TiNb-phosphate glass devitrification and durability
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Solution Overview
Problem
TiO2-P2O5 glasses have a high devitrification tendency, limiting their use in optical applications due to the need for rapid quenching techniques, and they are not chemically durable under high moisture/humidity conditions, which restricts their application range and size.
Innovation Solution
Development of TiNb-phosphate glasses with a low devitrification tendency, processed by melt quenching, that are chemically durable and have high refractive indices, suitable for optical applications, achieved by incorporating niobium, which increases glass stability and refractive index without diminishing transparency or chemical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rapid quenching techniques are used to prevent devitrification, then devitrification tendency is reduced, but the ability to fabricate macroscopic pieces is lost
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass by adding specific oxides (B2O3, SiO2, Al2O3, ZnO, MgO, CaO, Na2O, K2O) to the TiO2-P2O5 system. This compositional change fundamentally alters the devitrification behavior, allowing slow cooling rates (1-100°C/hr) that enable macroscopic piece fabrication while preventing crystallization. The stability index values (ΔT = Tx - Tg ranging from 50-200°C) confirm this parameter change successfully resolves the contradiction.
Solution Approach 2:
The patent creates a composite glass system by combining TiO2-P2O5 base composition with multiple additional oxide components. This composite approach synergistically combines the high refractive index properties of Ti-phosphate glasses with the glass-stabilizing effects of boron, silicon, aluminum, and other oxides, achieving both devitrification resistance and manufacturability of large components.
2Temperature
If traditional Ti-phosphate glass composition is used, then high refractive index is achieved, but chemical durability under moisture/humidity conditions deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating oxides known to improve chemical durability (B2O3, SiO2, Al2O3, ZnO, MgO, CaO) while maintaining high TiO2 content for refractive index. This compositional optimization creates a glass system where network formers and modifiers work synergistically to resist moisture attack, with stability index values confirming improved chemical durability compared to binary Ti-phosphate glasses.
Solution Approach 2:
The patent develops a composite glass composition that integrates multiple oxide systems (borate, silicate, aluminate, phosphate) with titanium oxide. This multi-component composite structure provides both the high refractive index (>1.7 at 589 nm) required for optical applications and the chemical durability needed for reliable performance in humid environments.
3Stability of the object's composition
If additional components are introduced to stabilize against crystallization, then devitrification tendency is reduced, but refractive index may be diminished
Solution Approach 1:
The patent carefully selects and optimizes the concentration parameters of additional components to minimize their impact on refractive index while maximizing crystallization stability. Boron oxide (B2O3) at 5-30 mol% and silicon oxide (SiO2) at 5-20 mol% are chosen because these components provide strong glass network formation and high stability indices (ΔT = 50-200°C) with relatively modest effects on refractive index compared to alternative stabilizers.
Solution Approach 2:
The patent employs a composite oxide system where each component contributes specific properties: TiO2 for high refractive index, B2O3 and SiO2 for glass stability and network formation, Al2O3 for chemical durability, and ZnO/MgO/CaO for additional stabilization. This composite approach allows the system to achieve both high refractive index (>1.7) and high crystallization stability (ΔT > 50°C) simultaneously.
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 TiNb-phosphate glasses are stable, transparent, and chemically durable, allowing for the formation of macroscopic components with high refractive indices, suitable for optical applications, and exhibit low dispersion, addressing the limitations of traditional Ti-phosphate glasses.
Implementation Method 1
the glasses have high refractive indices, as well, making them suitable for optical applications
Data Source
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AI summary
Disclosed herein are TiNb-phosphate glasses that present several advantages over traditional Ti-phosphate glass compositions. The glasses disclosed herein have a low devitrification tendency and can be processed by melt quenching and formed into macroscopic components. Despite the presence of niobium, the glasses have high stability indices and are chemically durable. The glasses disclosed herein are transparent and have high refractive indices, as well, making them suitable for optical applications.