Abstract
The surface and bulk microstructure of Mn-Zn ferrite single crystals oxidized at 0.7% ρo 2 have been investigated using SEM and TEM methods, assisted by energy- dispersive X-ray micro analysis. In samples heat-treated at 1000° C, haematite formed as an irregular surface layer and as laths which grew throughout the bulk, parallel with the {1 1 1 }⌈ planes (where F = ferrite). The haematite laths were related epitaxially to the ferrite host through the relationships (0001)H | {1 1 1 }F (where H = haematite) and $$\langle \bar 1010\rangle _H ||\langle \bar 110\rangle _F $$ . However, it was found that the latter parallelism was not exact because the haematite and ferrite lattices were rotated by 1.1 ± 0.2° about the axis perpendicular to the interface between them (i.e. [0001]H, F). The sites for the nucleation of haematite second phase were also observed in highly oxidized ferrite. The formation of small planar defects (< O.1 μm in length) in the ferrite, lying parallel to {1 10} planes, is interpreted as the combination of a local shear with the ordering of cation vacancies resulting from the oxidation. Small volumes of other second phases were also recognized, by virtue of both compositional and microstructural differences from the host ferrite.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call