Niobium carbide (NbC) is a refractory ceramic material known for its high melting point, hardness, and excellent thermal and electrical conductivity. It finds applications in areas such as cutting tools, wear-resistant coatings, and high-temperature structural components. Here are some key parameters for niobium carbide:
- Chemical Formula: NbC
- Molecular Weight: Approximately 174.96 g/mol
- Crystal Structure: NbC has a cubic crystal structure, similar to other transition metal carbides, belonging to the NaCl-type (rock salt) structure.
- Density: Theoretical density of niobium carbide is around 8.53 g/cm³.
- Melting Point: The melting point of niobium carbide is very high, approximately 3830°C, making it suitable for extreme high-temperature applications.
- Hardness: NbC is characterized by a high Vickers hardness, typically ranging from 1800 to 2200 HV, which contributes to its wear-resistant properties.
- Thermal Conductivity: It exhibits good thermal conductivity, facilitating heat dissipation in high-temperature applications, although the exact value can vary depending on the purity and microstructure.
- Thermal Expansion Coefficient: The thermal expansion coefficient of niobium carbide is relatively low, enhancing its stability in varying temperature environments.
- Chemical Stability: NbC is highly resistant to corrosion from many acids and alkalis, except for hydrofluoric acid and hot concentrated alkalis.
- Electrical Conductivity: It is an electrical conductor, although its conductivity is lower than that of metallic niobium due to its ceramic nature.
- Synthesis: Niobium carbide is typically synthesized through carbothermal reduction of niobium oxide (Nb2O5) with carbon at elevated temperatures, often in a vacuum or controlled atmosphere to prevent contamination.
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Applications: NbC is used in the production of cemented carbide tools, wear-resistant coatings for machinery parts, as an additive in high-temperature ceramics, and in the nuclear industry due to its ability to absorb neutrons.
