Brown Fused Alumina (BFA) Polishing Powder?
It is an abrasive powder manufactured by fusing high-quality bauxite (an aluminum ore) in an electric arc furnace at temperatures exceeding 2000°C. The resulting material is then crushed, milled, and precisely graded into various particle sizes (grits) suitable for polishing.
Chemical Composition: Primarily α-Aluminum Oxide (Al₂O₃) (≥95%), with minor impurities like silica (SiO₂), iron oxide (Fe₂O₃), and titanium oxide (TiO₂), which give it its characteristic brown color.
Process: Known as “fused” because the raw materials are melted and then cooled into a solid mass (a “fused lump”) before being processed into powder.
Key Properties
High Hardness: Mohs hardness of 9.0, making it excellent for processing hard materials.
Good Toughness: Less brittle than white fused alumina, it can withstand higher pressure and is suitable for heavy-duty applications.
Self-Sharpening: Grains fracture under pressure to reveal new, sharp cutting edges, ensuring consistent performance over time.
Chemical Stability: Generally inert and resistant to most chemicals, making it suitable for use with various coolants and in different environments.
Angular Grain Shape: The crushed grains have sharp, blocky shapes, which provide aggressive cutting action.
Primary Applications
It is a versatile, cost-effective abrasive used across many industries for rough polishing, lapping, and precision grinding:
Metalworking:
Polishing and deburring of steel, cast iron, and non-ferrous metals.
Blending and finishing of welds.
*Preparing metal surfaces for coating or plating.
Woodworking: Used in coated abrasives (sandpaper) for sanding and shaping hardwoods.
Glass & Stone:
Edge grinding and shaping of glass and architectural stone.
*Lapping of optical components (often in later, coarser stages).
Consumables:
A key ingredient in vibratory tumbling media and blast cleaning abrasives.
*Used in resin-bonded grinding wheels, sharpening stones, and abrasive sticks.
Other Industrial Uses: Cleaning and surface preparation in foundries, shipbuilding, and for manufacturing automotive parts.