Boron Products / Boron Oxide
B₂O₃. ≥99.0% purity. Anhydrous. Zero sodium. Zero water. The precision boron input.
Anhydrous boron oxide is the only commercial boron product that delivers a sodium-free, water-free boron input. This makes it the required grade in optical glass formulations where sodium alters refractive index, in electronic ceramics (MLCC) where sodium affects dielectric properties, and in specialty glass compositions requiring independent Na₂O and B₂O₃ control. Highly hygroscopic — sealed moisture-proof packaging and dry storage mandatory.
Why boron oxide when borax cannot be used
The three applications where sodium contamination is disqualifying
Optical & Display Glass
In optical glass (crown glass, flint glass) and flat panel display glass substrates, the refractive index is determined by precise oxide composition ratios. Sodium introduced via borax shifts the Na₂O/B₂O₃ ratio in the glass and changes both the refractive index and the CTE unpredictably. Boron oxide allows the glass formulator to add B₂O₃ independently — without inadvertently adding Na₂O — enabling specification-accurate composition in every melt. Na₂O max 0.1% is the critical parameter.
Na₂O max 0.1% specification
Electronic Ceramics (MLCC)
Multilayer ceramic capacitors (MLCCs) use boron oxide as a sintering aid and glass phase modifier in the dielectric ceramic formulation. Sodium contamination at any level above 50 ppm degrades the dielectric constant and insulation resistance of the finished capacitor — potentially failing the component at voltage. Boron oxide (Na₂O ≤0.1%) is the only commercially available boron source that meets this specification. It also acts as a flux in BaTiO₃ ceramic sintering, reducing firing temperature by 50–100°C.
Electronic ceramic grade
Optical Fiber Manufacturing
In modified chemical vapour deposition (MCVD) and outside vapour deposition (OVD) processes for optical fiber preform manufacture, boron oxide vapour (from gaseous B₂O₃ or BCl₃) is deposited as a cladding dopant to reduce the refractive index of the silica cladding relative to the germanium-doped core. The sodium-free, water-free specification is essential — both Na and OH groups create absorption bands in the fiber that increase signal loss at communication wavelengths (1310nm, 1550nm).
Fiber optic CVD/OVD grade
| Parameter | Test method | Standard grade | High-purity grade | Critical parameter — why it matters |
|---|---|---|---|---|
| B₂O₃ purity |
Titrimetric · Karl Fischer
|
≥99.0%
|
≥99.5%
|
Basis of all formulation calculations — must be verified against stated assay on every COA |
| Na₂O content |
ICP-OES
|
≤0.1%
|
≤0.05%
|
CRITICAL: sodium disqualifies boron oxide for optical glass, MLCC, and fiber optic applications. Must be confirmed analytically.
|
| Iron (Fe) |
ICP-OES
|
≤15 ppm | ≤5 ppm | Glass colour impurity — lower Fe required for optical and display glass applications |
| Water (H₂O) |
Karl Fischer titration
|
≤0.5% | ≤0.2% |
CRITICAL: boron oxide is highly hygroscopic — absorbs atmospheric moisture rapidly. Open bags must be resealed immediately and product used within 24 hours of opening.
|
| Appearance |
—
|
White to off-white glassy lumps or powder | White glassy powder | Vitreous texture at room temperature — softens above 450°C (no sharp melting point) |
| Packaging |
—
|
25 kg moisture-proof PE-sealed bags · Outer PP woven · Inert atmosphere optional | 25 kg hermetically sealed aluminium foil bags | Moisture-proof packaging mandatory — exposure to humid air converts B₂O₃ to H₃BO₃ within hours, reducing purity and altering product chemistry |
Boron oxide — critical parameters
≥99.0%
B₂O₃ purity — highest boron concentration of any Eti Maden commercial product
Na₂O ≤0.1%
Sodium-free specification — the defining advantage over all borax grades
Hygroscopic
Moisture-proof sealed packaging mandatory — absorbs atmospheric moisture rapidly
4 hrs
Quotation response — specify Na₂O requirement and Fe specification for your application
Specify Na₂O max, Fe max, and application. We confirm the correct grade and packaging.
Standard grade (Na₂O ≤0.1%) for most specialty glass and ceramic applications. High-purity grade (Na₂O ≤0.05%, Fe ≤5 ppm) for optical glass and fiber. Moisture-proof packaging mandatory — confirm storage conditions before ordering.
Boron oxide procurement