Study of doped higher manganese silicides crystals by transmission electron diffraction and electron backscatter diffraction

• Published in: Crystallography reports Vol. 59; no. 1; pp. 78 - 87
• Main Authors: Orekhov, A. S., Suvorova, E. I.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 2014
• Subjects: Crystallography and Scattering Methods; Physics; Physics and Astronomy; Real Structure of Crystals; Crystallography Report; Transmission Electron Diffraction; Scanning Electron Micro Image; High Manganese Silicide; Molybdenum Disilicide
• ISSN: 1063-7745; 1562-689X
• DOI: 10.1134/S106377451401009X

The microstructure of Al-, Ge-, and Mo-doped higher manganese silicide crystals (HMS), grown by the Bridgman method have been investigated by transmission electron diffraction, electron backscatter diffraction, scanning electron microscopy, and X-ray energy-dispersive spectrometry. It is shown that the matrix crystal has the Mn 4 Si 7 structure. The introduction of Ge and Mo impurities into an HMS crystal results in the precipitation of Si-Ge solid solution and molybdenum disilicide. The size of precipitates varies in a wide range: from several nanometers to several hundreds of micrometers. The following orientation relationships between Ge-Si precipitates and the Mn 4 Si 7 crystal were determined: (112) Ge-Si ‖ (010)[100] Mn 4 Si 7 . Polycrystalline MoSi 2 precipitates form a multicomponent texture along the [001] Mn 4 Si 7 direction. Small amounts of cubic MnSi and Al-Mn-Si alloy precipitates were revealed. In addition, Al oxide was observed mainly in crystal pores. It is shown that 0.5–0.8 at % Al, 0.4–0.6 at % Mo, and 1.5–2.0 at % Ge impurities are incorporated into the Mn 4 Si 7 lattice.