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W Microgrit for Lapping & Polishing (White Fused Alumina Micropowder)

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W Microgrit for Lapping & Polishing (White Fused Alumina Micropowder)
W microgrit for lapping and polishing is produced from low-sodium industrial alumina through electric-arc fusion, cooling and crystallization, followed by crushing, acid washing, magnetic separation, and multi-stage hydraulic overflow classification. The main crystalline phase is α-Al₂O₃, appearing pure white with angular grain morphology. Al₂O₃ content is typically 99.2%~99.6% or higher, with Fe₂O₃ and Na₂O held at low levels to prevent metallic contamination or rust staining during precision polishing.

Product Specifications

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Item Typical Value
Color Pure white
Crystal Form α-Al₂O₃, angular
Mohs Hardness 9.0
Knoop Hardness 2000 kg/mm²
Melting Point Approx. 2250℃
Service Temperature Approx. 1900℃
Specific Gravity (True Density) 3.95 g/cm³
Bulk Density (Volume) 3.6 g/cm³
Loose Bulk Density 1.55~1.95 g/cm³
Grain Characteristics Angular, self-sharpening, tight particle size distribution, strict oversized-particle control

The above physical values synthesize published technical data for W microgrit.

Chemical Composition

Constituent General Polishing Grade (%) Low-Sodium/High-Purity Grade (%)
Al₂O₃ ≥99.2 ~ ≥99.4 ≥99.6 ~ ≥99.7
Fe₂O₃ ≤0.04 ~ ≤0.06 ≤0.03
Na₂O ≤0.28 ~ ≤0.30 ≤0.10 (custom ≤0.05)
SiO₂ ≤0.15 —
CaO ≤0.03 —

General-grade values reference the typical chemistry of commercial polishing-grade W microgrit; low-sodium/high-purity values derive from ultra-low-sodium white fused alumina micropowder specifications, with Na₂O controllable below 0.10% for semiconductor CMP, optical glass finishing, and similar demanding applications. Strict Fe₂O₃ control is particularly critical for stainless and carbon steel polishing to avoid rust spots or yellow staining.

Production Specifications

W microgrit is supplied under the Chinese GB W-series and can be cross-referenced to FEPA (F) and JIS mesh systems. The W range covers W63 (rough polishing) through W0.5 (ultra-precision polishing), with D50 values decreasing from approximately 63 μm to sub-micron levels.

W Grade (GB) Reference D50 (μm) FEPA Equivalent JIS Mesh Equivalent Typical Polishing Stage
W63 63~50 F230 #240 Rough lapping / removal of tool marks
W50 50~40 F240 #280 Rough lapping
W40 40~28 F280/F320 #320/#400 Rough to medium polishing
W28 28~20 F320/F360 #400/#500 Medium polishing
W20 20~14 F400/F500 #600 Medium to fine polishing
W14 14~10 F500/F600 #800 Fine polishing
W10 10~7 F600/F800 #1000 Fine / pre-finishing polish
W7 7~5 F800/F1000 #1200 Pre-mirror polishing
W5 5~3.5 F1000/F1200 #1500 Precision polishing
W3.5 3.5~2.5 F1200/F1500 #2000 Precision polishing
W2.5 2.5~1.5 F1500/F2000 #2500 Ultra-precision polishing
W1.5 1.5~1.0 F2000+ #3000~#4000 Ultra-precision polishing
W0.5 ≤0.5 Custom ultrafine #8000~#10000 Final mirror polishing

The W-to-FEPA and W-to-JIS cross-references follow general industry comparison tables. In practice, stepwise progression through grits is recommended rather than skipping from coarse to fine, and wet lapping (water or lapping fluid) generally outperforms dry processing in reducing scratches.

Application Scenarios

Precision Metal Polishing (Core Application):

Stainless & Carbon Steel Components: Valves, fasteners, kitchen hardware, and precision mechanical parts in vibratory finishing, barrel polishing, and surface lapping. Low Fe₂O₃ content is critical to avoid rust spots and yellow staining, outperforming brown fused alumina.

Molds & Alloy Steel: Pre-polishing and fine polishing of injection molds, die-casting molds, and alloy steel parts. W10~W5 grades are commonly used in polishing paste and polishing wax formulations.

Copper & Aluminum Alloys: Suitable for general polishing, though pure aluminum and pure copper are soft and may require finer grades or silica-based alternatives to avoid deep scratches.

Hard & Brittle Materials / Electronics:

Semiconductors & Electronic Components: Silicon wafers, SiC wafer thinning, and electronic ceramic substrate lapping. Low-sodium and ultra-low-sodium grades (Na₂O ≤0.05%) are used in CMP slurries and precision electronic polishing where contamination and micro-scratch control are paramount.

Optics & Crystals: Precision lapping and polishing of optical glass, quartz crystals, sapphire substrates, crystal glass, and lenses. W7~W1.5 represents the common range for optical mirror pre-polishing.

Ceramic Substrates: Double-side lapping of alumina ceramic substrates—W40/W28 for rough lapping, W20/W14 for intermediate lapping, and W10/W7 for fine lapping, progressively reducing surface roughness.

Oilstones, Polishing Wheels & Compounds:

Raw material for superfinishing oilstones, fiber polishing wheels, PVA polishing wheels, and nylon grinding heads; abrasive component in polishing pastes, waxes, and lapping slurries.

Other Extensions:

Precision Casting & Refractories: Precision casting sand and fine powder component in advanced refractories.

Surface Treatment & Coatings: Functional filler in wear-resistant coatings, industrial ceramics, and lithium battery separator coatings.

Our Facilities

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  • 1773993031893525296293171200
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  • 1789955364129206

FAQ

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Q1: Is your company a trading firm or a manufacturing plant? Where are your facilities located?
We are an export-oriented enterprise that integrates manufacturing and sales; we are not an intermediary. Our headquarters—handling international sales, order processing, documentation, and after-sales service—is located in the Liaocheng Economic and Technological Development Zone, serving as the hub for global client relations, order negotiations, and cross-border services. Our production facility is situated in Chiping District, Liaocheng City, and specializes in the R&D, smelting, processing, and testing of white fused alumina, brown fused alumina, and other fused alumina products. This allows us to manage the entire supply chain—from primary production and rigorous quality control to direct export.


Q2: What is your production capacity and supply capability? Can you ensure a stable, long-term supply?
Our production base in Chiping features mature production lines and comprehensive processing equipment, enabling large-scale, continuous manufacturing. We offer a stable supply of our full range of white fused alumina, brown fused alumina, and related fused alumina products. With ample inventory and well-organized production scheduling, we are fully equipped to handle bulk orders, recurring annual orders, and urgent requests during peak seasons, ensuring a reliable, long-term supply for our global clients.


Q3: What are your primary export products, and what are your core offerings?
Our core exports consist of three main series of fused alumina materials: brown fused alumina, white fused alumina, and other fused alumina products. We offer a comprehensive range of specifications and particle sizes that meet various international procurement standards. Brown fused alumina is our flagship product for cost-effective industrial abrasives and refractory raw materials; white fused alumina is designed for high-purity, high-precision grinding and polishing applications; and our broader fused alumina line serves high-end refractory, specialty ceramic, and precision abrasive tool sectors—covering the full spectrum of procurement needs across all market tiers.


Q4: What are the specific applications for these three types of fused alumina, and how should one choose the right product? 1. Brown Fused Alumina: Characterized by high toughness, excellent wear and impact resistance, and a strong price-performance ratio. It is suitable for general industrial applications such as metal sandblasting (rust removal), hardware grinding, the manufacturing of grinding wheels and sandpaper, metallurgical castable refractories, and lining materials for standard industrial furnaces. It serves as a versatile, all-purpose abrasive and refractory raw material.

2. White Fused Alumina: Features high purity, high hardness, and excellent self-sharpening properties, with a pure white appearance free from impurities. It is ideal for high-precision and high-cleanliness applications, including the polishing of precision molds, grinding of aerospace components, finishing of electronic materials, and the production of high-end refractory products and precision ceramics.

3. Fused Alumina (High-Purity/Specialized): Possesses a dense structure, exceptional thermal stability, and high resistance to both heat and corrosion. It serves as a core raw material for high-end, specialized refractories, structural ceramics, precision grinding media, and linings for high-temperature industrial kilns, making it well-suited for demanding, high-performance operating environments.

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