18 декабря, 2015 
Pokraskin The coercive field strength of metallic iron pigments is primarily determined by their particle shape and size, and can be varied between 30 and 210 kA m-1. Pigments for analog music cassettes (Hc ~ 90 kA m-1) usually have a particle length of 0.35 pm (see Section 5.1.1, Table 5.1). The length to width ratio of the pigment needles is ca. 10 : 1. Finely divided pigments (particle length ca. 0.12 pm) with a coercive field strength of 130 kA m-1 are used for 8 mm video and digital audiocassettes (R-DAT), tapes used by television organizations (ED Beta, Betacam SP MP, M II, Digital Video D2), and for master videocassettes (mirror master tapes). In the field of data storage, a small quantity is used in micro floppy disks and backup cassettes.
Metallic pigments have a higher specific surface area (up to 60 m2 g-1) and a higher saturation magnetization than oxidic magnetic pigments. Their capacity for particle alignment corresponds to that of the oxides (see Table 5.1). Figure 5.2 shows the morphology of the metallic particles as TEM photographs.
5.1.4.3
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