Home / News & Blog / Abrasive Blog / Black Silicon Carbide: B2B Technical Sourcing & Application Guide
Black Silicon Carbide (Black SiC) is a high-performance synthetic abrasive material produced through high-temperature carbothermal reduction of quartz sand and petroleum coke. With excellent hardness, thermal conductivity, chemical stability, and self-sharpening properties, it is widely used in abrasive tools, refractory materials, metallurgical applications, and precision processing industries. Thanks to its outstanding cutting efficiency, thermal shock resistance, and cost-effectiveness, Black SiC has become a preferred choice for grinding and processing non-ferrous metals, cast iron, glass, ceramics, stone, and other hard materials.
Black Silicon Carbide (Black SiC) is a synthetic non-metallic mineral manufactured through the high-temperature carbothermal reduction of high-purity quartz sand (SiO2) and petroleum coke in an electric resistance furnace at temperatures exceeding 2200°C. Characterized by its hexagonal crystal structure, dark metallic luster, extreme hardness, and excellent thermal conductivity, Black SiC serves as an essential raw material for global abrasive, refractory, metallurgical, and electronics industries.
To meet stringent international sourcing standards, high-grade Black Silicon Carbide is categorized based on SiC chemical purity and physical consistency.
|
Parameter / Specification |
Grade A (High Purity) |
Grade B (Standard) |
Industrial Relevance |
|
SiC Content (Min.) |
98.50% |
95.00% – 97.50% |
Determines hardness, thermal stability, and refractory limits. |
|
Free Carbon (FC Max.) |
0.25% |
0.45% |
Lower FC prevents oxidation and thermal shock failure. |
|
Free Iron ($\text{Fe}_2\text{O}_3$ Max.) |
0.15% |
0.30% |
Critical for electrical insulation and avoiding surface staining. |
|
Mohs Hardness |
9.2 – 9.5 |
9.2 |
Second only to Diamond and CBN; high cutting efficiency. |
|
Knoop Hardness |
2800 – 3300 kg/mm² |
2800 kg/mm² |
Measures resistance to localized micro-indentation. |
|
Bulk Density |
1.40 – 1.58 g/cm³ |
1.35 – 1.50 g/cm³ |
Influences porosity and packing density in abrasive wheels. |
|
Max Working Temp. |
1900°C (Inert) / 1600°C (Air) |
1500°C (Air) |
High thermal resistance for kiln furniture and refractories. |
We supply Black Silicon Carbide tailored to major international grading systems:
Macro Grits (FEPA F12 to F220 / JIS #12 to #240): Ideal for vitrified/resinoid bonded grinding wheels, heavy-duty cutting discs, and sandblasting nozzles.
Micro Powders (FEPA F230 to F2000 / JIS #240 to #3000 / GB W63 to W1.5): Precision-graded via hydraulic sedimentation or air classification for semiconductor lapping and optical glass polishing.
Refractory Section Sand & Fine Powders (0-1mm, 1-3mm, 3-5mm, -200 Mesh, -325 Mesh): Specially sized for castables, ramming mixes, shaped SiC bricks, and metallurgical deoxidizers.
Black SiC features extreme sharpness and excellent self-sharpening properties. It is widely used in ceramic grinding wheels, resinoid cutoff wheels, waterproof sandpapers, and abrasive belts. Ideal for grinding materials with low tensile strength, such as gray cast iron, non-ferrous metals (brass, aluminum), glass, stone, marble, rubber, and leather.
Due to its high thermal conductivity (60–120 W/(m·K)) and low coefficient of thermal expansion, Black SiC resists severe thermal shock and slag corrosion. Key products include kiln shelves, saggers, muffles, blast furnace linings, and monolithic refractory castables.
In iron foundries and steelmaking plants, metallurgical grade SiC (80%-90% SiC) acts as a powerful deoxidizing agent, improving molten iron fluid flow, promoting graphite nucleation, and replacing expensive ferrosilicon.
Acid-washed and water-washed micro powders are engineered with tight particle size distribution (PSD) for wire sawing silicon wafers, quartz crystals, hard alloys, and ceramic components.
|
Feature |
Black Silicon Carbide |
Green Silicon Carbide |
Brown Fused Alumina (BFA) |
|
Main Composition |
SiC ≥ 98.0% |
SiC ≥ 99.0% |
SiC ≥ 95.0% |
|
Hardness (Mohs) |
9.2 – 9.3 |
9.4 – 9.5 |
9.0 |
|
Friability / Toughness |
Friable, high self-sharpening |
Very friable, brittle |
High toughness, impact-resistant |
|
Primary Target Workpiece |
Cast Iron, Glass, Stone, Copper |
Carbide Tools, Titanium, Quartz |
Carbon Steel, Stainless Steel, Wood |
|
Price Point |
Moderate (Cost-effective) |
Premium / High |
Economical |
Q1: What is the main difference between Black Silicon Carbide and Green Silicon Carbide?
Green SiC is produced using high-purity silica sand with salt added as a reaction agent during smelting, resulting in higher purity (≥ 99%) and higher hardness, but increased brittleness and cost. Black SiC (≥ 98% purity) offers slightly higher toughness, superior cost-efficiency, and is ideal for cast iron, non-ferrous metals, stone, and refractories.
Q2: Why is Black Silicon Carbide generally not recommended for grinding steel components?
At high grinding temperatures, Silicon Carbide reacts chemically with iron to form iron silicides, leading to rapid chemical wear of the abrasive grains. For high-tensile steels and stainless steels, Brown Fused Alumina (BFA) or White Fused Alumina (WFA) is recommended.
Q3: Which sizing standards are supported for Black SiC Micro Powder?
We support international FEPA standards (F230 to F2000), JIS standards (#240 to #3000), and GB standards (W63 to W0.5/W1.5). Custom particle size distributions (PSD) can also be tailored to specific semiconductor lapping or optical polishing requirements.
