Importance and Interest of Intermetallic Compounds
Intermetallic compounds can present interesting properties for numerous applications.
Thermal properties:
The melting temperatures of many nitrides and carbides are around or above \({3000}{\rm \, °C}\) (see table below).
Compound | \(\ce{BN}\) | \(\ce{NbC}\) | \(\ce{TaN}\) | \(\ce{TaC}\) | \(\ce{TiN}\) | \(\ce{TiC}\) | \(\ce{VC}\) | \(\ce{WC}\) | \(\ce{ZrN}\) | \(\ce{ZrC}\) |
|---|---|---|---|---|---|---|---|---|---|---|
Fusion \(T\) \({\rm (°C)}\) | 3000 | 3500 | 3090 | 3800 | 2940 | 3150 | 2800 | 2750 | 2950 | 3500 |
Magnetic properties:
\(\ce{Fe3Al}\) and the analogous compounds \(\ce{Ni3Mn}\), \(\ce{MnCu2Al}\) are ferromagnetic. We can also mention intermetallic compounds in finely dispersed form in permanent magnet alloys like \(\ce{AlNiCo}\) ou \(\ce{PtCo}\).
Electronic properties:
semi-conductors such as covalent compounds III-V as \(\ce{InSb}\), \(\ce{GaAs}\) or II-VI as \(\ce{CdTe}\) and high critical temperature supraconductors such as \(\ce{Nb3Sn}\), \(\ce{V3Si}\) or \(\ce{Nb3AlGe}\).
Mechanical properties:
Intermetallic compounds in the form of precipitates or finely dispersed particles within a metal solid solution can give the material very interesting mechanical properties. Numerous industrial materials are strengthened by precipitation: carbides (specialty steels), intermetallic compounds (light alloys, refractory alloys, high-performance steels).
In addition, the hardness and refractory nature of the carbides lead to their use in the form of sintered parts for some applications (for example, cutting tools).