Aluminosilicate Glass Substrate Clarification via Non-Toxic Fining Agents
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Solution Overview
Problem
Conventional methods for removing gas bubbles from glass substrates for information recording media, such as magnetic disks, often require toxic fining agents like As2O3 and Sb2O3, or complex processes involving decompression, which are environmentally and health-wise undesirable, and can alter the glass composition.
Innovation Solution
A glass substrate made of aluminosilicate glass with specific compositions (60-75% SiO2, 5-18% Al2O3, 3-10% Li2O, 3-15% Na2O, and 0.5-8% ZrO2) using non-toxic fining agents like SO3, F, Cl, Br, or I, at a molar ratio of 0.02-0.20 with Al2O3, allowing for effective clarification of gas bubbles without As or Sb, and enhanced chemical strengthening through ion exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If As2O3 and Sb2O3 are used as fining agents to remove gas bubbles, then gas bubble removal effectiveness is improved, but environmental and health safety deteriorates due to toxicity
Solution Approach 1:
The patent extracts and removes the harmful As2O3 and Sb2O3 fining agents from the glass composition, replacing them with non-toxic alternatives while maintaining gas bubble removal effectiveness through the specified fining agent system with molar ratio control
Solution Approach 2:
The patent changes the chemical composition parameters by specifying a molar ratio of fining agent to Al2O3 within 0.02 to 0.20, and controlling total fining agent content at 1% by mass or less, thereby achieving effective gas bubble removal without toxic substances
2Object-affected harmful factors
If decompression method is used to remove gas bubbles, then toxic fining agents are eliminated, but process complexity and equipment requirements increase
Solution Approach 1:
The patent enables the glass composition itself to perform the gas bubble removal function through the carefully controlled fining agent system, eliminating the need for external decompression apparatus and making the glass self-sufficient in its clarification process
Solution Approach 2:
The patent changes the approach from physical decompression to chemical clarification by controlling the molar ratio of fining agent to Al2O3 within 0.02 to 0.20, thereby achieving gas bubble removal through chemical reactions rather than mechanical decompression
3Manufacturing precision
If decompression is applied to remove gas bubbles, then gas bubble removal is achieved, but glass component volatilization increases
Solution Approach 1:
The patent converts the potential harm of fining agent usage into a benefit by selecting non-toxic fining agents that effectively remove gas bubbles without causing glass component volatilization, thereby turning a previously harmful process into a beneficial one
Solution Approach 2:
The patent changes the process parameters by controlling the total fining agent content at 1% by mass or less and specifying the molar ratio range, thereby achieving gas bubble removal without the excessive volatilization caused by decompression methods
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
This approach effectively removes gas bubbles from the glass substrates without using toxic elements, maintaining the glass's mechanical properties and devitrification resistance, and can be produced using standard processes without specialized equipment.
Implementation Method 1
clarification reaction due to the valence change of the polyvalent elements can effectively function. Therefore, without As (arsenic) or Sb (antimony) element, a glass substrate for an information recording medium with sufficiently removed gas bubbles can be obtained
Implementation Method 2
glass substrates formed of aluminosilicate glass capable of strengthening substrates by chemical strengthening treatment by ion exchange, because of their enhanced impact resistance and vibration resistance
Data Source
AI summary
A glass substrate for information recording medium, said glass substrate being composed of an aluminosilicate glass containing 60-75% by mass of SiO2, 5-18% by mass of Al2O3, 3-10% by mass of Li2O, 3-15% by mass of Na2O and 0.5-8% by mass of ZrO2 relative to the entire glass components. The glass substrate for information recording medium contains neither As (arsenic) nor Sb (antimony), while containing at least one substance selected from the group consisting of SO3 (sulfurous acid), F (fluorine), Cl (chlorine), Br (bromine) and I (iodine), as a refining agent. The molar ratio of the total amount of the refining agent to the amount of Al2O3 is within the range of 0.02-0.20.