Abstract
As a means for improving the iron loss in grain oriented silicon steel sheets, a TiN ceramic film was formed by a CVD method on the polished silicon steel sheet. The following results were obtained.
(1) The TiN ceramic film moderately increased the magnetic flux density B8 (T) of the silicon steel sheet by 0.009-0.012 T, while the iron loss W17⁄50 (W/kg) was dramatically improved by 0.11-0.23 W/kg. This improvement in iron loss is more marked in silicon steel sheet with a higher magnetic flux density. For example, a silicon steel sheet with B8=1.93 T and W17⁄50=0.89 W/kg after magnetic domain refinements manifested an ultra-low iron loss of 0.57 W/kg, which represents to a 36% improvement in iron loss.
(2) The difference in iron loss when the TiN film was formed on a polished silicon steel sheet by the thermal CVD method was 0.01-0.03 W/kg greater than that when plasma CVD was used.
(3) In a comparison of the results of the CVD and PVD methods, a similar difference was obtained with the PVD method (HCD), which produced an iron loss 0.01-0.05 W/kg greater than that with the CVD method.
(4) No appreciable difference among TiN silicon steel sheets was apparent in magnetostriction or magnetic domains, and it is suspected that these differences in the improvement of iron loss (ΔW) were due to the coating conditions used for CVD or PVD, or to a slight difference in the properties of the TiN film by each method.
