日本金属学会誌

J. Japan Inst. Metals, Vol. 60, No. 8 (1996),
pp. 781-786

TEM Observation of Near-Surface of Silicon Steel SheetDomain-refined by TiN Coating

Yukio Inokuti

Research Laboratories, Kawasaki Steel Corp., 1, Kawasaki-cho, Chuo-ku, Chiba 260

Abstract:

In order to clarify the mechanism responsible for the ultra-low iron loss of TiN-coated grain oriented silicon steel sheet, the structure of TiN films and steel sheet in the vicinity of the near-surface of the (011)[100] single crystal of silicon steel was observed by transmission electron microscope (TEM). The sample for observation of TEM was taken initially by mechanical processing from a marked domain-refined area of the TiN-coated silicon steel sheet, and finally thinned by using the focused ion beam (FIB) technique.
Diffraction patterns of TiN films and silicon steel sheet were satisfactory, showing (110)TiN//(100)Si-steel, [111]TiN//[011]Si-steel. The degree of coherency between [111]TiN and [011]Si-steel showed a good value of 4.5%. An intermixed layer of TiN and silicon steel about 10 nm in width with fine transverse fringes was also observed.

It should be emphasized that the ultra-low iron loss in the TiN-coated silicon steel sheet obtained by inducing radical domain refinement can be achieved by good coherency between the TiN films and single crystal of silicon steel with (011)[100], namely, the Goss orientation, in which the difference of the thermal expansion coefficients of the ceramic TiN films and silicon steel sheet, after cooling from 973 K plasma coating to room temperature, strongly tensions the near-surface of the TiN-coated silicon steel sheet to the [100]Si-steel direction (elastic strain along one axis).


(Received April 1, 1996)

Keywords:

grain oriented silicon steel, TiN film, domain refinement, coherency, (111)[110], (011)[100], single crystal, adhesion, near-surface


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