Messi Biology states that magnesium oxide comprehensively improves the performance of road reflective glass beads by increasing their refractive index, enhancing mechanical strength, optimizing thermal stability, and inhibiting crystallization.
1. Increasing 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, enabling light to produce stronger refraction and reflection effects within the glass beads.
2. Improving the thermal stability and crack resistance of glass beads
As a network modifier, magnesium oxide can alleviate thermal expansion stress in the glass matrix.
Glass beads undergo drastic temperature changes during melting and use. The addition of magnesium oxide can improve the thermal stability of the glass, reducing the generation of internal stress and surface cracks.
3. Optimizing the mechanical strength of glass beads
Magnesium oxide can improve the microstructure of the glass beads (such as increasing the denseness of the glass network), thereby enhancing their compressive strength and wear resistance.
This allows the glass beads to maintain their integrity and resist breaking or wearing down under long-term vehicle pressure and climate change.
4. Lowering the melting temperature and improving the bead formation 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 efficiency of bead formation 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 the glass beads, especially against acid rain, salt spray, and other harsh environments.
6. Reducing the tendency of crystallization in glass beads and maintaining transparency
Excessive SiO₂ and certain alkaline oxides can cause the glass to form microcrystals upon cooling, affecting its transparency.
The introduction of magnesium oxide helps to inhibit excessive crystallization, maintaining a uniform, non-crystalline, transparent structure inside the glass beads, thereby ensuring the efficient transmission and reflection of light.