Ni-P Coated Magnetic Disk Substrate for Vibration Damping
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Solution Overview
Problem
The reduction in thickness of magnetic-disk substrates to increase storage capacity leads to reduced rigidity and increased vibration, causing scratches, defects, and particles due to external impacts, which conventional substrates fail to effectively mitigate.
Innovation Solution
A magnetic disk substrate with a glass or aluminum alloy substrate main body and a continuous Ni-P alloy film covering the main surfaces, chamfered surfaces, and side wall surfaces, with a thickness ratio of the film to the substrate of 0.025 or more, to attenuate vibration and reduce contact with ramps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the magnetic-disk substrate is reduced to increase storage capacity, then the storage capacity is improved, but the rigidity of the substrate decreases and vibration increases
Solution Approach 1:
The patent applies composite materials by combining the substrate main body (glass or aluminum alloy) with a metal film layer (Ni, Ni-P, or Ni-Fe-P alloy) to create a composite structure. This composite construction allows the substrate to achieve both reduced thickness for increased storage capacity and maintained rigidity through the reinforcing metal film, resolving the contradiction between thinning the substrate and preserving structural strength.
2Quantity of substance
If the thickness of the magnetic-disk substrate is reduced, then the storage capacity is improved, but vibration increases causing scratches and defects
Solution Approach 1:
The metal film layer in the composite structure serves as a vibration-damping component that suppresses vibration-induced scratches and defects. This allows the substrate to be thinned for increased storage capacity while the metal film prevents harmful vibrations from causing surface defects.
Solution Approach 2:
The patent specifies particular parameter ranges for the metal film thickness (0.02 to 0.50 μm) and substrate thickness (0.635 mm or less) to optimize the balance between vibration suppression and storage capacity. By carefully controlling these parameters, the substrate can be thinned while maintaining sufficient rigidity to prevent vibration-induced defects.
3Quantity of substance
If the thickness of the magnetic-disk substrate is reduced, then the storage capacity is improved, but the substrate becomes more susceptible to damage from external impacts
Solution Approach 1:
The metal film layer acts as a protective reinforcement that enhances the substrate's resistance to external impacts. This composite structure allows the substrate to be thinned for increased storage capacity while the metal film provides additional strength and reliability against impact damage.
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 substrate effectively suppresses vibration-induced scratches and defects, maintaining disk integrity and reducing particle formation, even at reduced thicknesses, enhancing storage capacity without increasing power consumption or material costs.
Implementation Method 1
The film is an alloy film containing Ni and P... effectively suppresses vibration-induced scratches and defects... vibration caused by an external impact in this manner attenuates over time
Data Source
AI summary
A substrate for a magnetic disk includes a substrate main body and a film. The substrate main body has two opposing main surfaces and an outer circumferential edge surface, and the outer circumferential edge surface includes a side wall surface, which is orthogonal to the main surfaces, and chamfered surfaces, which are disposed between the main surfaces and the side wall surface. The substrate main body is a glass substrate main body or an aluminum alloy substrate main body, and has a disk shape. The film is an alloy film containing Ni and P, and is provided on a surface of the substrate main body such that the film is formed continuously over the main surfaces, the chamfered surfaces, and the side wall surface of the substrate main body.