How to judge the quality of brown corundum?
The quality of brown corundum needs to be comprehensively evaluated from multiple dimensions such as appearance, physical properties, chemical composition and production standards. The specific methods are as follows:
1. Appearance judgment
Color
High-quality products usually appear dark brown-red, dark brown or tan, with uniform color and good light transmittance. If it appears abnormally bright, black or rose color, there may be impurities or too high iron content.
Brown corundum with smaller particles is lighter in color, and large particles are darker in color, but attention should be paid to the overall color consistency.
Particle shape and uniformity
The particles should be regular hexagonal or spherical, uniform in size, without obvious agglomerates or impurities. The more uniform and fine the particle size, the higher the grinding efficiency.
Transparency
When observed in the sun, products with high transparency and slightly green color have higher hardness and better iron content.
2. Physical property testHardness
Measured by a hardness tester (Vickers or Rockwell), high-quality brown corundum has moderate hardness and high compressive strength. It can also be tested by hand pressure: take a small amount of particles and place them on white paper. If they are fragile, the hardness is insufficient.
Magnetic material detection
Use a magnet to absorb the sample. The less magnetic material, the lower the impurity content and the higher the purity of alumina.
Wear resistance and ash content test
Wear resistance can be compared with standard samples by a wear tester; the ash content can be soaked in clean water. If white matter appears on the water surface, the ash content is high, otherwise the quality is better.
3. Chemical composition analysis
Alumina (Al₂O₃) content
The Al₂O₃ content of the first-grade brown corundum must be ≥95%, and the second and third grades decrease in turn. High-purity products have better grinding efficiency and durability.
Impurity control
Impurities such as iron and silicon will affect hardness and performance, which can be detected by chemical analysis or spectral analysis.
4. Other reference factors
Packaging and labeling
Regular products are packaged completely, and the label clearly indicates the product name, specifications, weight and implementation standards.
Manufacturer qualifications
Choose a regular manufacturer with a strict quality inspection process to ensure that the product meets industry standards (such as GB/T 2478-2023).
Price Reasonability
High-quality products are more expensive, but the price-performance ratio is better than low-priced and inferior products. You need to consider the budget and needs comprehensively.
Comprehensive suggestions
Give priority to products with uniform color, fine particles, hardness that meets the standard, and high Al₂O₃ content, and purchase them through regular channels to ensure quality. If conditions permit, you can entrust a third-party agency to conduct chemical composition and wear resistance testing.