitron, is being produced as a replacement for the earlier type. Yttria [1314-36-91-vnc>A V eA sol—gel abrasives have also been patented (31), as well as rare earth oxide modified materials (32). These abrasives are all produced by 3M Corporation they have performed very well ia various applications such as ia coated abrasives for grinding stainless steel and exotic alloys. 

FeTi can also be modified with rare-earth metals, Ni, or Mn (15). AB alloys where A is a rare-earth metal or mischmetal, Ca, or Th, and B is Co or Ni have also been used. LaNi has shown special promise (16). 

Physical Properties. An overview of the metallurgy (qv) and soUd-state physics of the rare earths is available (6). The rare earths form aUoys with most metals. They can be present interstitiaUy, in soUd solutions, or as intermetaUic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and weU characteri2ed. AU impurity levels in the sample should be known. Some properties of the lanthanides are Usted in Table 3. 

Fused Salt Electrolysis. Only light RE metals (La to Nd) can be produced by molten salt electrolysis because these have a relatively low melting point compared to those of medium and heavy RE metals. Deposition of an alloy with another metal, Zn for example, is an alternative. The feed is a mixture of anhydrous RE chlorides and fluorides. The materials from which the electrolysis cell is constmcted are of great importance because of the high reactivity of the rare-earth metals. Molybdenum, tungsten, tantalum, or alternatively iron with ceramic or graphite linings are used as cmcible materials. Carbon is frequently used as an anode material. 

At the beginning of the twentieth century, the incandescent mantle, utilising the candoluminescence of a mixture of thorium (95% weight) and cerium oxides was developed. The pyrophoricity of rare-earth metals led to the invention of the lighter flint made through the alloying of iron and mischmetal. Since that time, numerous other appHcations have developed to coincide with the availabiUty of the rare-earth compounds on an industrial scale and having a controlled purity. 

Metallurgy. The strong affinity for oxygen and sulfur makes the rare-earth metals useflil in metallurgy (qv). Mischmetal acts as a trap for these Group 16 (VIA) elements, which are usually detrimental to the properties of steel (qv) or cast iron (qv). Resistance to high temperature oxidation and thermomechanical properties of several metals and alloys are thus significantly improved by the addition of small amounts of mischmetal or its siUcide (16,17). 

AHoy M16630 (ZE63A) which contains rare-earth metals and zinc, is designed to take advantage of a newer he at-treatment technique involving inward diffusion of hydrogen and formation of zirconium hydride [7704-99-6]. The alloy is heated in hydrogen at 480°C for 10, 24, or 72 hours for 6.3,... 

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