Neodymium magnet

Fig. 53.1. Details of magnetic graphite-epoxy composite electrode with incorporated magnet, (a) Conducting graphite-epoxy composite (b) copper disc facilitating electrical contact between the composite material and copper wire (c) leading to the electrochemical workstation (d) plastic sleeve (e) permanent neodymium magnet. With permission from Ref. [1].

Incorporate the neodymium magnet into the body of the paste of graphite-epoxy composite, 2 mm under the surface of the electrode [1] and continue placing the paste until filling all the cavity. Cure the conducting composite at 40°C during 1 week. Once the resin is hardened, polish the surface first with abrasive paper and then with alumina paper. 

Place the resulting paste into the body of the electrode prepared as described in Subheading 3.1.1, where a neodymium magnet (diameter 3 mm, height 1.5 mm, Halde Gac Sdad, Spain, catalog number N35D315) has been introduced 2 mm under the surface of the electrode. 

Headphones Neodymium magnets can be used in stereo headphones because they are powerful and lightweight. Write the electron configuration for neodymium. In which block of the periodic table is it ... 

Following are listed applications of neodymium magnets (Brown et al. 2002). 

A well-known method to increase the coercivity in Nd-Fe-B magnets is to substitute the heavy rare-earth (HREE) elements like Dysprosium (Dy) and Terbium (Tb) for Nd (Dhakal et al. 2014 Hirosawa et al. 1986 Hirota et al. 2006). Substitution with dysprosium also raises the Curie-point for these magnets, so that they can be used at higher temperatures. The amount of dysprosium in neodymium magnets may vary from 0.8 to 1.2 % (NdFeB-info.com 2015). 

Owing to peculiar physical and chemical properties, rare-earth elements are used in various materials and consumer products, and thus, have become indispensable for our modem life. The world-wide rare-earth oxide consumption by the market sector in 2008 (Goonan, 2011) shown in Fig. 1 indicates that rare earths are used in glass industry, catalysts, neodymium magnets, battery alloys and other metallurgical additives, phosphors, ceramics, and other. According to the world mine production of rare earth in 2009 (Cordier, 2011),... 

FIGURE 4 General flow sheet for in-plant recycling of neodymium magnet scrap (Machida, 2004 Takeda, 2000). 

Koyama and Tanaka examined the oxidative roasting—selective leaching—solvent extraction process of the scrap neodymium magnet (Koyama and Tanaka, 2009, 2011a Koyama et al., 2009 Tanaka et al., 2009). When 1000 kg of scrap magnet (Nd2Fci4B) is dissolved by mineral acid, its required amount is calculated on the basis of the following reactions ... 

TABLE 4 Percentages of Neodymium, Dysprosium, and Iron Leached from Neodymium Magnet After Oxidative Roasting (Koyama and Tanaka, 2011a) ... 

Miura, K., 2011. Demagnetization of neodymium magnets at room temperature. In Lecture in Tokyo on November 11, 2011 Japan Society of Material Cycles and Waste Management (Abstract available at http //jsmcwm.or.jp/jimu/event 0111111-youshi.pdf, Accessed tm December 15, 2011). 

Wolber T, Ryf S, Binggeli C, Holzmeister J, Brunkhorst C, Luechinger R, Duru F. Potential interference of small neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators. Heart Rhythm 2007 4 1-4. 

Boron has an increasing use in high technology in connection with the introduction of the iron-boron-neodymium magnet. This has been treated in the neodymium section in Chapter 17 Rare Earth Metals. 

The electrical and hybrid vehicles are becoming a serious alternative to the internal combustion engine. But hybrid green cars would not exist without special materials like rare earth elements -lanthanum for their batteries, neodymium magnets for their electric motors, advanced piezoelectric materials for their engines, and various polymers and plastics for automotive appliances. For example, the battery in a single Toyota Prius contains more than 20 pounds of the rare earth element lanthanum. 

---