production process

Raw material selection and processing

High purity alumina powder: Alpha alumina (purity 90% -99.9%) is usually selected due to its high hardness and stability.

Additives: Add a small amount of binders (such as polyvinyl alcohol), plasticizers, or sintering aids (such as MgO, SiO ₂) to improve molding and sintering properties.

Ball milling mixing: The raw materials are mixed by wet ball milling to ensure uniformity, and the slurry particle size reaches the micrometer level.

Forming process

Granulation and pressing: after spray drying granulation, dry pressing or isostatic pressing is used to form a spherical green body.

Grouting molding: suitable for complex shapes, dried after grouting through gypsum molds.

sintering process 

High temperature sintering: Sintering in a tunnel kiln or shuttle kiln at 1600-1800 ℃ to form a dense structure with a shrinkage rate of about 15-20%.

Atmosphere control: Some processes require an inert atmosphere (such as nitrogen) to prevent oxidation.

Post processing and quality inspection

Precision polishing: High precision grinding balls require surface treatment to ensure roundness error<0.1mm.

Grading screening: Classify by particle size (such as Φ 1mm - Φ 50mm) using a vibrating screening machine.

Performance testing: Testing hardness (Hv ≥ 1500), density (≥ 3.6g/cm ³), and wear resistance (wear<0.01%).

Main purpose

Powder processing field

Ceramic industry: Grinding kaolin and quartz sand to D50<1 μ m to improve the density of the body.

Electronic materials: used for grinding MLCC barium titanate powder, with a purity requirement of>99.5%.

Lithium battery materials: Nano scale dispersion of positive and negative electrode materials (such as LiCoO ₂) with particle size controlled within ± 50nm.

Special application scenarios

High temperature environment: Can withstand 800 ℃ working conditions in refractory material ball milling, replacing steel balls to avoid metal contamination.

Chemical catalysis: As a catalyst carrier (such as Pd/Al ₂ O3), with a specific surface area greater than 200m ²/g.

Biomedical: Aseptic grinding of antibiotic raw materials, in compliance with GMP standards.

Precision machining

Optical glass polishing: used for CMP process of mobile phone cover glass, with surface roughness Ra<0.5nm.

Semiconductor wafer: silicon wafer thinning and grinding, with a thickness tolerance of ± 1 μ m.

Performance advantages and limitations

Advantages: Mohs hardness level 9, wear resistance three times that of ordinary steel balls; Acid and alkali resistant (pH 1-14); Good insulation performance (resistance>10 ΩΩ· cm).

Limitations: The density is 3.6-3.9g/cm ³, which is 30% lower than the grinding efficiency of zirconium balls (6.0g/cm ³); High brittleness and inferior impact resistance compared to metal balls.

market trends 

High end development: The demand for 99.99% ultra-high purity alumina balls is increasing by 12% annually, used for the production of 5G ceramic filters.

Composite improvement: The impact toughness of alumina zirconia composite balls (ZrO ₂ 20%) has been increased by 50%.