Magnetic Recording Medium Hexagonal Ferrite Sliding Reliability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Magnetic recording media experience deterioration in electromagnetic conversion characteristics due to spacing loss caused by head attachment and foreign substances, leading to reduced reliability during repeated sliding.

Innovation Solution

A magnetic recording medium with a non-magnetic support and a magnetic layer containing ferromagnetic hexagonal ferrite powder, abrasive, and specific XRD intensity and squareness ratios, along with a controlled 1-bromonaphthalene contact angle, to inhibit head and magnetic layer scraping and improve sliding affinity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an abrasive is added to the magnetic layer to remove head attachment, then the electromagnetic conversion characteristics are improved, but the surface of the magnetic layer becomes damaged and foreign substances are generated

Engineering Contradiction:
Improveelectromagnetic conversion characteristicsVSAvoidforeign substances from magnetic layer
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A transfer layer is introduced between the magnetic layer and the head to serve as an intermediary. This transfer layer contains abrasive particles that can be transferred to the head during sliding, allowing the head attachment to be removed without damaging the magnetic layer or generating foreign substances from it.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The abrasive function is extracted from the magnetic layer and relocated to a separate transfer layer. This allows the magnetic layer to maintain its integrity while the transfer layer performs the abrasive cleaning function by transferring abrasive particles to the head.

Inventive Principle:
Principle #2Taking out (Extraction)

2Duration of action of moving object

If the head repeatedly slides on the magnetic layer for continuous reproduction, then the recording medium can be used continuously, but the electromagnetic conversion characteristics deteriorate due to spacing loss

Engineering Contradiction:
Improvecontinuous reproduction capabilityVSAvoidelectromagnetic conversion characteristics
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The transfer layer is pre-equipped with abrasive particles before the head slides on the magnetic layer. This preliminary preparation allows the abrasive particles to be transferred to the head during normal operation, preventing head attachment accumulation and maintaining electromagnetic conversion characteristics throughout continuous use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transfer layer automatically transfers abrasive particles to the head during the sliding process, enabling self-cleaning of the head without external intervention. This continuous self-service mechanism maintains reliable electromagnetic conversion characteristics during repeated sliding operations.

Inventive Principle:
Principle #25Self-service

3Strength

If the magnetic layer surface is made hard to resist head scraping, then the surface durability is improved, but the sliding affinity deteriorates and head attachment increases

Engineering Contradiction:
Improvesurface hardnessVSAvoidhead attachment
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

Different layers are assigned different properties: the magnetic layer maintains its original composition and surface characteristics for good sliding affinity, while the transfer layer contains abrasive particles for head cleaning. This local differentiation allows each layer to perform its specific function without compromise.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The transfer layer is constructed as a composite material containing abrasive particles dispersed in a binder resin. This composite structure provides both the hardness needed for abrasive action and the appropriate surface properties for sliding, while being distinct from the magnetic layer.

Inventive Principle:
Principle #40Composite materials

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 the deterioration of electromagnetic conversion characteristics during repeated sliding, enhancing the reliability and performance of the magnetic recording medium by maintaining excellent conversion characteristics and reducing surface damage.

Implementation Method 1

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

an abrasive has been added to the magnetic layer such that the surface of the magnetic layer performs a function of removing the head attachment

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

an intensity ratio (Int (110)/Int (114)) of a peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS10714139B2Magnetic recording medium having characterized magnetic layer
Publication Date: 2020.07.14 FUJIFILM CORP

AI summary

The magnetic recording medium includes a non-magnetic support and a magnetic layer containing ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, an intensity ratio of a peak intensity of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, and a contact angle with 1-bromonaphthalene measured within a surface of the magnetic layer is in a range of 50.0° to 55.0°.