Transparent Vitroceramic Plate Composition for Low-Haze Heat Resistance
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Solution Overview
Problem
Conventional glass-ceramics used in cooking devices and fireplace inserts often have low light transmission and scattering issues due to the use of arsenic and antimony oxides, which are toxic and costly, and neodymium oxide can introduce unwanted colors and reduce transparency.
Innovation Solution
A transparent, colorless, and non-scattering lithium aluminosilicate glass-ceramic plate with a specific chemical composition excluding arsenic, antimony, and neodymium oxides, optimized with SiO2, Al2O3, Li2O, Na2O, CaO, BaO, MgO, ZnO, TiO2, and ZrO2 to achieve high light transmission and low thermal expansion, preventing yellow coloration and scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If arsenic or antimony oxides are used as refining agents, then the glass can be refined effectively, but the glass-ceramic becomes toxic and costly
Solution Approach 1:
The patent removes arsenic and antimony oxides from the glass composition entirely, replacing them with non-toxic alternatives. This extraction of harmful substances while maintaining refining functionality resolves the contradiction between effective refining and toxicity elimination.
Solution Approach 2:
The patent substitutes expensive and toxic refining agents with cheaper, non-toxic metal oxides such as zinc oxide, bismuth oxide, or tin oxide. This replacement achieves both cost reduction and toxicity elimination while maintaining refining effectiveness.
2Ease of manufacture
If neodymium oxide is used to discolor the glass-ceramic, then the yellow color is reduced, but the light transmission decreases and the cost increases
Solution Approach 1:
The patent eliminates neodymium oxide from the composition, removing the substance that causes both the yellow color and the light transmission reduction. Instead, it uses alternative discoloration methods that do not compromise optical properties.
Solution Approach 2:
The patent controls the glass composition parameters, specifically limiting yellowing through precise control of metal oxide ratios and processing conditions, rather than using strong discoloring agents like neodymium oxide that would reduce light transmission.
3Ease of manufacture
If titanium oxide and zirconium oxide content is reduced below 3.8%, then the cost decreases, but uncontrolled crystal growth occurs causing haze
Solution Approach 1:
The patent optimizes the combined content of titanium oxide and zirconium oxide within specific ranges (TiO2: 0.5-2.0%, ZrO2: 0.5-3.0%) to achieve both cost reduction and controlled crystal growth. This parameter optimization prevents haze while maintaining affordability.
Solution Approach 2:
The patent uses a composite approach by combining multiple metal oxides (titanium oxide, zirconium oxide, zinc oxide, bismuth oxide) that work synergistically to control crystal nucleation and growth, achieving better performance than any single oxide alone at lower concentrations.
4Illumination intensity
If the glass-ceramic is made transparent with high light transmission, then visibility is improved, but the use of certain additives becomes necessary that may cause scattering
Solution Approach 1:
The patent precisely controls the composition parameters of metal oxides and the crystallization process parameters to achieve transparent glass-ceramic with high light transmission (≥70%) and low scattering (haze ≤3%). This dual parameter control resolves the contradiction between transparency and scattering.
Solution Approach 2:
The patent creates localized control of crystal distribution and size within the glass matrix, ensuring that crystals are uniformly distributed and sized to minimize light scattering while maintaining overall transparency. This local quality control achieves both high transmission and low haze.
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 solution provides a glass-ceramic with a light transmission factor of at least 75%, minimal yellow tint, and excellent thermal shock resistance, ensuring clear visibility and durability in high-temperature applications.
Implementation Method 1
crystals of β-quartz or β-spodumene structure (depending on the ceramization temperature), which generally have the distinctive feature of possessing negative thermal expansion coefficients, so much so that the glass-ceramic possesses in the end a very low thermal expansion coefficient
Implementation Method 2
plates that have high thermomechanical strength, in particular an excellent thermal shock resistance
Implementation Method 3
transparent, colorless and non-scattering glass-ceramic plates... the light transmission factor, within the meaning of the NF EN 410 standard, is at least 70%
Implementation Method 4
non-scattering... the haze, within the meaning of the ASTM D1003-00 standard, is at most 3%... The haze corresponds to the ratio between the diffuse light transmission and the total light transmission
Implementation Method 5
resistance to corrosive atmospheres at high temperature
Data Source
AI summary
A transparent, colorless and non-scattering glass-ceramic plate of lithium aluminosilicate type and containing crystals of β-quartz structure, the chemical composition of which does not contain oxides of arsenic, of antimony and of neodymium, and includes the following constituents within the limits defined below, expressed as weight percentages: SiO2 55-75%; Al2O3 12-25%; Li2O 2-5%; Na2O+K2O 0-<2%; Li2O+Na2O+K2O 0-<7%; CaO 0.3-5%; MgO 0-5%; SrO 0-5%; BaO 0.5-10%; CaO+BaO >1%; ZnO 0-5%; TiO2 ≤1.9%; ZrO2 ≤3%; TiO2+ZrO2 >3.80%; SnO2 ≥0.1%; SnO2/(SnO2+ZrO2+TiO2)<0.1.