Glass-ceramic and process for the production thereof
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Solution Overview
Problem
Existing glass ceramics with vanadium oxide for coloring have high sensitivity to vanadium content variations, making it challenging to achieve consistent transmission and color in the visible spectral range, especially when aiming for higher transmission values.
Innovation Solution
Incorporating a high content of iron oxide (>0.1% by weight) in lithium aluminosilicate glass ceramics, which interacts with vanadium oxide to reduce absorption, allowing for higher transmission (>2.5%) and more precise control over color and transmission by adjusting iron oxide content, while maintaining low thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If vanadium oxide is added as a coloring component to achieve desired color, then coloration is achieved, but transmission in the visible spectral range is reduced and color distortion increases
Solution Approach 1:
The patent changes the chemical composition parameters by adding iron oxide (Fe2O3) at more than 0.1% by weight in combination with vanadium oxide (V2O5) at 0.005-0.05% by weight. This parameter change modifies the optical properties of the glass-ceramic, reducing the harmful coloring effect of vanadium oxide while maintaining desired coloration, thereby improving light transmission and reducing color distortion.
Solution Approach 2:
The patent creates a composite coloring system by combining vanadium oxide and iron oxide in specific proportions within the lithium aluminosilicate glass-ceramic matrix. This composite approach allows the iron oxide to counterbalance the strong coloring effect of vanadium oxide, achieving a balance between coloration and light transmission that neither oxide could achieve alone.
2Object-generated harmful factors
If vanadium oxide content is increased to achieve desired color tone, then coloration is improved, but manufacturing precision is reduced due to high sensitivity to content variations
Solution Approach 1:
Iron oxide acts as an intermediary substance that mediates the relationship between vanadium oxide content and final color tone. By introducing this intermediary, the system becomes less sensitive to variations in vanadium oxide content, as the iron oxide provides a stabilizing effect on the overall coloration, thereby improving manufacturing precision.
Solution Approach 2:
The patent introduces a new compositional parameter (iron oxide content >0.1% by weight) that changes the system's sensitivity characteristics. This parameter change creates a more robust formulation where color tone is less dependent on precise vanadium oxide dosage, reducing manufacturing precision requirements.
3Illumination intensity
If iron oxide content is increased to reduce vanadium oxide absorption, then transmission is improved, but coloration effect may be reduced
Solution Approach 1:
The patent optimizes the parameter balance between iron oxide (>0.1% by weight) and vanadium oxide (0.005-0.05% by weight) to achieve a synergistic effect. The iron oxide content is set high enough to reduce vanadium oxide absorption and improve transmission, while the vanadium oxide content is maintained at a level sufficient to provide desired coloration, creating an optimal balance between these opposing requirements.
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 high iron oxide content in lithium aluminosilicate glass ceramics enhances transmission in the visible spectral range, providing a more stable and precise color tone with reduced sensitivity to vanadium oxide variations, suitable for applications like hobs and fireplace screens.
Implementation Method 1
the absorption by the vanadium oxide is weakened. Specifically, the invention provides for a lithium aluminosilicate glass-ceramic article according to claim 1, particularly in the form of a glass-ceramic plate, which comprises vanadium oxide as a coloring component in a proportion of at least 0.005, preferably at least 0.01, and particularly preferably up to 0.05 percent by weight, wherein the tin oxide content is less than 0.5 percent by weight, and wherein the glass-ceramic further comprises iron oxide in a proportion of more than 0.1 percent by weight, wherein the iron oxide content is at least as high as or higher than the vanadium oxide content, and wherein the light transmission of the glass-ceramic article in the visible spectral range when illuminated perpendicular to the surface of the glass-ceramic article is more than 2.5 percent.
Data Source
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AI summary
The invention provides a glass-ceramic in the production of which a reliable coloration having a defined transmission is ensured. The invention is based on the fact that a high content of iron oxide, which itself intrinsically imparts a strong colour, of more than 0.1% by weight does not reduce the transmission further but instead interacts with vanadium oxide so as to decrease the absorption caused by vanadium oxide.