Magnetic Recording Medium Indented Ferrite Particles
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Solution Overview
Problem
The reduction in size of ferromagnetic hexagonal ferrite powder microparticles in magnetic recording media leads to a decrease in durability, compromising the magnetic recording medium's ability to maintain high-density recording capabilities and electromagnetic characteristics.
Innovation Solution
Incorporating a prescribed quantity of ferromagnetic hexagonal ferrite particles with indentations into the magnetic layer, formed during the dispersion process by controlling the temperature to prevent particle splitting, enhances the durability and electromagnetic properties of the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of ferromagnetic hexagonal ferrite powder microparticles is reduced to enhance recording density, then high-density recording capabilities are improved, but durability of the magnetic recording medium deteriorates
Solution Approach 1:
The invention applies local quality by creating indentations at specific locations on particle surfaces. These localized structural modifications (indentations occupying 5-50% of particle surfaces) concentrate bonding sites at specific regions, allowing small particles to achieve strong adhesion to binder resin through enhanced local interaction rather than relying on overall particle size. This resolves the contradiction by enabling high recording density with small particles while maintaining durability through localized surface enhancement.
Solution Approach 2:
The invention applies preliminary action by pre-forming indentations on particle surfaces before the particles are incorporated into the magnetic layer. This advance preparation of surface structures ensures that when small particles are used for high-density recording, they already possess enhanced bonding capability with the binder resin, thereby maintaining durability despite the reduced particle size. The indentations are created during particle synthesis or surface treatment prior to layer formation.
2Measurement precision
If the size of microparticles is reduced to enhance electromagnetic characteristics, then signal/noise ratio is improved, but film strength decreases
Solution Approach 1:
The invention applies local quality by concentrating bonding enhancement at specific locations (indentations) on particle surfaces. These indentations create high-density bonding zones that strengthen the film structure locally, compensating for the reduced overall particle size. The indentations occupy 5-50% of particle surfaces and provide concentrated adhesion points with binder resin, maintaining film strength even when particles are reduced to sizes that improve electromagnetic characteristics.
Solution Approach 2:
The invention applies composite materials by creating particles with combined features: the core maintains small size for improved electromagnetic characteristics, while the surface incorporates indentation structures that enhance mechanical bonding. This composite structure (smooth core + indented surface) allows simultaneous achievement of high signal/noise ratio through small particle size and high film strength through enhanced surface bonding with binder resin.
Data Source
AI summary
An aspect of the present invention relates to a magnetic recording medium, which comprises magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the ferromagnetic hexagonal ferrite powder has an activation volume ranging from 800 nm3 to 1,300 nm3, and 1 percent to 50 percent of particles constituting the ferromagnetic hexagonal ferrite powder are ferromagnetic hexagonal ferrite particles, each of which has an indentation with a depth of equal to or more than 1/10 of an equivalent projected circle diameter of the ferromagnetic hexagonal ferrite particle.