| 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 |
Expert answers to the most common queries regarding fumed aluminum oxide applications and formulation integration.
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.
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.
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.
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.
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.
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.
Raise separator thermal stability above 180 °C, suppress shrinkage, and improve electrolyte wettability for high-energy NMC and NCA cells.
Form a 2–5 nm protective layer on NMC811, NCA, and Ni-rich cathodes — suppressing cation mixing and gas evolution.