The Main Applications of Brown Corundum in Zinc Sheet Sandblasting
The primary purpose of sandblasting zinc sheet is typically not to remove a large amount of the base material, but rather to achieve a specific surface effect. Due to its unique properties, brown corundum is well-suited for these tasks:
Cleaning and Decontamination: Removes oxide layers, light oil stains, impurities, and other contaminants from the zinc sheet’s surface during transportation and storage, providing an absolutely clean base for subsequent painting or bonding.
Surface Roughening: This is the primary application. Sandblasting creates a uniform, slightly rough anchor pattern on the smooth zinc surface. This significantly increases the surface area, improving adhesion between paint, coatings, or adhesives and the zinc sheet, and preventing coating detachment.
Achieving a Consistent Appearance: Eliminates surface defects such as mold marks and weld marks, achieving a uniform, matte finish across large batches of zinc sheet.
Decorative Finishes: Various matte or frosted finishes can be created to meet the aesthetic needs of applications such as architecture and home appliances.
II. Application Process and Key Parameters
The application of brown corundum for zinc plate sandblasting requires a standard sandblasting system and rigorous process control.
Basic Process:
Compressed air → Pressure regulation → Injection of brown corundum abrasive → Acceleration through the nozzle → Impact on the zinc plate surface
Why choose brown corundum?
Compared to other abrasives, brown corundum offers unique advantages for zinc plate sandblasting:
High Hardness and Sharp Angularity: Brown corundum has a Mohs hardness of 9.0, second only to diamond and silicon carbide. Its sharp angular grains effectively cut and roughen the zinc surface, creating the ideal anchor pattern.
Good Toughness: It is not easily broken and can be reused a high number of times (typically 2-4 times, depending on pressure and cleanliness), reducing overall operating costs.
Low Impurities and Low Contamination: Brown corundum is of high purity, resulting in minimal residue after sandblasting and no iron ion contamination on the zinc plate surface (preventing “flash rust”), which is crucial for subsequent high-quality painting.
High efficiency: Due to its hardness and toughness, under the same conditions, it can reach the target roughness faster than some soft abrasives.