Magnetic Recording Medium Friction Control via Nonmagnetic Particle Embedding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic recording media face challenges in reducing the coefficient of friction during signal reproduction, which leads to noise increase and output fluctuations, while also striving to enhance electromagnetic characteristics, as the incorporation of nonmagnetic particles to reduce friction often compromises signal quality.
Innovation Solution
A magnetic recording medium with a magnetic layer containing ferromagnetic powder and nonmagnetic particles having a major axis to minor axis length ratio of less than or equal to 1.5, where the nonmagnetic particles are embedded such that their depth to thickness ratio is less than or equal to 0.9, and the number of protrusions greater than or equal to 5 nm in height is optimized to reduce friction and improve electromagnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nonmagnetic particles are incorporated into the magnetic layer to reduce the coefficient of friction, then the coefficient of friction is reduced, but the electromagnetic characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aspect ratio (major axis length/minor axis length) of nonmagnetic particles to be ≤1.5 and the embedding depth ratio (b/t) to be ≤0.9. These parameter optimizations allow the nonmagnetic particles to reduce friction effectively while minimizing their negative impact on electromagnetic characteristics, thus resolving the contradiction between friction reduction and signal quality maintenance.
Solution Approach 2:
The patent uses composite materials by combining ferromagnetic powder with specifically shaped nonmagnetic particles (aspect ratio ≤1.5) in the magnetic layer. This composite structure allows the nonmagnetic particles to provide friction reduction benefits while their controlled geometry ensures they do not excessively disrupt the magnetic properties, thereby balancing both requirements.
2Object-affected harmful factors
If the surface of the magnetic recording medium becomes coarse to reduce contact area, then the coefficient of friction is reduced, but the spacing between the magnetic head and surface increases causing output drop
Solution Approach 1:
The patent optimizes the surface topology parameters by controlling the embedding depth ratio (b/t) of nonmagnetic particles to be ≤0.9 and their aspect ratio to be ≤1.5. This creates a surface with moderate roughness that reduces contact area and friction while maintaining sufficient proximity between the magnetic head and recording surface, thus preventing excessive spacing loss.
Data Source
AI summary
The magnetic recording medium has a magnetic layer containing multiple nonmagnetic particles having a ratio, major axis length/minor axis length, of less than or equal to 1.5, the multiple nonmagnetic particles are present in the magnetic layer in a state where, when the depth to which each of the multiple nonmagnetic particles is embedded in the magnetic layer in observation of a sectional image picked up by SEM is denoted as b and the thickness of the magnetic layer as t, the average value of the ratio of b/t is less than or equal to 0.9, and the number of protrusions 5 nm or greater in height is 800 or greater and the number of protrusions 20 nm or greater in height is 20 or less as measured by AFM per an area 40 μm×40 μm on the magnetic layer side surface of the magnetic recording medium.