Black silicon carbide (SiC) is commonly used in foam ceramics due to its excellent properties, such as high thermal conductivity, thermal shock resistance, mechanical strength, and chemical stability.
1. Foam Ceramic Filters for Metal Casting
Black SiC is used to produce open-cell foam ceramic filters for molten metal filtration (e.g., aluminum, iron, and steel casting).
It helps remove impurities (oxides, slag, inclusions) from molten metal, improving casting quality.
Its high thermal shock resistance prevents cracking when exposed to extreme temperature changes.
2. Porous Ceramic Structures
SiC foam ceramics are used in high-temperature insulation, catalyst supports, and gas diffusion layers.
The porous structure allows for efficient gas/liquid flow while maintaining structural integrity.
3. Refractory and Insulation Materials
Black SiC-based foam ceramics serve as lightweight refractory linings in furnaces and kilns.
They provide thermal insulation while withstanding harsh environments.
| TYPICAL CHEMICAL ANALYSIS | TYPICAL PHISICAL PROPERTIES | ||
| SiC | ≥98% | Hardness: | Mohs:9.15 |
| SiO2 | ≤1% | Melting Point: | Sublimes at 2250 ℃ |
| H2O3 | ≤0.5% | Maximum service temperature: | 1900℃ |
| Fe2O3 | ≤0.3% | Specific Gravity: | 3.2-3.45 g/cm3 |
| F.C | ≤0.3% | Bulk density(LPD): | 1.2-1.6 g/cm3 |
| Magnetic content | ≤0.02% | Color: | Black |
| Particle shape: | Hexagonal | ||
4. Advantages of Black SiC in Foam Ceramics
High strength & abrasion resistance – Maintains structure under stress.
Thermal shock resistance – Withstands rapid heating/cooling.
Chemical inertness – Resists corrosion from molten metals and gases.
Controlled porosity – Can be tailored for specific filtration needs.
5. Manufacturing Process
Replica method: A polymeric foam template is coated with a SiC slurry and then sintered.
Direct foaming: A SiC-based slurry is foamed and solidified before firing.
3D printing: Advanced techniques allow precise control over foam ceramic structures.
Conclusion
Black silicon carbide is a key material in foam ceramics, particularly for metal casting filters, high-temperature insulation, and porous structural components. Its durability and thermal properties make it ideal for demanding industrial applications.