Alumina (aluminium oxide, Al₂O₃) is one of the most useful industrial materials. It is very hard, resists high temperatures and does not react easily with most chemicals. White fused alumina is one of its most widely used forms, especially where hardness and purity both matter.
What is white fused alumina?
White fused alumina, often shortened to WFA, is made by melting high-purity alumina in an electric arc furnace at more than 2,000 °C. The melt is then cooled, crushed and graded into grains and powders of different sizes.
Melting and re-solidifying the alumina gives large, dense crystals of alpha-alumina, the hardest and most stable form. The result is a white material with high purity and very high hardness, about 9 on the Mohs scale. Only diamond and a few other materials are harder.
White vs brown fused alumina
You will often see white fused alumina compared with brown fused alumina. Brown fused alumina is made from bauxite and keeps some titanium oxide and other impurities. That makes it tougher and cheaper, but less pure.
| Property | White fused alumina | Brown fused alumina |
|---|---|---|
| Raw material | High-purity alumina | Bauxite |
| Purity | High Al₂O₃, low impurities | Lower; contains TiO₂ and others |
| Colour | White | Brown |
| Behaviour | Very hard, sharper and more friable | Tougher, more impact-resistant |
| Typical choice when | Purity, cool cutting or no colour contamination matter | Heavy-duty grinding at lower cost |
“Friable” means the grain breaks down gradually during use and exposes fresh sharp edges. This helps white fused alumina cut cleanly and cool, which is why it is popular for precision grinding and polishing.
Where white fused alumina powder is used
- Abrasives and polishing: grinding wheels, coated abrasives, lapping and polishing compounds, and blasting media for surface preparation.
- Refractories: grains and fines in castables, bricks and ramming mixes that must handle high temperatures.
- Technical and structural ceramics: where hardness, wear resistance and electrical insulation are needed.
- Thermal spray and coatings: as a feedstock for hard, wear-resistant ceramic coatings.
- Catalyst supports and fillers: where an inert, hard, heat-resistant filler is needed.
How to specify white fused alumina
To get the right material, share these details when you enquire:
- Al₂O₃ content and your limits on impurities such as Na₂O, Fe₂O₃ and SiO₂.
- Grit or particle size: the FEPA or mesh grit size for abrasive grains, or a micron range for fine powders.
- Particle size distribution: especially important for polishing and thermal spray.
- Bulk density: useful for refractory and abrasive formulations.
- End use: tell the supplier what the material is for, so they can recommend a suitable grade.
White fused alumina from Powdrox
Powdrox supplies white fused alumina powder, including custom-milled grades and fine and ultra-fine fractions on enquiry. We supply across India and for export, with a Certificate of Analysis and MSDS on request, and small trial quantities are available. Request a quote with your grade, quantity and destination.