White Fused Alumina (WFA) Micro Powder, chemically high-purity alpha-alumina (α-Al₂O₃) with a typical purity exceeding 99.0% (and ultra-high purity grades up to 99.99% available), is a premium, ultra-fine ceramic abrasive powder.
White Fused Alumina (WFA) Micro Powder, chemically high-purity alpha-alumina (α-Al₂O₃) with a typical purity exceeding 99.0% (and ultra-high purity grades up to 99.99% available), is a premium, ultra-fine ceramic abrasive powder. Produced by fusing high-purity alumina (or calcined bauxite) in an electric arc furnace at temperatures above 2,000°C, followed by air cooling, crushing, and ultra-fine milling, it is distinguished by its brilliant white color and dense, crystalline structure. With a Mohs hardness of 9.0 and a Vickers hardness of 2,200–2,400 HV, WFA micro powder is valued for its superior hardness, sharp cutting edges, and chemical inertness, making it ideal for ultra-precision applications where surface quality is paramount. Particle sizes for micro powder grades typically range from 0.1 μm to 20 μm, with tightly controlled particle size distributions (PSD) for consistent performance.
• High Purity & Color: Characterized by its bright white color, a direct result of extremely low levels of impurities (e.g., Fe₂O₃ <0.05%, TiO₂ <0.1%, SiO₂ <0.2%). Ultra-high purity grades minimize contamination in critical applications like electronics and optics.
• Hardness & Self-Sharpening: Exceptional hardness combined with a more brittle crystalline structure compared to brown fused alumina (BFA). Under load, the sharp, angular particles fracture to form new, sharp cutting edges (self-sharpening), ensuring high material removal rates and a superior surface finish.
• Thermal Stability: Outstanding thermal resistance with a melting point of 2,050°C and low thermal expansion (7.6 × 10⁻⁶ /°C), making it suitable for high-temperature applications and thermal spray coatings.
• Chemical Inertness: Highly resistant to acids, alkalis, and most organic solvents at ambient and moderate temperatures. Its chemical stability ensures compatibility with a wide range of binders and matrices.
• Density: True density of 3.95–4.0 g/cm³ and bulk density of 1.5–1.8 g/cm³, offering good packing efficiency in composite materials and coatings.
• Particle Size Distribution (PSD): Narrow, tightly controlled PSD (e.g., D50 = 1–5 μm) with minimal agglomeration, ensuring uniform dispersion and consistent performance in slurries, pastes, and coatings.
• Morphology: Sharp, angular, and dense crystalline particles with a well-defined alpha-alumina structure, providing excellent cutting action and surface finishing capabilities.
• Surface Properties: Hydrophilic surface with high surface energy, enabling excellent wetting and dispersion in water-based and solvent-based systems (compatible with epoxy, phenolic, acrylic, and other binders).
1. Ultra-Precision Polishing & Lapping: The material of choice for producing mirror-like finishes on hard, brittle materials such as tungsten carbide, ceramics (Al₂O₃, ZrO₂), glass, silicon wafers, sapphire, and optical components. It delivers surface roughness (Ra) as low as 0.01 μm.
2. Semiconductor & Electronics Manufacturing: Critical component in Chemical Mechanical Planarization (CMP) slurries for polishing silicon wafers and in the production of ceramic substrates, thick-film pastes, and electronic-grade refractories.
3. Precision Grinding of Hardened Steels: Used in grinding wheels, honing stones, and abrasive belts for the precision grinding of high-speed steel, tool steel, and bearing steel, where a high-quality, burr-free finish is essential.
4. Functional & Protective Coatings: As a reinforcing additive in thermal spray (HVOF, plasma) coatings and anti-corrosion/anti-wear coatings for aerospace components, automotive parts, and industrial machinery, enhancing hardness, wear resistance, and thermal barrier properties.
5. Advanced Ceramics & Refractories: A high-purity raw material for manufacturing high-strength alumina ceramics, advanced refractories, and investment casting shells, ensuring superior mechanical and thermal properties.
White Fused Alumina (WFA) Micro Powder is non-toxic but is a fine dust that can cause respiratory irritation if inhaled or eye irritation upon contact. It should be handled in a well-ventilated area with appropriate personal protective equipment (PPE), including N95/P100 respirators and safety goggles. Store in a dry, sealed container at room temperature to prevent moisture absorption (which can cause clumping) and avoid prolonged exposure to strong acids at high temperatures (which may react to form aluminum salts).
This micro powder is a high-performance, premium abrasive material, prized for its purity, hardness, and ability to deliver ultra-smooth surfaces. It is indispensable in the most demanding precision manufacturing processes across the aerospace, electronics, automotive, and optical industries.
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