Alkaline Earth Phosphate Precipitations on Glass Surface
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Solution Overview
Problem
Existing glass production methods, such as the floating process, often result in surface damage during the lift-off operation due to mechanical stress, particularly on the lower contact side, which is exacerbated by high temperatures and adhesive properties of the glass, leading to scratches, chips, and reduced strength, especially in alkali-free or low-alkali glasses.
Innovation Solution
A glass composition with at least 0.3% by weight of alkaline earth oxides and 0.1 to 4% by weight of P2O5 is developed, featuring precipitations on the surface, preferably alkaline earth phosphate, with a mean size of 1 to 20 μm, that provide mechanical protection without affecting the glass's appearance or chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfur trioxide gassing is conducted to protect the glass surface, then resistance against mechanical stress is improved, but device complexity and additional processing steps are required
Solution Approach 1:
The glass composition itself provides the protective function through self-formed precipitations. The glass contains alkaline earth metal oxides (0.3-10% by weight) and P2O5 (0.1-4% by weight) that automatically form protective precipitations on the surface during the floating process, eliminating the need for external sulfur trioxide gassing equipment and post-processing purification steps
Solution Approach 2:
The invention changes the chemical composition parameters of the glass by incorporating specific amounts of alkaline earth metal oxides and P2O5. This compositional modification enables the glass to form protective precipitations in-situ during manufacturing, replacing complex external protective measures with intrinsic material properties
2Reliability
If sulfur trioxide gassing is conducted, then protection against mechanical stress is achieved, but additional processing steps and purification are required
Solution Approach 1:
The glass composition automatically forms protective precipitations during the floating process without requiring external intervention. The alkaline earth metal phosphates precipitate out during cooling and annealing, providing self-protection against mechanical stress from lift-out rollers without needing sulfur trioxide gassing or subsequent purification operations
3Reliability
If the glass surface is protected by external measures, then resistance against surface damage is improved, but the glass requires additional protective measures during storage and transport
Solution Approach 1:
The glass possesses inherent surface protection through precipitations formed during manufacturing. These precipitations remain on the glass surface throughout storage and transport, providing continuous protection without requiring external protective films, packaging, or handling precautions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The glass exhibits improved resistance to surface damage, allowing for effective protection against mechanical stress without the need for additional protective measures like sulfur trioxide gassing, and can be easily processed and stored without additional protection, maintaining the glass's visual and functional integrity.
Implementation Method 1
the glass has precipitations with a mean size of from 1 to 20 μm... Preferably, the precipitations are alkaline earth phosphate precipitations
Data Source
AI summary
A glass having excellent resistance against surface damages is provided. The glass includes a content of alkaline earth oxides of at least 0.3% by weight and of P2O5 of 0.1 to 4% by weight; the glass has at least one surface that has precipitations with a mean size of 1 to 20 μm. A method is further provided and includes melting a glass batch, yielding a glass melt, and casting the glass melt onto a float bath. The glass melt is maintained on the float bath at a temperature of above 1000° C. for at least 5 minutes, and yields glass. The glass has a content of alkaline earth oxides of at least 0.3% by weight and of P2O5 of 0.1 to 4% by weight, and the glass has at least one surface that has precipitations with a mean size of 1 to 20 μm.