Magnetic Recording Medium Surface Roughness Control
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Solution Overview
Problem
Magnetic recording media with high surface smoothness experience deterioration in electromagnetic conversion characteristics due to temperature changes from low to high temperatures under high humidity conditions.
Innovation Solution
A magnetic recording medium with a non-magnetic support and a magnetic layer comprising ferromagnetic powder and a binding agent, where the center line average surface roughness is between 1.0 nm to 1.6 nm, and a spacing difference measured before and after methyl ethyl ketone cleaning is between 0 nm and 15.0 nm, to prevent moisture attachment and friction increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface smoothness of the magnetic layer is increased to improve electromagnetic conversion characteristics, then the electromagnetic conversion characteristics are improved, but the magnetic recording medium becomes sensitive to temperature and humidity changes causing deterioration in electromagnetic conversion characteristics
Solution Approach 1:
The patent optimizes the surface roughness parameter Ra to a specific range (1.0 nm to 1.6 nm) to achieve the best balance between electromagnetic conversion characteristics and environmental stability. This parameter optimization prevents both excessive smoothness that causes moisture attachment and insufficient smoothness that degrades electromagnetic characteristics.
Solution Approach 2:
The patent applies different surface quality requirements to different aspects: the magnetic layer surface is controlled to have specific roughness characteristics (Ra 1.0-1.6 nm) for optimal electromagnetic performance, while the spacing control (Safter-Sbefore ≤ 15.0 nm) ensures local stability against environmental changes. This local quality differentiation resolves the contradiction between smoothness and stability.
2Manufacturing precision
If the surface smoothness is increased beyond a certain level, then electromagnetic conversion characteristics improve, but moisture attachment increases causing friction increase and performance deterioration
Solution Approach 1:
The patent identifies and optimizes the critical parameter Ra (surface roughness) to a specific range (1.0 nm to 1.6 nm). This parameter optimization creates the ideal surface condition that prevents moisture attachment while maintaining excellent electromagnetic conversion characteristics, resolving the contradiction between smoothness and moisture resistance.
Solution Approach 2:
The patent converts the potential harm of high surface smoothness (which could cause moisture attachment) into a benefit by precisely controlling the roughness to 1.0-1.6 nm. This controlled micro-roughness actually prevents moisture attachment while maintaining electromagnetic performance, turning a potential problem into a solution.
3Reliability
If the spacing difference before and after methyl ethyl ketone cleaning is reduced to prevent moisture attachment, then electromagnetic conversion characteristics stability is improved, but surface smoothness may be compromised
Solution Approach 1:
The patent optimizes two parameters simultaneously: Ra (surface roughness) to 1.0-1.6 nm and spacing difference (Safter-Sbefore) to ≤ 15.0 nm. This dual parameter optimization achieves both goals: maintaining surface smoothness for electromagnetic performance and controlling spacing to prevent moisture attachment, thereby resolving the contradiction between reliability and manufacturing precision.
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 solution effectively prevents deterioration in electromagnetic conversion characteristics by maintaining surface smoothness and reducing moisture attachment, ensuring stable performance under varying temperature and humidity conditions.
Implementation Method 1
a center line average surface roughness Ra measured regarding a surface of the magnetic layer is 1.0 nm to 1.6 nm
Implementation Method 2
a spacing difference (Safter−Sbefore) before and after methyl ethyl ketone cleaning measured by optical interferometry
Data Source
AI summary
The magnetic recording medium including: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer is 1.0 nm to 1.6 nm, and a difference (Safter−Sbefore) between a spacing Safter measured by optical interferometry regarding the surface of the magnetic layer after methyl ethyl ketone cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the magnetic layer before methyl ethyl ketone cleaning is greater than 0 nm and equal to or smaller than 15.0 nm.