Pickled High‑purity White Fused Alumina is produced by arc‑fusing high‑purity alumina powder, followed by pickling, magnetic separation and hydraulic classification processes. It features Al₂O₃ ≥99.2% with extremely low contents of iron, sodium and heavy‑metal impurities, which prevents black‑spot defects on alumina ceramic substrates. Strict particle‑size classification controls over‑sized particles, greatly reducing substrate scratching risks during wet grinding. With Mohs hardness of 9, it delivers stable cutting performance and is suitable for wet slurry grinding process on double‑side grinding machines.
| Processing Step | FEPA European Standard | W Series (National Standard Micro‑powder) | JIS Japanese Standard | Reference D50 μm | Process Description |
|---|---|---|---|---|---|
| Rough Grinding (remove cutting marks & large‑stock thinning) | F320 / F400 | W40 / W28 | 400#, 500# | 29‑17 | Rapidly remove cutting marks and flatten substrates for large material removal |
| Intermediate Grinding (correct parallelism & remove rough‑grinding damaged layer) | F600 / F800 | W20 / W14 | 600#, 800# | 9.3‑6.5 | Main‑stream mass‑production process; most electronic ceramic substrates are delivered after this step |
| Fine Grinding (reduce surface roughness for subsequent polishing / metallization) | F1000 / F1200 | W10 / W7 | 1000#, 1200# | 4.5‑3.0 |