| 摘要 |
<p>Ferromagnetic materials, e.g. Fe, Co, Ni or their alloys, or oxides, are mixed in a varnish base which is applied either to a sheet iron surface or a non-magnetic surface such as plastic, card or paper and then a shaped magnetic field applied to bring the varnish into the pattern desired. The initial application may be by brushing, spraying, printing or silk screen printing.</p> |
