Can Platelet Alumina be used as abrasive filler for sapphire substrate polishing pad?
Answer: Yes. Platelet alumina (plate-shaped α‑Al₂O₃) is suitable as grinding filler for fixed-abrasive polishing pads for sapphire substrates, mainly applied in rough and intermediate polishing stages. Since sapphire is single-crystal α‑alumina, platelet alumina is the same material system and avoids foreign contamination.
Advantages
- Sliding polishing mechanism Flat hexagonal platelet particles tend to align parallel to sapphire surface under pressure. It performs surface-contact sliding micro-cutting instead of sharp-edge scratching. Compared with fused white alumina, it greatly reduces deep scratches and subsurface damage, improving LED epitaxy yield.
- Matched hardness Mohs hardness 9, matching sapphire. It efficiently removes subsurface damage after slicing and lapping. Silica alone gives too low removal rate.
- High purity requirement High-purity α-phase platelet alumina (Al₂O₃ ≥99.9%, low Fe, Na, Si) is required to prevent metal ion contamination on sapphire surface, which affects LED performance.
