Calcined alumina for polishing grade is a high-purity white powder, used as a fine polishing material for glass, rhinestones, crystals, wafers, metals, and various stone series. It has high grinding efficiency and excellent polishing effect, with a much higher grinding efficiency than soft abrasive materials such as silica. The surface finish is superior to that of white corundum polishing. It has strong cutting force, fast polishing speed, and can produce uniform and bright luster. Different polishing processes are determined based on the average particle size. Generally, particles with a size of 10-20 μm are used in the rough polishing process, 3-10 μm in the medium polishing process, 1-3 μm in the fine polishing process, and those smaller than 1 μm are used in mirror polishing. The narrower the particle size distribution, the higher the polishing efficiency.
Performance Features
High hardness
Calcined alumina Mohs hardness can reach around 9, second only to diamond. It can effectively grind and polish various material surfaces, remove scratches, flaws, etc., and improve surface smoothness.
01
Good wear resistance
During polishing, its own wear is relatively small, which can maintain a stable polishing effect and extend the service life of polishing tools.
02
Chemical stability
It has excellent corrosion resistance and does not react with most chemical substances. It can be used in different chemical environments to ensure that the material surface is not chemically eroded during polishing.
03
Precise particle size distribution
According to different polishing processes and requirements, it has a narrow and precise particle size distribution, such as 20-45μm particle size for rough polishing, 4-20μm particle size for medium polishing, 1-4μm particle size for fine polishing, and 1μm and below for mirror polishing.
04
Uniform particle shape
The particles are mostly round, elliptical or close to spherical, with smooth surfaces. Such particles are less likely to cause scratches during polishing, making the polished surface more smooth.
05
Production Process
Raw material preparation
Generally, industrial-grade aluminum hydroxide or crystalline alumina are used as the main raw materials. Sometimes, a certain proportion of fluxes such as borates and silicates are added to lower the melting point and improve the crystal structure.
Ball milling
The raw materials are added to the ball mill and ground by high-speed rotating steel balls to reach the required fineness and uniformity. During ball milling, the ball milling time and speed need to be controlled properly.
Forming
After ball milling, the alumina powder is formed into various shapes through methods such as pressing, injection molding, and extrusion molding, such as tubular, plate-like, and block-like shapes, or micrometer or nanometer-sized particles.
Sintering
The formed alumina products are placed in a high-temperature furnace for sintering to make the internal grains grow and combine together to form a dense structure. The sintering process requires strict control of temperature and time.
Processing
The sintered alumina products can be further processed through methods such as cutting, polishing, and electroplating to meet the requirements of different application scenarios.
Testing
After processing, the alumina products are subjected to performance tests, such as hardness, wear resistance, and corrosion resistance, to ensure that their quality meets the requirements.
|
Polishing Grade |
Model |
Al2O3(%) |
Na2O(%) |
D50 |
Surface area(m2/g) |
Primary crystal size |
Oil Absorption |
|
Rough polishing |
Y-C-101 |
99.5 |
0.3 |
10 |
0.5 |
6 |
25 |
|
Y-C-102 |
99.5 |
0.3 |
6 |
0.7 |
6 |
20 |
|
|
Moderate Polishing |
Y-C-201 |
99.6 |
0.2 |
10 |
1.0 |
2 |
30 |
|
Y-C-202 |
99.7 |
0.1 |
3 |
1.5 |
2 |
25 |
|
|
Fine polishing |
Y-C-301 |
99.5 |
0.3 |
3 |
10 |
1 |
30 |
|
Y-C-302 |
99.6 |
0.2 |
1.8 |
5 |
0.5 |
35 |
|
|
Y-C-303 |
99.7 |
0.1 |
0.8 |
6 |
0.4 |
35 |
Calcined Alumina For Polishing Grade Application Fields
Optical lens polishing
In the manufacturing process of optical lenses such as eyeglass lenses, camera lenses, and telescopic lenses, polishing-grade calcined alumina is widely used, which can precisely control the flatness and smoothness of the lens surface, improve the optical performance of the lenses, and reduce light refraction and scattering.
Electronic component polishing
For the manufacturing of electronic components such as semiconductor chips, integrated circuit boards, and electronic displays, polishing-grade calcined alumina is used to flatten the surface of the components to ensure the stability and reliability of the electronic components.
Gemstones and jewelry processing
In the cutting and polishing process of gemstones and jewelry such as diamonds, rubies, sapphires, and jade, polishing-grade calcined alumina can effectively remove impurities and flaws on the surface of the gemstones, making the gemstones present a brilliant luster and charming colors.
Ceramic and glass polishing
This process is used for polishing the surfaces of ceramic products such as tiles, ceramic tableware, ceramic artworks, etc., and glass products such as flat glass, glassware, decorative glass, etc. Calcined alumina for polishing can enhance the smoothness and transparency of the ceramic and glass surfaces, thereby improving their aesthetic appeal and practicality.
Metal Polishing
It is used for polishing the metal parts of vehicles such as wheels and body decorations, etc., to make the metal surface present a high gloss and improve the appearance quality of the products. Calcined alumina can also be used for polishing stainless steel kitchenware, tableware, bathroom hardware, etc., making the surface smooth and bright, easy to clean, and improving corrosion resistance.
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