Magnesium oxide comprehensively improves the performance of road reflective glass beads by enhancing the refractive index, strengthening mechanical strength, optimizing thermal stability, and inhibiting crystallization.
1. Enhancing the Refractive Index of Glass Beads
The core performance of road reflective glass beads is their refractive index, which directly determines their reflective effect.
Magnesium oxide (MgO) is a high refractive index oxide, and its addition can increase the average refractive index of the glass matrix.
In typical formulations, magnesium oxide combines with silicon dioxide (SiO₂) to adjust the density of the glass network, resulting in stronger refraction and reflection of light within the glass beads.
2. Improving the Thermal Stability and Crack Resistance of Glass Beads
As a network intermediate, magnesium oxide can alleviate thermal expansion stress within the glass matrix.
Glass beads undergo drastic temperature changes during the melting and application processes. The addition of magnesium oxide can improve the thermal stability of the glass and reduce the generation of internal stress and surface cracks.
3. Optimizing the Mechanical Strength of Glass Beads
Magnesium oxide can improve the microstructure of glass beads (such as increasing the density of the glass network), thereby enhancing compressive strength and abrasion resistance.
This allows the glass beads to maintain their integrity under long-term vehicle rolling and climate changes, making them less prone to breakage or wear.
4. Lowering Melting Temperature and Improving Beading Rate
The addition of an appropriate amount of magnesium oxide can lower the melting temperature of the glass system, making the melting process easier to control and improving the beading efficiency and the roundness of the beads.
This is crucial in large-scale production, helping to reduce energy consumption and improve production consistency.
5. Adjusting the Surface Properties of Glass Beads (Hydrophilicity/Corrosion Resistance)
The alkaline oxide structure formed by magnesium oxide in the glass can enhance the affinity of the glass beads for water, allowing the bead surface to maintain a certain reflective effect even in humid conditions.
At the same time, the presence of magnesium oxide can also improve the chemical corrosion resistance of glass beads, especially against harsh environments such as acid rain and salt spray.
6. Reducing the Crystallization Tendency in Glass Beads and Maintaining Transparency
Excessive SiO₂ and certain alkaline oxides may cause the glass to form microcrystals during cooling, affecting transparency.
The introduction of magnesium oxide helps to inhibit excessive crystallization, maintaining a homogeneous and crystal-free transparent structure inside the glass beads, thereby ensuring efficient light transmission and reflection.