Cobalt-samarium

Cobalt, Samarium and Co/Sm alloys. Gomez et al. examined the electrodeposition of cobalt and samarium independently on vitreous carbon. Concomitant deposition of cobalt and samarium can also be achieved in the eutectic mixture of ChCI/Urea, forming either film or nanowire, depending on the temperature. " ... 

Cobalt-samarium magnets are used in high-efficiency motors. 

AHoys can be produced by the coreduction process, carried out at 1000°C with calcium, from the oxide mixture. For example, samarium oxide [12060-58-1] and cobalt oxide are coreduced to a SmCo [12017-68-4] powder, CaO then being removed. 

Nd2Fe B Family of Magnets and Related Materials. The high cost of cobalt and samarium stimulated investigation and development... 

Calciothermic reduction of samarium oxide, in the presence of cobalt powder, yields samarium-cobalt alloys in the powder form. The process is popularly known as reduction diffusion. Samarium oxide, mixed with cobalt powder and calcium hydride powder or calcium particles, is heated at 1200 °C under 1 atm hydrogen pressure to produce the alloys. Cobalt oxide sometimes partly replaces the cobalt metal in the charge for alloy preparation. This presents no difficulty because calcium can easily reduce cobalt oxide. A pelletized mixture of oxides of samarium and cobalt, cobalt and calcium, with the components taken in stoichiometric quantities, is heated at 1100-1200 °C in vacuum for 2 to 3 h. This process is called coreduction. In reduction diffusion as well as in coreduction, the metals samarium and/or cobalt form by reduction rather quickly but they need time to form the alloy by diffusion, which warrants holding the charge at the reaction temperature for 4 to 5 h. The yield of alloy in these processes ranges from 97 to 99%. Reduction diffusion is the method by which most of the 500 to 600 t of the magnetic samarium-cobalt alloy (SmCOs) are produced every year. 

The reduction diffusion process has also been used for the production of powders of the magnetic neodymium-iron-boron alloy (Nd15Fe77B8). The reaction involves use of a powder mix of neodymium oxide, iron, ferroboron and calcium. The reaction is conducted by heating the powder charge mixture at 1200 °C for 4 h under vacuum. Neodymium-iron-boron alloys are much more prone to oxidation than samarium-cobalt alloys and a proprietary leaching procedure is used for the separation of the alloy and calcium oxide. 

M Since the discovery of the magnetic properties of the cobalt alloy, samarium has been the "superstar" of the lanthanides. Music fans have their ears covered with samarium in the form of modem earphones... 

Table 11.5 Samarium-Cobalt composite (7 - US 2 - Ti02 3 - US + Ti02 4 - US +...

Single-phase perovskite MIECs such as Sr-doped lanthanum cobaltite (LSC), lanthanum ferrite (LSF), lanthanum cobalt ferrite (LSCF) and samarium cobaltite (SSC), and Ca-doped lanthanum ferrite (LCF) [13] are sometimes used alone in SOFC cathodes, as depicted in the lower right-hand comer of Figure 6.1, but combining an... 

Samarium (Sm), 74 631t, 634t electronic configuration, 1 41 At Samarium-cobalt magnets, 74 651 Sampatrilat, 5 159... 

The magnets utilized in these systems are typically neodymium-iron or samarium-cobalt disks with appropriately designed pole shoes that are placed with a variable air gap between them to accommodate an NMR probe designed to allow sample tubes (or flow probes) of 5 0 mm diameter. The magnet disks are typically wrapped along their sides with double wound wire to heat magnets to maintain a stable 35 °C operating... 

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. 

In the early 1970 s when samarium-cobalt magnets were first being proposed as a replacement for platinum-cobalt in microwave tubes, few could have anticipated the success that was to follow. Notwithstanding the traumas brought about by a quadrupling of cobalt prices, their use has grown steadily to the point where they now command a vitally important position in the permanent magnet market. 

Phosphor manufacture is still a dominant factor for suppliers of rare earth chemicals. According to industry sources (29), approximately 1/3 of the monetary volume of rare earth chemicals is used by the electronics industry. Included in this figure is Sm O for samarium-cobalt magnets. The remainder includes Gd O, La.,0 and Tb 0, for x-ray and lighting phosphors, and Y O ana... 

The production of samarium cobalt magnets requires lhe use of calcium. The reaction is... 

Samarium cobalt magnets have three to six times greater magnetic energy than alnicn magnets. 

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