High-Rigidity Glass Substrate Composition for HDD Vibration Resistance
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Solution Overview
Problem
Magnetic recording medium substrates made of aluminum alloy are susceptible to deformation and vibration during high-speed rotation, which can lead to head crashes and limit the recording capacity of hard disk drives.
Innovation Solution
Developing a high-rigidity glass substrate for magnetic recording media with specific compositions of B2O3, Na2O, CaO, MgO, and other oxides to enhance specific elastic modulus and thermal stability, reducing vibration and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the glass substrate is reduced to reduce the thickness of the magnetic recording medium, then the recording capacity of HDD is improved, but the rigidity of the substrate deteriorates and vibration increases
Solution Approach 1:
The patent changes the chemical composition parameters of the glass substrate by controlling the content ranges of B2O3 (0.1-2.0 mol%), Na2O (1.0-6.0 mol%), CaO (0-1.0 mol%), and MgO (14.0 mol% or more). This composition optimization increases the specific elastic modulus to 35.0 MNm/kg or more, enabling thin substrates to maintain high rigidity and suppress vibration while reducing thickness for higher recording capacity.
2Quantity of substance
If the thickness of the glass substrate is reduced to reduce the thickness of the magnetic recording medium, then the recording capacity of HDD is improved, but the susceptibility to vibration during high-speed rotation increases
Solution Approach 1:
The patent optimizes glass composition parameters (B2O3: 0.1-2.0 mol%, Na2O: 1.0-6.0 mol%, CaO: 0-1.0 mol%, MgO: ≥14.0 mol%) to achieve a specific elastic modulus of 35.0 MNm/kg or more. This enables thin substrates to maintain high vibration resistance during high-speed rotation, preventing head crashes while enabling increased recording capacity through reduced substrate thickness.
3Ease of manufacture
If aluminum alloy is used as the substrate material, then the manufacturing cost is reduced, but the susceptibility to deformation during high-speed rotation increases
Solution Approach 1:
The patent develops a specialized glass composite material with optimized composition (B2O3: 0.1-2.0 mol%, Na2O: 1.0-6.0 mol%, CaO: 0-1.0 mol%, MgO: ≥14.0 mol%) that achieves superior dimensional stability and rigidity. This glass substrate eliminates the deformation problems of aluminum alloys during high-speed rotation while maintaining manufacturability through established glass processing techniques.
Data Source
AI summary
Provided is a glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing device, the glass being an amorphous glass, wherein a B2O3 content is 0.10 mol % or more and 2.00 mol % or less, a Na2O content is 1.00 mol % or more and 6.00 mol % or less, a CaO content is 0 mol % or more and 1.00 mol % or less, and a MgO content is 14.00 mol % or more.