Magnetic orientation of acicular iron particle in recording media

The orientation behavior of acicular iron particles in an applied field has been surveyed. A large orienting field is needed to align α-Fe particles. Dispersion degree and drying speed affect the particle alignment significantly when permanent magnets are used as orienting apparatus. To obtain high orientation of α-Fe metal tape, an orientation process was introduced. This process used both a repulsive magnet pair and an electromagnet to obtain the orienting field for the coated tape. The permanent magnet pair offers high orienting field above 5 kOe, and the latter offers a low residual orienting field during the drying process of the coating tape