Neodymium alloys with

Calcium is generated in situ for effecting reduction in another process in which elemental sodium is introduced in the charge mixture. The production of neodymium metal or of its alloys by the reduction of neodymium sesquioxide with sodium in the presence of calcium chloride is known as the NEOCHEM process. This process was developed at the General Motors Research Laboratories in the 1980s. The overall reaction pertinent to the process can be written as... 

Misch metal is an alloy of about 50% cerium, 25% lanthanum, 15% neodymium and 10% other rare earth metals. Uses include manufacture of a pyrophoric alloy with iron and deoxidizer in metallurgical applications, getter for removal of oxygen from vacuum tubes, high strength magnesium alloys. 

I. N. Avertseva, M. V. Raevskaya, Hydrogen permeability and mechanical properties of palladium alloyed with ruthenium, samarium, yttrium, and neodymium, Phys. Met. Metall. 1994, 77(5), 518-521. 

Figure 2.16 shows the charge-discharge cycle characteristics of alloys in which part of the nickel component was replaced with cobalt. Misch metal (Mm), which is a mixture of rare earth elements such as lanthanum, cerium, praseodymium, and neodymium, was used in place of lanthanum. It was found that the partial replacement of nickel with cobalt and the substitution of the lanthanum content with Mm was very useful in improving the charge-discharge cycle life. However, such alloys have insufficient capacity, as shown in Figure 2.17 [18]. From study of the effect that their compositions had on the charge-discharge capacity, it was concluded that the best alloy elements were Mm(Ni-Co-Al-Mn)This alloy led to the commercialization of sealed nickel-M H batteries. All the battery manufacturers who use a rare earth-nickel-type alloy for the negative electrode material employ similar alloys with slightly different compositions.

Sihca is reduced to siUcon at 1300—1400°C by hydrogen, carbon, and a variety of metallic elements. Gaseous siUcon monoxide is also formed. At pressures of >40 MPa (400 atm), in the presence of aluminum and aluminum haUdes, siUca can be converted to silane in high yields by reaction with hydrogen (15). SiUcon itself is not hydrogenated under these conditions. The formation of siUcon by reduction of siUca with carbon is important in the technical preparation of the element and its alloys and in the preparation of siUcon carbide in the electric furnace. Reduction with lithium and sodium occurs at 200—250°C, with the formation of metal oxide and siUcate. At 800—900°C, siUca is reduced by calcium, magnesium, and aluminum. Other metals reported to reduce siUca to the element include manganese, iron, niobium, uranium, lanthanum, cerium, and neodymium (16). 

Figure 16 shows the charge-discharge cycle characteristics of alloys in which part of the nickel component was replaced with cobalt. Misch metal (Mm), which is a mixture of rare earth elements such as lanthanum, cerium, praseodymium, and neodymium, was used in place of lanthanum. It was found that the partial replacement of nickel with cobalt and the substi-... 

Several other useful modifications of calciothermic reduction have been successfully developed for the preparation of this neodymium-bearing magnetic alloy. One of these is reduction-extraction which involves the reduction of neodymium sesquioxide (Nd203) with calcium in a molten calcium chloride-sodium chloride salt bath at 750 °C and the simultaneous extraction of the reduced metal into a molten neodymium-zinc or neodymium-iron alloy pool. The neodymium-zinc alloy product is treated in vacuum to remove zinc and produce neodymium metal, while the neodymium-iron alloy is itself the end product of... 

Main uses. Calcium is important in steel production. It has a strong ability to alter the oxides and sulphides. Treatment with calcium modifies the melting points of inclusions which rapidly float out of the steel. Calcium is important in one method of producing a neodymium-iron alloy which is a neodymium ferro boron raw material (through, for instance, the reaction Nd203 + Ca + Fe — NdFe + byproducts). 

Important is the use of light rare earth elonents for production of hard magnetic materials. Most prominent are alloys of samarium with cobalt in the atomic ratio 1 5 or 2 17. It may also be assumed that in further development of these materials on a larger scale that praseodymium, neodymium, lanthanum and also individual heavy rare ecu h elements will be used to achieve particular effects. Interesting is the development of magnetic bubble memories based on gadolinium-galliiimrgarnets. 

Cerium is the principal metal in the alloy called misch metal. Misch metal is 50 percent cerium combined with lanthanum, neodymium, and a small amount of iron. Misch metal is used to make the flints for lighters. Cerium is often included in alloys of iron and other metals such as magnesium. A high-temperature alloy of three percent cerium with magnesium is used for jet engines. Some of cerium s compounds—for example, cerium(IV) oxide —are used to polish lenses, mirrors, and televi-... 

New permanent magnet materials, such as samarium-cobalt and, a fortiori, neodymium-iron-boron alloys, are also of special interest in the design of static devices with specific magnetic-field configurations. Apart from high remanence and coercive force values of magnets made of these materials, Chavanne et al. (1987) emphasize the presence of large anisotropy fields in the conception of these devices. 

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