Abstract
An improvement in the iron loss in grain oriented silicon steel sheet was investigated for TiN ceramic coating produced by ion plating on polished silicon steel sheets. The influence of the coating conditions on magnetic properties was also investigated, relating to the thickness, bias voltage, coating temperature, tension, vacuum pressure and reactive N2 gas used for TiN ceramic coating by the hollow cathode discharge (HCD) method.
The experimental results obtained are summarized as follows.
(1) The magnetic flux density B8(T) of silicon steel sheets with a thin TiN film increases moderately to 0.0040.015T, while the iron loss W17/50 (W/kg) is improved dramatically to 0.11-0.23W/kg.
(2) The iron loss in the TiN-coated silicon steel sheet by the HCD method is most improved under the coating conditions of (a) the thickness above 0.7μm, (b) bias voltages in the range of-50 to-100V, (c) coating temperatures in the range of 573 to 673K, (d) tensions in the range of 0.9 to 5MPa, (e) vacuum pressures above 0.3Pa, and (f) reactive N2 gas above 150SCCM.
(3) The domain structure of the chemically polished and TiN-coated areas inside a single giant secondary Goss grain changed drastically, showing four to six narrow wall spacings from an original 180° main domain with large black and white wall spacings elongated in the rolling direction.
