This presentation is about Cr3Si intermetallics. Its uses, structure and properties.

1. Cr-Si Intermetallics
Presented by:
Sayan Baidya
12407EN014

2. Cr-Si Phase Diagram

3. Intermetallics in system
The binary Cr-Si system consists of four Intermetallics:
 CrSi
 Cr₃Si
 CrSi₂
 Cr₅Si₃

4. Structure and Properties of Cr₃Si
 Phase Label: Cr3Si
 Structure Class: Frank-Kasper (FK) phases
 The most common members of a FK-phases family are: A15, Laves phases,
σ, μ, M, P, and R.
 A15 phase (also known as β-W)
 The Si atoms occupy the BCC positions of the lattice and there are 2 Cr atoms in
each face. The Planes containing the Cr atoms in x,y and z directions are
mutually perpendicular to each other. When connected, it forms a Icosahedron.
 Classification by Properties: Pauli paramagnet, metal
 Pearson Symbol: cP8
 Lattice Type: P
 Density: ρ = 6460 Kg·m−3

5.  (Cr pink, Si blue)

6. Unit Cell Parameters
a [Å] b [Å] c [Å] α [deg] β [deg] γ [deg]
4.5550 4.5550 4.5550 90.000 90.000 90.000
Fractional Coordinates of Atoms in the Asymmetric Unit
Site Label Element x y z
Cr Cr 0.2500 0.0000 0.5000
Si Si 0.0000 0.0000 0.0000

7. Other intermetallics with similar structure
 Vanadium-silicon
 Vanadium-gallium
 Niobium-germanium
 Niobium-tin
Application:
 These compounds have superconductivity at around 20 K (−253 °C), which is
comparatively high, and remain superconductive in magnetic fields of tens of
teslas.
 They are used for some high field applications, for example high-end MRI
scanners and NMR spectrometers.

8. Structure and Properties of CrSi₂
 Prototype: CrSi2
 Pearson Symbol: hP9
 Structure Class : C40
 Other compounds with this structure: Ge2Ta, Ge2V, HfSn2, Ge2Nb, MoSi2, Si2Ta,
Si2V, Si2W

9. Lattice structure of CrSi2
Cr atoms : Green
Si atoms: white

10. References
 http://materials.springer.com/isp/crystallographic/docs/sd_0532970
 http://som.web.cmu.edu/structures2/S029-Cr3Si.html
 https://homepage.univie.ac.at/michael.leitner/lattice/