Magnetic iron oxide

Magnetic - from a place called Magnesia where magnetic iron oxide (Magnetite) occurred naturally. 

Mag netic Tapes. Chromium dioxide, Cr02, is used as a ferromagnetic material in high fidelity magnetic tapes (qv). Chromium dioxide has several technical advantages over the magnetic iron oxides generally used (58,246). 

Eisenoxydul-hydrat, n. ferrous hydroxide, iron(ll) hydroxide, -oxyd, n. ferrosoferric oxide, iron(II,III) oxide, magnetic iron oxide (FeaOi). -salz, n. ferrous salt, iron(II) salt, -sulfat, n. ferrous sulfate, iron(II) sulfate, -verbindung, /. ferrous compound, iron(ll) compound. 

Magnetic iron oxide nanoparticles synthesis, stabilization, vectorization, physicochemical characterizations, and biological applications. Chemical Reviews, 108 (6), 2064-2110. 

Laurent, S., Bridot, J.L., Elst, L.V. and Muller, R.N. (2010) Magnetic iron oxide nanopartides for biomedical applications. Future Medicinal Chemistry, 2 (3), 427 149. 

Tan, Y.W., Zhuang, Z.B., Peng, Q. and Li, Y.D. (2008) Room-temperature soft magnetic iron oxide nanocrystals ... 

P. Calvert and A. Broad, Biomimetic routes to magnetic iron oxide-polymer composites. In K.L. Mittal (Ed.), Polymers in Information Storage Technology, Plenum Press, New York, 1991, p. 257. 

Magnetic (iron oxide core) microspheres have been imprinted with S-pro-pranolol. The magnetism allowed the facile separation of the imprinted beads from the liquid matrix. The particles exhibited the expected affinity towards the template molecule. This technique was also proposed as a putative tool for cell sorting [81]. 

Graft polymerization of monomers such as acrylic acid on core particles consisting of magnetic iron oxide embedded in cross-linked poly (vinyl alcohol) (PVA) has been described previously (2). 

Brain JD, Bloom SD, Valberg PA, Gehr P (1984) Correlation between the behavior of magnetic iron oxide particles in the lungs of rabbits and phagocytosis. Exp Lung Res 6 115-131. 

Mixed metal oxide pigments containing iron oxide are also used (see Section 3.1.3). Magnetic iron oxide pigments are discussed in Sections 5.1.1 and 5.1.2. Transparent iron oxide pigments are described in Section 5.4.1. Methods of analysis and specifications of iron oxide pigments are listed in the standards given in Table 1. 

The saturation magnetization Ms is a specific constant for the material and for magnetic iron oxides is principally determined by the Fe2 + ion content. The ratio of remanent magnetization to saturation magnetization (Mr/Ms) for the tape depends mainly on the orientation of the pigment needles with respect to the longitudinal direction of the tape, and should approach the theoretical maximum value of unity as closely as possible. 

Producers of magnetic iron oxides include BASF and Bayer (Germany) Ishihara, Sakai, Titan K., and Toda K (Japan) 3 M, Mitsui, Magnox, and ISK Magnetics (USA) Saehan Media (Korea) and Herdilla (India). 

World production of cobalt-free magnetic iron oxides in 1995 was ca. 13 000 t, of which ca. 96% was used in compact cassettes and audio tapes, and ca. 4% in computer tapes. 

Cobalt-containing pigments are mainly produced by the magnetic iron oxide producers listed in Section 5.1.1. World production for 1995 was 40000 t, of which the highest proportion (ca. 85 %) was used for video tapes. 

Production. Metallic iron pigments are commercially produced by the reduction of acicular (needle-shaped) iron compounds [5.30], As in the production of magnetic iron oxide pigments, the starting materials are iron oxide hydroxides (see Section 3.1.1) or iron oxalates, which are reduced to iron in a stream of hydrogen either directly or via oxidic intermediates. 

Laboratory analysis of flush water indicates that some non-magnetic iron oxide may also be retained by the EMF. The non-magnctic iron removal is believed to be due to the presence of magnetic/noii-magnetic composite particles, which are magnetically attracted by the filter. 

The water was then replaced with methanol. This was accomplished by aspirating 800 ml of 0.2 M NaCI and bringing the total volume to 1 L with methanol. The material was resuspended, and magnetically extracted 800 ml of supernatant were removed, and another 800 ml of methanol were added. After three additions of methanol, the oxide was ready for silanization in a solution which was approximately 1% (V/V) water. A portion of the precipitate was dried at 70°C for 24 hours and weighed 11.2 g of magnetic iron oxide were formed. 

Polymer-inorganic composites with 25 mol% Fe on a cation basis were prepared using a sol of GLYMO and Al(OsBu)3 mixed with a solution of the structure-directing PI-/7-PEO diblock copolymer (see Table 21.1, F and G) and iron(m) ethoxide powder. For the production of a crystalline magnetic iron-oxide phase, the as-made composites were calcined at elevated temperatures in air. SAXS and TEM were performed to determine the structure and order in the materials. Figure 21.17a shows SAXS data for the pure diblock copolymer (1), the as-made polymer-inorganic composite (2), and material calcined to 750°C (3). 

If both substrates to be bonded are nonconducting, then the adhesive formulation must contain a susceptor material. Susceptors can have a small percentage of magnetic iron oxide, iron filings, or carbon additives. A susceptor can also be a steel screen or perforated steel foil that is embedded in the adhesive bond line. It has been found that graphite fiber composites used in the automotive and aerospace industries are sufficiently conductive that they can be successfully heated with induction. Design considerations must be taken into account in placement of the graphite reinforcement, so that the material heats uniformly. 

Magnetic iron oxide, Fe304, occurs naturally as the mineral magnetite. It has an inverse spinel structure (see Chapter 9) because it contains Fe2+ and Fe3+, and the formula can be written as FeO Fe203. 

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