Production Process of Tabular Alumina
Tabular alumina is a high-performance aluminum oxide material named for its plate-like or tabular crystal microstructure. Known for its exceptional high-temperature resistance, mechanical strength, and chemical stability, it is widely used in refractory materials, ceramics, electronic components, and other fields.
Production Process of Tabular Alumina
1. Raw Material Selection and Pretreatment
【1】High-purity alumina raw material: Industrial alumina powder with ≥99% α-Al₂O₃ content ensures final product purity.
【2】Additive control: Trace mineralizers (e.g., aluminum fluoride, boric acid) are added to optimize sintering and minimize impurity retention.
【3】Ball milling: Wet ball milling reduces particle size to micrometer scale (D50 ≤ 5 μm), enhancing reactivity.
2. Forming Technology
【1】Dry pressing: High-pressure (100–200 MPa) compaction ensures uniform green body density.
【2】Isostatic pressing: For complex shapes, cold isostatic pressing (CIP) improves compact density.
3. High-Temperature Sintering
【1】Temperature control: Sintering at 1800–1950°C promotes directional growth of α-Al₂O₃ grains.
【2】Atmosphere regulation: Conducted in an oxidizing environment (air or oxygen) to prevent reduction reactions.
【3】Holding time: Adjusted based on product size (typically 6–12 hours) to ensure complete grain development.
4. Post-Processing
【1】Crushing & sieving: Sintered blocks are processed via jaw crushers and multi-stage vibrating screens to obtain target particle sizes (mainly 0.1–3 mm).
【2】Surface modification: Acid washing or coating is applied for specific applications to enhance interfacial bonding.
Applications & Market Value
1. Refractory Industry
【1】Ladle castables: Used as aggregates to improve spalling resistance, extending lining life by >30%.
【2】Purging bricks: For steel refining, with precise porosity control (15–25%) and excellent gas permeability.
2. Advanced Ceramics
【1】Electronic substrates: Matches semiconductor packaging requirements (dielectric constant: 9.8 @1MHz; CTE: 8.1×10⁻⁶/°C).
【2】Wear-resistant parts: For ceramic cutting tools and nozzles (Vickers hardness: 2200 HV).
3. Environmental & New Energy
【1】Catalyst carriers: Controlled surface area (0.5–5 m²/g) for automotive SCR systems.
【2】Photovoltaic crucibles: Inner coatings for polysilicon ingot crucibles (purity: 6N standard).
