Magnetic Recording Medium Indentation Tuning for Humid-Environment Durability

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Solution Overview

Problem

Magnetic recording media face challenges in improving running durability in high humidity environments.

Innovation Solution

A magnetic recording medium comprising a support body, a base layer containing carbon particle powder and metal-containing particle powder, with a maximum indentation depth of 85≤h≤140 and a ratio of permanent strain to elastic recovery of 0.95≤d≤1.25, enhancing durability in high humidity conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coating-type magnetic recording medium is used, then manufacturing simplicity is maintained, but running durability in high humidity environments deteriorates

Engineering Contradiction:

Improverunning durabilityVSAvoidhigh humidity environment effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the indentation hardness (DH) of the magnetic layer surface within 25-80 Kg/mm2 and the maximum indentation depth h within 85-140 nm. These parameter optimizations improve the magnetic layer's resistance to humidity-induced degradation while maintaining coating-type manufacturing simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by formulating the magnetic layer with specific combinations of binders and magnetic particles that achieve the target indentation hardness and depth parameters. The composite structure provides enhanced durability in high humidity environments while preserving the coating-type manufacturing approach

Inventive Principle:

Principle #40Composite materials

2Reliability

If indentation hardness is increased to improve running durability, then reliability improves, but manufacturing precision requirements worsen

Engineering Contradiction:

Improverunning durabilityVSAvoidindentation hardness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent defines a specific parameter range for indentation hardness (DH = 25-80 Kg/mm2) that balances durability improvement with manufacturing feasibility. This parameter optimization allows conventional coating processes to achieve the required performance without excessive precision demands

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by targeting a moderate indentation hardness range rather than maximum possible hardness. This approach achieves sufficient running durability while avoiding the manufacturing precision challenges associated with extreme hardness values

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12394436B2Magnetic recording medium

Publication Date: 2025.08.19 SONY GROUP CORP

AI summary

Provided is a magnetic recording medium including: a support body; a base layer containing carbon particle powder and metal-containing particle powder; and a recording layer. In a recording surface, a maximum indentation depth h is 85≤h≤140, and a ratio d of a permanent strain to an elastic recovery (permanent strain/elastic recovery) is 0.95≤d≤1.25.