Advantages of Black SiC Micropowder
Black silicon carbide micropowder (α-SiC, SiC ≥98.5%) is hexagonal black crystalline fine powder (0.5–60 μm). Compared with green SiC, fused alumina and other abrasives, it has comprehensive superior properties:
–Excellent Mechanical Abrasive Performance
- Ultra-high hardness: Mohs hardness 9.15–9.2, sharper cutting edges than white/brown fused alumina, fast stock removal.
- High toughness & good self-sharpening: Higher toughness than green SiC. During grinding, dull particle edges crack naturally to form new sharp cutting points, maintaining stable polishing efficiency without frequent tool replacement.
- Super wear resistance: Service life 5–20× longer than cast iron lining materials when used as wear filler.
–Outstanding Thermal Properties
- Extreme heat resistance: Decomposes above 2250°C, long-term stable at 1900°C; excellent thermal shock resistance, no cracking under rapid temperature swings.
- High thermal conductivity: Far better than alumina, accelerates heat dissipation during high-speed grinding, avoids workpiece thermal burn; ideal for high-temperature thermal conductive components.
- Low thermal expansion coefficient: Minimal dimensional deformation under high temperature, guarantees precision for high-temp ceramic & sealing parts.
–Superior Chemical Stability
- Complete acid & alkali corrosion resistance at room temperature; inert to most molten metals, no chemical reaction during metal grinding/melting.
- Low impurity grade (Fe₂O₃ ≤0.2%, free carbon ≤0.2%): avoids iron contamination for optical, semiconductor and high-purity refractory products.
–Extra Functional Merits
- Weak semiconductor conductivity, adjustable resistance for anti-static filler applications.
- Cost-effective raw material: lower production cost than green SiC, suitable for mass industrial grinding of low-tensile-strength materials.
- High filling compatibility: evenly dispersed in resin, rubber, glaze and metal matrix composite.
Main Industrial Applications
–Abrasive, Lapping & Polishing
Black SiC micropowder is the primary fine abrasive for low-tensile-strength materials (glass, stone, cast iron, non-ferrous metal):
- Bonded abrasives: Raw material for resin grinding wheels, oil stones, grinding heads, whetstones for cast iron, aluminum, copper, marble and ceramic cutting/grinding.
- Coated abrasives: Sandpaper, abrasive cloth for wood, paint, metal surface fine sanding.
- Polishing supplies: Polishing paste, polishing fluid, diamond polishing wax for jade, gemstone, optical glass, ceramic tile mirror finishing.
- Precision lapping: Wafer rough grinding for photovoltaic monocrystalline/polycrystalline silicon; cylinder liner honing, mold super-finishing, metallographic specimen polishing.
- Abrasive blasting media: Fine blasting powder for derusting, deburring and matte surface treatment of aluminum alloy, cast iron workpieces.
–Advanced Refractories & High-Temperature Kiln Materials
- Raw material for recrystallized SiC refractory, silicon nitride bonded SiC parts, blast furnace lining, high-temperature kiln furniture, saggar and roller sticks.
- Steelmaking deoxidizer: replaces silicon powder for furnace deoxidation, shortens smelting time, improves steel purity and energy efficiency.
- SiC heating element (silicon carbon rod) production filler.
–High-Performance Functional Ceramics
- Sintered SiC structural ceramics: Mechanical sealing rings for oil & chemical pumps, wear-resistant nozzles, turbine blades, high-temperature bearing sleeves (lightweight, corrosion-resistant, long service life).
- Automotive honeycomb ceramic carrier for exhaust gas purification; ceramic filter plates.
- Wear-resistant ceramic tiles, ceramic glaze additive to boost surface hardness and scratch resistance.
–Wear-Resistant Composite Fillers
- Rubber & plastic filler: Added to rubber rollers, brake linings, wear-resistant floor coatings to enhance friction and abrasion resistance.
- Anti-corrosion wear-resistant coating: Sprayed on water turbine impellers, pump casings, pipeline liners, mining hoppers; extends service life by 1–2 times.
- Wear-resistant epoxy floor, industrial anti-slip padding additive.
–Other Emerging & Special Fields
- Semiconductor & electronics: Substrate thermal conductive filler, heat dissipation composite powder for power devices.
- Composite reinforcement: Filler for metal matrix composites to improve hardness and heat conductivity.
- Foundry: Anti-stick coating for casting molds, high-temperature crucible raw material.
3. Brief Comparison Tip vs Green SiC Micropowder
- Black SiC: Higher toughness, lower cost, for glass, stone, cast iron, general polishing & refractories.
- Green SiC: Higher purity, sharper self-sharpening, for hard alloy, optical lens, ultra-precision mold finishing.
| Item | Black Silicon Carbide Micropowder | Green Silicon Carbide Micropowder |
|---|---|---|
| Main Purity | SiC ≥ 97%–98.5% | SiC ≥ 99% |
| Hardness | High (Mohs 9.15) | Higher (Mohs 9.2–9.3) |
| Toughness | Higher toughness | Brittle, sharper but less tough |
| Self‑sharpening | Good | Excellent |
| Typical Use | Cast iron, glass, stone, non‑ferrous metals, refractories, general polishing, blasting | Carbide tools, precision optics, semiconductor wafers, ultra‑fine finishing |
| Cost | Lower | Higher |
| Surface Finish | Matte to fine polish | Ultra‑precision finish |