1. Definition & Manufacturing Process

White Fused Alumina Micro Powder (WFA Micro Powder) is a high-purity synthetic abrasive composed of ≥99% aluminum oxide (Al₂O₃). It is produced by melting calcined alumina in electric arc furnaces at temperatures exceeding 2200°C, followed by crushing, grinding, and advanced micronization processes to achieve particle sizes as fine as 1–20μm (FEPA F240–F4000)19.

Key Production Steps:

1. Raw Material: High-purity alumina (Al₂O₃ ≥99.5%)1.

2. Melting & Cooling: Forming dense alpha-Al₂O₃ crystals in arc furnaces13.

3. Micronization: Wet grinding and air classification to achieve precise particle size distributions912.

4. Quality Control: Magnetic separation to reduce Fe₂O₃ (<0.02%) and ensure low contamination210.

2. Key Properties

Chemical & Physical Characteristics

• Purity: Al₂O₃ ≥99%, Fe₂O₃ ≤0.02%, SiO₂ ≤0.05%18.

• Hardness: Mohs 9.0 (comparable to sapphire), Knoop hardness 2000–2200 kg/mm²913.

• Thermal Stability: Melting point 2250°C, usable up to 1900°C210.

• Particle Shape: Angular to near-spherical (post-spheroidization)912.

• Density: True density 3.95 g/cm³, bulk density 1.55–1.95 g/cm³212.

Advantages Over Alternatives

• Higher Purity: Lower impurities vs. brown fused alumina (Fe₂O₃ ≤0.05%)1.

• Sharper Cutting Edges: Superior to calcined alumina in precision grinding12.

• Recyclability: 5–7 cycles in sandblasting, reducing waste costs2.

3. Industrial Applications

A. Precision Surface Finishing

• Semiconductor Wafer Polishing: Achieves Ra ≤0.05μm for silicon wafers (F1000–F2000 grit)812.

• Optical Components: Used for lens polishing (e.g., camera, VR optics) with minimal subsurface damage811.

• Medical Devices: Non-toxic, FDA-compliant polishing for implants and surgical tools210.

B. High-Performance Coatings

• Thermal Spray Coatings: Enhances wear resistance in aerospace components (e.g., turbine blades)1113.

• Ceramic Membranes: Improves filtration efficiency in water treatment systems12.

C. Advanced Manufacturing

• 3D Printing: Used in binder jetting for high-resolution metal parts (D50=15–25μm)6.

• Electronics: Polishing LED substrates and vacuum-sputtered components810.

D. Refractories & Ceramics

• Ladle Linings: Aggregates (1–3mm) for steelmaking furnaces, resisting slag corrosion613.

• High-Alumina Ceramics: Boosts compressive strength (≥2500 MPa) in ballistic armor6.

4. How to Choose the Right WFA Micro Powder

Grit Size Selection

Purity Grades

• Standard (99% Al₂O₃): General industrial use (e.g., refractory castables).

• High-Purity (99.8% Al₂O₃): Critical for electronics and medical devices.

Supplier Criteria

• Certifications: ISO 9001, FEPA/JIS compliance.

• Particle Size Consistency: ≤±5% deviation from nominal size.

• Customization: Availability of low-sodium (Na₂O ≤0.1%) variant

6. Future Trends & Innovations

• AI-Driven Grit Optimization: Machine learning models to match grit size with material hardness.

• Eco-Friendly Production: Recycling 95% of process water in micronization.

• Nano-Coating Applications: Sub-100nm particles for anti-reflective coatings in solar panels.