Crystallized Glass Compressive Stress Layer
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Solution Overview
Problem
Conventional crystallized glass materials used in harsh environments, such as smartphone covers and vehicle windshields, lack sufficient surface hardness and compressive stress values, making them prone to cracking and inadequate for demanding applications.
Innovation Solution
A crystallized glass article with a compressive stress layer, comprising α-cristobalite and α-cristobalite solid solution as the main crystal phase, with specific oxide component ratios and a surface compressive stress value of 600 MPa or more, achieved through chemical strengthening, heat treatment, or ion implantation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chemical strengthening is applied to conventional crystallized glass, then compressive stress is introduced to suppress crack growth, but the surface hardness and mechanical strength remain insufficient for harsh environments
Solution Approach 1:
The patent applies parameter changes by optimizing the chemical composition ratios (SiO2: 50-75%, Li2O: 3-10%, Al2O3: 5-15%, with Al2O3+ZrO2 total: 10-20%) and controlling heat treatment parameters (temperature: 600-800°C, time: 1-10 hours) to achieve both high compressive stress (≥600 MPa) and high surface hardness, resolving the contradiction between strength and reliability
Solution Approach 2:
The patent uses composite materials by creating a crystallized glass with multiple crystal phases (α-cristobalite and α-cristobalite solid solution) combined with specific glass matrix composition, which provides both the compressive stress needed for crack suppression and the surface hardness required for harsh environment durability
2Reliability
If conventional crystallized glass is used in harsh environments, then it provides basic protection, but it lacks sufficient surface hardness and is prone to cracking
Solution Approach 1:
The patent changes the chemical composition parameters within specific ranges (SiO2: 50-75%, Li2O: 3-10%, Al2O3: 5-15%, ZrO2: 0-10%, with Al2O3+ZrO2 total: 10-20%) to optimize both surface hardness and environmental durability simultaneously, eliminating the need to trade off between these properties
3Strength
If compressive stress layer is formed through ion implantation, then surface hardness is improved, but the process complexity and manufacturing difficulty increase
Solution Approach 1:
The patent provides alternative parameter changes through chemical strengthening or heat treatment methods that achieve the same surface hardness improvement without ion implantation complexity, allowing manufacturers to choose simpler processes while meeting performance 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 resulting inorganic composition article exhibits enhanced mechanical strength and surface hardness, effectively suppressing crack growth and improving durability for use in harsh environments.
Implementation Method 1
When an alkaline component existing in a surface layer of glass is subject to exchange reaction with an alkaline component with a larger ionic radius to form a compressive stress layer on the surface, it is possible to suppress the growth of cracks and increase the mechanical strength
Implementation Method 2
When an alkaline component existing in a surface layer of glass is subject to exchange reaction with an alkaline component with a larger ionic radius
Data Source
AI summary
To provide an inorganic composition article containing at least one kind selected from α-cristobalite and α-cristobalite solid solution as a main crystal phase, in which by mass% in terms of oxide, a content of a SiO2 component is 50.0% to 75.0%, a content of a Li2O component is 3.0% to 10.0%, a content of an Al2O3 component is 5.0% or more and less than 15.0%, and a total content of the Al2O3 component and a ZrO2 component is 10.0% or more, and a surface compressive stress value is 600 MPa or more.