Introduction
Silicon carbide ceramics (SiC) are advanced non-oxide ceramics valued for their hardness, thermal conductivity, and chemical stability. Available in grades like Black SiC and Green SiC, these materials provide a spectrum of properties for material science research. This article examines the key properties of silicon carbide ceramics, supported by a comparative table, to highlight their significance in research applications.
Quick answer: Silicon carbide ceramics are valued for hardness, wear resistance, thermal conductivity and chemical stability. For research use, grade, processing route, density, grain size and impurity control can matter as much as the base SiC composition.
Properties of Silicon Carbide Ceramics
Silicon carbide ceramics exhibit various properties that make them ideal for material science studies. Below are their key characteristics:
- High Hardness: Vickers hardness from 22.0 GPa (Black SiC) to 23.0 GPa (Green SiC), suitable for wear resistance studies.
- Thermal Conductivity: Ranges from 60 W/mK (Black SiC) to 200 W/mK (Green SiC), ideal for heat transfer research.
- Electrical Insulation: Volume resistivity up to >10¹⁸ ohm-cm (Green SiC), supporting electrical behavior studies.
- Chemical Stability: Negligible weight loss in acids (e.g., <0.00 mg/cm²/day in H₂SO₄ for Green SiC), perfect for corrosion studies.
- Low Thermal Expansion: CTE of 3.7 × 10⁻⁶/°C ensures dimensional stability under thermal stress.
Detailed Properties Table
The table below compares the properties of silicon carbide ceramics across Black SiC and Green SiC grades.
Property | Black SiC | Green SiC |
Main Characteristics | ||
Color | Black | Green |
Main Applications | Mechanical seals, corrosion-resistant parts | Mechanical seals, corrosion-resistant parts |
Characteristics | High hardness, wear resistance, corrosion resistance, and insulation | High hardness, wear resistance, corrosion resistance, and insulation |
Mechanical Properties | ||
Bulk Density (g/cm³) | 3.12 | 3.16 |
Water Absorption (%) | 0 | 0 |
Vickers Hardness (GPa) | 22.0 | 23.0 |
Flexural Strength (MPa) | 540 | 450 |
Young’s Modulus (GPa) | 430 | 440 |
Poisson’s Ratio | 0.16 | 0.17 |
Fracture Toughness (MPa m¹/²) | 4–5 | 2–3 |
Thermal Properties | ||
Thermal Conductivity (W/mK, 20°C) | 60 | 200 |
Specific Heat Capacity (J/(kg·K) × 10³) | 0.67 | 0.67 |
Thermal Shock Resistance (ΔT°C) | 400 | — |
Coefficient of Thermal Expansion (×10⁻⁶/°C, 40–400°C) | 3.7 | 3.7 |
Electrical Properties | ||
Volume Resistivity (ohm-cm, 20°C) | >10⁵ | >10¹⁸ |
Chemical Properties | ||
Nitric Acid (60%) Weight Loss (mg/cm²/day) | 0.04 | <0.00 |
Sulfuric Acid (95%) Weight Loss (mg/cm²/day) | 0.01 | <0.00 |
Caustic Soda (30%) Weight Loss (mg/cm²/day) | <0.00 | <0.00 |
Table Notes:
- Mechanical Properties: Black SiC’s higher fracture toughness (4–5 MPa m¹/²) offers insights into crack resistance.
- Thermal Properties: Green SiC’s higher thermal conductivity (200 W/mK) supports heat transfer studies.
- Chemical Stability: Green SiC’s superior corrosion resistance (<0.00 mg/cm²/day in acids) provides a benchmark for durability
Selection Notes and Related Materials
For SiC ceramic research, confirm grade, density, grain size, porosity, dimensions, tolerance, surface finish, thermal conductivity target and test environment. Related categories include Silicon Carbide (SiC) Ceramics, Silicon Nitride (Si3N4) Ceramics, Boron Carbide Ceramics (B4C) and Technical Ceramics.
FAQ
Why is silicon carbide useful in materials research? SiC combines high hardness, good thermal conductivity, chemical resistance and high-temperature stability, making it useful for wear, thermal, corrosion and structural studies.
What SiC specifications should be confirmed before ordering? Confirm grade, density, grain size or porosity, dimensions, tolerance, surface finish, thermal requirements, test environment, quantity and documentation needs.
Conclusion
Silicon carbide ceramics, with their diverse properties across Black SiC and Green SiC grades, are ideal for material science research. Their hardness, thermal conductivity, and chemical stability provide valuable insights into the effects of composition on ceramic performance.
Heeger Materials is a leading manufacturer and supplier of high-quality silicon carbide ceramic products in forms of plates, sheets, rods, tubes, crucibles, substrates, and customized parts, offering customized solutions for various industrial and research applications.