Fumed aluminum oxide, or fumed alumina, is a critical material for next-generation energy and coating sectors. Produced via precise flame hydrolysis, SemiAlu™ features a unique positive surface charge and an Al₂O₃ content ≥ 98.0%. It is an essential building block—alongside high-
Core Advantages & Applications
Unique Physicochemical Profile
- High Purity & Fine Particle Size: Prevents contamination in sensitive electronic and ceramic applications.
- Positive Surface Charge: Unlike silica, fumed alumina naturally carries a positive charge, making it ideal for interacting with negatively charged surfaces.
- Thermal Stability: Maintains structural integrity and insulating properties at extreme temperatures.
Energy & Electronics
- Li-ion Battery Separators: Acts as a ceramic coating to significantly increase thermal stability and safety.
- Anode Modification: Improves conductivity and reversible capacitance in lithium batteries.
- Lighting Industry: Used in fluorescent coating powders to ensure uniform light output and reduce UV harm.
Coatings, Inks & Specialty
- Powder Flow & Anti-Caking: Improves flowability and charge ability for powder coatings and printing inks.
- Rheology Control: Acts as a highly effective thickening and thixotropic agent with high transparency in UV-curable systems.
- Specialty Binders: Essential for high-temperature refractory castables and insulation boards.
SemiAlu™ Technical Specifications
| Properties | Unit | SemiAlu Value | Testing Method |
|---|---|---|---|
| Specific Surface Area (BET) | m²/g | 100 ± 15 | GB/T 20020 |
| pH in 4% Dispersion | – | ≥ 3.9 | GB/T 20020 |
| Loss on Drying (@ 105°C × 2h) | % | ≤ 2.5 | GB/T 20020 |
| Loss on Ignition (@ 1000°C × 2h) | % | ≤ 2.0 | GB/T 20020 |
| Al₂O₃ Content (Ignited Material) | wt.% | ≥ 98.0 | GB/T 20020 |
| Tamped Density | g/dm³ | 50 – 80 | GB/T 20020 |
| Crystal Structure | – | Mixed crystal structure | GB/T 20020 |
Knowledge Base: Frequently Asked Questions
Expert answers to the most common queries regarding fumed aluminum oxide applications and formulation integration.
+What is fumed alumina, and how does it differ from fumed silica?
Fumed alumina (aluminum oxide) is a high-purity synthetic oxide powder produced via flame hydrolysis. The primary difference is its positive surface charge. While fumed silica carries a negative charge, fumed alumina’s positive charge makes it uniquely suited for interacting with negatively charged surfaces, improving dispersion in specific polymer matrices and powder coatings.
+How does SemiAlu fumed aluminum oxide improve Li-ion battery performance?
In Li-ion batteries, SemiAlu is applied as a ceramic coating for separators, which drastically enhances thermal stability and prevents thermal runaway, thereby improving battery safety. Additionally, when applied to the anode, it helps improve conductivity and reversible capacitance.
+Why is a positive surface charge important in fumed alumina applications?
The positive surface charge (indicated by a pH ≥ 3.9 in a 4% dispersion) allows fumed alumina to act as a highly effective anti-caking agent and flow aid. It enhances charge adsorption in melt-blown electret masterbatches and improves the triboelectric chargeability of powder coatings, leading to more uniform application.
+Can high-purity fumed alumina be used as a flow aid and anti-caking agent?
Yes. Due to its superfine particle size, low bulk density (50-80 g/dm³), and high specific surface area (80±15 m²/g), fumed alumina is an exceptional flow aid and anti-caking agent. It prevents clumping in powder coatings, toners, and printing inks while simultaneously acting as a thixotropic thickening agent.
+What are the key technical specifications of SemiAlu fumed aluminum oxide powder?
SemiAlu features a high purity (Al₂O₃ ≥ 98.0%), a specific surface area (BET) of 80±15 m²/g, and a mixed crystal structure. It exhibits excellent thermal stability with a loss on ignition of ≤ 2.0%, making it ideal for high-temperature refractory castables and specialty optical coatings.
Battery Applications
Fumed Alumina in Lithium Battery
SEMITECH fumed alumina is a critical material across two layers of the lithium battery cell — the ceramic-coated separator and the high-nickel cathode surface coating. Both applications rely on alumina’s high purity, narrow particle size, and chemical inertness toward lithium electrolyte.