White aluminum oxide (white fused alumina) is a high-purity, sharp, friable blasting abrasive made from calcined alumina. It’s widely used for clean, non-contaminating, precision blasting.
Chemical composition
| Component | Specification |
|---|---|
| Al₂O₃ | ≥99.5% (99.3%–99.7%) |
| Fe₂O₃ | ≤0.05% (≤0.03% for food-grade) |
| Na₂O | ≤0.26% |
| SiO₂ | ≤0.10% |
| CaO + MgO | ≤0.04% |
| Magnetic Impurities | ≤20 ppm |
| Free Silica (α‑quartz) | <1.0% |
Physical Properties:
| Property | Value |
|---|---|
| Appearance | White angular grit, no discoloration |
| Whiteness | ≥85 |
| Mohs Hardness | 9.0 |
| Knoop Hardness | 2,100–2,200 kgf/mm² |
| True Density | 3.95–3.97 g/cm³ |
| Bulk Density | 1.75–1.95 g/cm³ (varies by grit) |
| Melting Point | 2,250°C |
| Refractoriness | 2,100°C |
| pH Value | 8.5 ± 1.5 |
| Conductivity | ≤200 μS/cm |
| Oil Absorption | ≤8% |
| Crystal Form | α‑Al₂O₃ (corundum) |
Key Properties
- White / light gray
- High hardness: Mohs 9
- Al₂O₃ ≥ 99%
- No iron, no rust contamination
- Friable: sharp edges break down, so it’s less aggressive than brown fused alumina
Main Uses
-
Stainless steel blasting
- Clean, passivate, matte finish
- No discoloration, no rust spots
-
Aluminum & non-ferrous parts
- Deburring, cleaning, cosmetic finish
- Won’t embed iron particles
-
Precision & medical parts
- Clean without dimensional damage
-
Coating preparation
- Creates excellent adhesion for paint, PTFE, plating
-
Mold cleaning
- Safe for tool steel, plastic molds
Advantages of White Aluminum Oxide for Blasting
1. No iron contamination — No rust spots
- Contains almost no iron (Al₂O₃ ≥ 99%)
- Will not leave iron particles embedded in aluminum, stainless steel, or copper
- Surface stays clean, bright, rust-free
2. Extremely clean & bright finish
- Produces a white, uniform matte
- Much cleaner than brown fused alumina
- Ideal for high-end cookware, appliances, medical parts
3. Gentler on thin/soft materials
- More friable (breaks into sharp small grains)
- Less aggressive → less risk of warping, denting, or thinning thin aluminum die‑cast pots
4. Perfect for non-stick / PTFE / coating preparation
- Creates excellent micro-roughness for strong adhesion
- No contamination → coatings bond better and last longer
- No fish eyes, peeling, or blistering
5. Suitable for food-contact & medical products
- High purity
- Non-toxic, no heavy metals
- Widely accepted for cookware, kitchen utensils, medical devices
6. No discoloration on stainless steel & aluminum
- Does not cause darkening or staining
- Maintains metal’s original bright appearance
7. Low dust, good recycling
- Clean abrasive, reusable many times
- Stable performance in automatic blasting machines