Hollow glass microspheres are micron-sized (usually 10-150μm) lightweight spherical particles, consisting of a thin-walled glass shell enclosing a gas (such as nitrogen or carbon dioxide). Due to its unique structure, it has low density, high strength, heat insulation, sound insulation and other characteristics, and is widely used in composite materials, coatings, aerospace, petroleum industry and other fields.
1. Structure and characteristics
(1) Physical structure
Shell: Made of soda-lime-silicon glass or borosilicate glass, with a wall thickness of about 1-2 μm.
Internal gas: Usually an inert gas (N₂, CO₂), providing low density and thermal insulation.
(2) Key performance
Characteristics Typical values Application advantages
Density 0.1-0.6 g/cm³ Lighter than water, reducing material weight
Compressive strength 5-100 MPa Can withstand processing pressure
Thermal conductivity 0.05-0.12 W/(m·K) Excellent thermal insulation performance
Particle size 10-150 μm Easy to disperse in various substrates
Chemical stability Acid and alkali resistant (pH 2-12) Suitable for harsh environments
2. Preparation process
There are two main methods for manufacturing hollow glass beads:
(1) Flame blowing method
Raw materials: glass powder (SiO₂, Na₂O, CaO, etc.) mixed with a foaming agent (such as sodium sulfate).
High temperature melting: Melting at 1400-1600℃, the foaming agent decomposes to produce gas.
Blow molding: Molten glass droplets are blown away by high-speed airflow and form hollow microspheres after cooling.
(2) Sol-gel method
Applicable to high-purity, small-size (<50μm) microbeads, but the cost is relatively high.
3. Main application areas
(1) Lightweight composite materials
Automobile/aerospace: Add plastic, rubber or metal matrix to reduce the weight of components (such as aircraft interiors, car bumpers).
Deep-sea buoyancy materials: Used in submersibles and submarine cables to provide stable buoyancy.
(2) Coatings and building materials
Thermal insulation coatings: Reduce building energy consumption (such as building exterior walls and pipeline insulation).
Matting agent: Adjust the gloss of coatings (such as matte paint).
(3) Petroleum industry
Low-density cement: Used for cementing oil and gas wells to prevent formation rupture.
Drilling fluid additives: Reduce density and improve drilling efficiency.
(4) Other fields
3D printing: Improve material fluidity and lightweight.
Cosmetics: Used as a softener to enhance skin feel.
4. Advantages and Challenges
(1) Advantages
✔ Ultra-light: The density is only 1/10 of that of solid glass beads.
✔ Heat and sound insulation: The hollow air layer effectively blocks heat conduction and sound waves.
✔ Good fluidity: The spherical structure improves the material processing performance.
