Lead-Free Glass Composition for Low-Temperature Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lead-free low-melting point glass compositions struggle to provide reliable adhesiveness and tight contactness at temperatures below 370°C, particularly in sealing and adhesion applications, due to high crystallization tendencies and compromised chemical stability.
Innovation Solution
A lead-free glass composition comprising vanadium oxide, tellurium oxide, alkali metal oxide, iron oxide, barium oxide, and tungsten oxide, with additional components like yttrium, lanthanum, and gallium oxides, optimized to achieve a softening point below 370°C, enhancing adhesiveness and chemical stability while minimizing crystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing lead-free low-melting point glass compositions are used, then the softening point is reduced, but adhesiveness and tight contactness deteriorate at temperatures below 370°C
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass by adjusting the ratios of V2O5 (20-40 mass%), TeO2 (25-45 mass%), R2O (5-30 mass%), Fe2O3 (1-10 mass%), BaO (5-20 mass%), and WO3 (1-15 mass%). This parameter optimization enables the glass to achieve both low softening point (≤370°C) and high adhesiveness, resolving the contradiction between temperature reduction and reliability maintenance.
Solution Approach 2:
The patent creates a composite glass system combining multiple oxide components with complementary functions: V2O5 and TeO2 provide low melting point, while BaO and WO3 enhance chemical stability and adhesiveness. The synergistic combination of these materials achieves both low processing temperature and high bonding reliability.
2Temperature
If existing lead-free low-melting point glass compositions are used, then the softening point is reduced, but chemical stability deteriorates
Solution Approach 1:
The patent optimizes the composition parameters by incorporating BaO (5-20 mass%) and WO3 (1-15 mass%) which enhance chemical stability, while balancing them with V2O5 and TeO2 to maintain low softening point. This parameter optimization resolves the contradiction between temperature reduction and stability maintenance.
Solution Approach 2:
The patent employs a composite oxide system where BaO and WO3 provide chemical stability and resistance to crystallization, while V2O5-TeO2 base provides low melting point. The composite structure achieves both low softening temperature and high chemical stability through synergistic material combination.
3Temperature
If existing lead-free low-melting point glass compositions are used, then the softening point is reduced, but crystallization tendency increases
Solution Approach 1:
The patent adjusts composition parameters to suppress crystallization by optimizing the ratio of network formers (TeO2, V2O5) to network modifiers (BaO, WO3, R2O). The specific composition range prevents crystal nucleation while maintaining low softening point, resolving the contradiction between temperature reduction and crystallization resistance.
Solution Approach 2:
The patent creates a composite glass system where multiple oxide components work synergistically to suppress crystallization. The combination of V2O5, TeO2, BaO, WO3, and Fe2O3 in specific proportions creates a homogeneous amorphous structure that resists crystallization while maintaining low softening temperature.
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 composition achieves excellent adhesiveness and tight contactness at temperatures as low as 370°C or lower, improving the reliability of sealing and adhesion while maintaining chemical stability and reducing thermal damage, thus enhancing the functionality and productivity of sealing structures.
Implementation Method 1
The PbO—B2O3 based low-melting point glass composition has a low softening point ranging from 350° C. to 400° C., and exhibits excellent softened fluidity at the temperature ranging from 400° C. to 450° C.
Implementation Method 2
Adhesiveness or tight contactness will be evaluated by judging whether or not leakage and exfoliation occur in the sealing part or the adhesion part
Data Source
AI summary
The lead-free glass composition contains vanadium oxide, tellurium oxide, alkali metal oxide, iron oxide, barium oxide, and tungsten oxide while containing substantially no phosphorus oxide, and further contains at least one of additional components including yttrium oxide, lanthanum oxide, cerium oxide, erbium oxide, ytterbium oxide, aluminum oxide, and gallium oxide. A content of the tellurium oxide is equal to or more than 25 mol %, and equal to or less than 43 mol % in terms of oxide TeO2. A content of the alkali metal oxide is equal to or more than 4 mol %, and equal to or less than 27 mol % in terms of oxide R2O (R: alkali metal element).