Green silicon carbide (SiC) powder is a high-purity, synthetic abrasive material widely used in precision polishing applications, including optical fiber polishing. Its exceptional hardness (9.5 on the Mohs scale), sharp particle morphology, and chemical stability make it suitable for achieving ultra-smooth surfaces with minimal subsurface damage.
Key Properties for Optical Fiber Polishing:
High Purity (≥99%) – Minimizes contamination risks during polishing.
Controlled Particle Size (e.g., 0.5–10 µm) – Fine grades ensure smooth finishes without scratches.
Uniform Particle Shape – Sharp, angular grains enhance material removal rates while maintaining precision.
Chemical Inertness – Resists reactions with polishing slurries or fiber materials.
Applications in Optical Fiber Manufacturing:
Pre-Polishing Stages: Removes larger imperfections before final polishing.
Slurry Formulations: Mixed with water or oils for consistent polishing performance.
Core/Cladding Finishing: Helps achieve low surface roughness (<1 nm) for minimal signal loss.
Advantages Over Other Abrasives:
Harder than Alumina (Al₂O₃), but less aggressive than diamond, reducing risk of over-polishing.
More thermally conductive than silica, aiding heat dissipation during polishing.
Lower cost than diamond abrasives while still delivering high precision.
Recommended Grades for Fiber Polishing:
F800–F1200 (1–10 µm): For intermediate polishing.
F2000–F4000 (sub-micron): For ultra-fine finishing.
Considerations:
Slurry Concentration: Typically 5–20% SiC in water or glycol-based carriers.
Polishing Pressure & Speed: Optimized to prevent fiber brittleness or micro-cracks.
For critical final polishing, colloidal silica or cerium oxide may follow SiC steps to achieve atomic-level smoothness.