Magnetic Recording Medium With Dual-Protrusion Surface for PES Stability
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Solution Overview
Problem
Reducing the height of surface unevenness in magnetic recording media to improve electromagnetic conversion characteristics leads to an increase in the standard deviation of PES values due to repeated use.
Innovation Solution
A tape-shaped magnetic recording medium with a magnetic layer containing magnetic particles, conductive first particles, and second particles with a specific hardness, featuring a concavo-convex shape with controlled height and gradient ratios, and optionally including carbon particles and abrasives, to maintain good electromagnetic conversion characteristics while suppressing the increase in standard deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the height of surface unevenness is reduced to improve electromagnetic conversion characteristics, then electromagnetic conversion characteristics are improved, but the standard deviation of PES values increases due to repeated use
Solution Approach 1:
The invention applies local quality by creating a dual-peak concavo-convex structure with distinct first and second protrusions, each having different heights and material compositions. The first protrusion (height H1) and second protrusion (height H2) are locally differentiated in their physical properties, allowing the magnetic layer to simultaneously achieve smooth overall surface (low standard deviation) while maintaining controlled local height variations (average height difference ≤2.3 nm) for good electromagnetic conversion characteristics.
Solution Approach 2:
The invention employs composite materials by incorporating different particle types in the magnetic layer: magnetic particles for recording functionality, conductive first particles (e.g., carbon particles) for electrical properties, and hard second particles (e.g., alumina with Mohs hardness ≥7.0) for mechanical stability. This composite structure enables the dual-peak concavo-convex shape to maintain both electromagnetic performance and resistance to wear-induced PES variation over repeated use.
2Manufacturing precision
If the average height difference between protrusions is controlled to ≤2.3 nm, then electromagnetic conversion characteristics are maintained, but the structural complexity increases
Solution Approach 1:
The invention applies parameter changes by precisely controlling the height parameter H1 of the first protrusion to satisfy H1/H2 ≤ 2.3, where H2 is the height of the second protrusion. By adjusting this height ratio parameter and the absolute height values (with average height difference ≤2.3 nm), the invention achieves optimal electromagnetic conversion characteristics while managing the complexity of the dual-peak concavo-convex structure through quantitative parameter specification.
3Strength
If hard particles with Mohs hardness of 7.0 or more are added to the magnetic layer, then wear resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention applies local quality by spatially separating different particle functions within the magnetic layer: conductive first particles (e.g., carbon particles) are positioned in the first protrusion regions to provide electrical conductivity and electromagnetic performance, while hard second particles (e.g., alumina with Mohs hardness ≥7.0) are positioned in the second protrusion regions to provide wear resistance. This local differentiation of particle types allows the magnetic layer to simultaneously achieve both electromagnetic conversion characteristics and wear resistance without requiring all particles to possess all properties.
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 maintains good electromagnetic conversion characteristics while effectively reducing the standard deviation of PES values, ensuring stable performance over multiple uses.
Implementation Method 1
In order to obtain good recording/reproducing characteristics (electromagnetic conversion characteristics)
Data Source
AI summary
A magnetic recording medium sequentially includes a base, an underlayer, and a magnetic layer. The magnetic layer includes magnetic particles, conductive first particles, and second particles having a Mohs hardness of 7.0 or more. The magnetic layer has a concavoconvex shape on a magnetic surface, and the concavoconvex shape includes a first protrusion including the first particles and a second protrusion including the second particles. A ratio H1/H2 of an average height H1 of the first protrusion and an average height H2 of the second protrusion satisfies H1/H2≤2.3, a height range ΔH obtained from statistical information on a height of the concavoconvex shape satisfies 3.00 nm≤ΔH≤6.00 nm, and a gradient range ΔA obtained from statistical information on a gradient of the concavoconvex shape satisfies 4.00 degrees≤ΔA≤9.00 degrees.