In today’s digital age, mobile phone screens are not just touch interfaces—they are engineered marvels. Behind the glossy surface of a smartphone lies a carefully developed glass composition that balances strength, clarity, and durability. One of the often-overlooked yet crucial ingredients in this process is magnesium oxide (MgO).
As an alkaline earth metal oxide, magnesium oxide is widely used as a raw material additive in advanced glass formulations, including high-end aluminosilicate glasses such as Corning’s Gorilla Glass and Schott’s Xensation. These types of glass are known for their exceptional drop resistance, optical clarity, and chemical durability—features that magnesium oxide directly contributes to.
In this blog, we’ll explore how magnesium oxide is used in the glass manufacturing process, particularly for mobile phone cover glass, and discuss the multi-dimensional benefits it brings—from chemical strengthening to thermal stability.
Application
Magnesium oxide is typically added during the glass batch formulation process, where it is combined with other raw materials like silica (SiO₂), alumina (Al₂O₃), sodium oxide (Na₂O), and potassium oxide (K₂O). When melted at high temperatures (above 1,500°C), these materials form a non-crystalline glass network.
In the context of mobile phone glass, magnesium oxide plays a functional role in modifying the glass structure. Its moderate ionic radius—larger than sodium but smaller than potassium—makes it uniquely suited to interact with the glass matrix. It can bridge between different network-forming ions, improve processing characteristics, and enhance the mechanical properties of the final product.
While the exact content of magnesium oxide in commercial glass compositions is often proprietary, it typically ranges from 1–5% by weight, striking a balance between performance enhancement and compositional stability.
Benefits of Using Magnesium Oxide
Optimize Chemical Strengthening Performance
One of the key features of modern mobile phone glass is chemical strengthening, which involves an ion exchange process where smaller sodium ions in the glass are replaced by larger potassium ions. This creates a surface layer under compressive stress, improving the strength of the glass.
Magnesium oxide can optimize this process by:
- Enhancing the mobility of exchangeable ions.
- Modifying the glass network to increase ion exchange depth.
- Potentially reducing stress relaxation, allowing the compressive stress layer to remain stable over time.
This contributes to a more robust and long-lasting protective layer, making the glass less prone to cracking or chipping.
Improve Impact/Drop Resistance
Magnesium oxide contributes to deeper compressive stress layers, which are essential for preventing crack propagation when a phone is dropped. Even if a surface flaw or scratch exists, the underlying compressive zone resists further damage.
This property is crucial for mobile devices, which are frequently subjected to drops and impacts in daily use. The inclusion of MgO helps the glass absorb and redistribute mechanical energy, reducing the likelihood of catastrophic failure.
Improve Scratch/Wear Resistance
While drop resistance is about absorbing impact, scratch resistance is about surface hardness. Magnesium oxide, by adjusting the microstructure and hardness of the glass, helps in:
- Increasing surface durability.
- Reducing micro-abrasions from keys, coins, or other hard objects.
This results in longer-lasting clarity and touch sensitivity, which are critical for user experience.
Enhance Thermal Stability and Reduce Thermal Expansion Coefficient
Smartphones generate heat during use—whether it’s from gaming, charging, or multitasking. Glass must withstand thermal fluctuations without cracking or warping.
Magnesium oxide plays a key role in:
- Reducing the thermal expansion coefficient of the glass.
- Improving thermal shock resistance.
- Minimizing deformation under fluctuating temperatures.
By enhancing thermal stability, MgO ensures the integrity of the glass during real-world usage conditions.
Improve Melting and Processing Performance
From a manufacturing perspective, magnesium oxide also delivers economic and technical advantages:
- Lowers melting point: This can reduce energy consumption during the glass production process.
- Improves melt fluidity: Ensures smoother flow during casting and molding.
- Reduces defects: Helps limit the formation of bubbles, inclusions, and undissolved particles, enhancing yield and consistency.
This is especially valuable for large-scale, high-precision production lines used in mobile phone glass manufacturing.
Enhance Chemical Durability
Smartphones encounter various environmental exposures—sweat, rain, oils, and cleaning agents. Magnesium oxide enhances the chemical durability of the glass by:
- Strengthening the glass network against alkali leaching.
- Improving resistance to water and acidic environments.
- Preserving the structural integrity and performance over time.
This contributes to a longer lifespan and better surface quality, which are key for premium mobile devices.
Maintain High Optical Properties
Optical clarity is non-negotiable for mobile screens. Magnesium oxide supports this by:
- Maintaining high light transmittance.
- Avoiding coloration or haziness that can arise from other additives.
- Minimizing internal defects like striae or crystallization.
MgO ensures that while mechanical and thermal properties are improved, optical performance remains uncompromised—a critical factor for high-resolution displays and user satisfaction.
Conclusion
Magnesium oxide may appear as a minor component in the complex formulation of mobile phone glass, but its impact is anything but small. From chemical strengthening and drop resistance to thermal stability and optical clarity, MgO contributes to almost every performance metric that defines high-end smartphone screens.
As a leading magnesium oxide manufacturer, we provide consistently pure, customizable MgO products tailored to meet the demanding requirements of the glass industry. Whether you’re developing next-gen cover glass or optimizing current production, we have the experience, technical support, and product quality you can rely on.
Looking for a reliable magnesium oxide supplier for your glass manufacturing needs?
Contact us now to speak with our technical team and explore how our high-performance MgO can support your innovation.
FAQs
How much magnesium oxide is typically used in mobile phone glass?
The typical content of magnesium oxide in aluminosilicate glass formulations ranges from 1–5% by weight, depending on the desired properties. The exact formula is usually proprietary to each manufacturer.
Can magnesium oxide improve both strength and clarity in glass?
Yes. Magnesium oxide enhances mechanical properties like strength and thermal stability without compromising optical clarity, making it ideal for use in high-transparency applications like mobile phone screens.
Is magnesium oxide used in all types of smartphone glass?
While not universal, MgO is a common additive in high-performance aluminosilicate glasses, such as those used in Gorilla Glass and Xensation, due to its well-rounded property enhancements.
