White Fused Alumina Micropowder for Hardware & Mechanical Polishing
Main component: Fused α-Alumina, Al₂O₃ ≥99.2%. Mohs hardness 9.0. Low iron and low sodium content. It hardly causes blackening or staining on stainless steel/carbon steel hardware parts. Suitable for vibratory finishing, tumbling polishing, surface lapping, raw material for polishing paste & slurry, oilstone & grinding brick of stainless steel, mould steel, alloy steel, hardened steel, copper alloy and aluminum parts. Widely applied to valves, fasteners, kitchen hardware, precision mechanical components and pre-polishing of moulds.
✅ Core Advantages for Hardware Polishing
- Good self-sharpening performance. Particles fracture to continuously form new cutting edges for stable polishing efficiency without easy slipping.
- High purity and low Fe₂O₃. No rust spots or yellow stains easily left on stainless steel, better than brown fused alumina.
- Low heat generation during grinding to avoid workpiece burn.
- Complete particle size range (Chinese standard W-series micropowder, also available per FEPA/JIS mesh). Support progressive processes from rough polishing, medium polishing, fine polishing to pre-mirror finishing.
📌 Particle Size Selection for Hardware Polishing
| D50 Particle Size μm | Equivalent Mesh | Application for Hardware Polishing |
|---|---|---|
| 28~40 | 600# | Remove tool marks & coarse scratches, vibratory rough polishing |
| 20~28 | 800# | Medium polishing to eliminate coarse grinding lines |
| 14~20 | 1000# | Fine polishing to greatly reduce Ra value |
| 10~14 | 1200# | Pre-high-gloss polishing for mould & stainless steel parts |
| 7~10 | 1500# | Pre-mirror fine polishing |
| 5~7 | 2000# | High-precision hardware, raw material of polishing paste |
| 3~5 | 2500# | Ultra-fine lapping for low surface roughness |
Process recommendation: Gradually switch to finer grades, avoid large skip of particle sizes. Wet lapping (with water / lapping liquid) delivers better results and reduces scratches.
🧪 Standard Quality Indexes (Polishing Grade White Fused Alumina Micropowder)
- Al₂O₃ ≥99.2%
- Fe₂O₃ ≤0.04% (Iron control is critical for stainless steel polishing)
- Na₂O ≤0.30%
- Specific gravity: 3.95 g/cm³; Bulk density:1.75–1.95 g/cm³
- Oversized coarse particles strictly controlled (tight D90 limit to prevent heavy scratches)
- Particle shaping & magnetic iron removal, good dispersibility and low agglomeration
🛠 Common Application Processes
- Vibratory tumbler / barrel finishing machine: Micropowder + water + brightener for deburring and polishing bulk small hardware parts;
- Raw material for lapping compound / polishing wax: W10/W7/W5 micropowder for metal polishing paste;
- Surface lapping, flat grinding oilstone, PVA polishing wheel, nylon grinding head raw material;
- Lapping slurry: Mixed with water & additives for precision surface lapping of metals.
⚠️ Selection Notes
- Soft aluminum and pure copper: Use white fused alumina with caution, it tends to produce deep scratches. Finer grades or silica dioxide are alternatives.
- Final mirror finish: White fused alumina works for pre-polishing. Cerium oxide can be used for ultimate mirror effect.
- Export orders: COA particle size report available. Compliant with Chinese W / FEPA / JIS standards. English technical data sheet is available.