Magnetic Recording Medium Lubricant Layer Fabrication

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Solution Overview

Problem

Existing magnetic recording medium fabrication methods face challenges in simultaneously achieving a low coefficient of friction for the lubricant layer and high surface coverage of the protection layer, which are crucial for reducing friction and enhancing corrosion resistance when the magnetic recording medium contacts a magnetic head.

Innovation Solution

A method involving sequential formation of a magnetic recording layer, protection layer, and lubricant layer, where a first lubricant is deposited using vapor-phase lubrication deposition, followed by a second lubricant dissolved in an organic solvent, allowing for substitution of the first lubricant to enhance the bonded ratio and include a suitable free layer, thereby improving the lubricant layer's coverage and corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If vapor-phase lubrication is used to form the lubricant layer, then the coefficient of friction is reduced, but the surface coverage of the protection layer is insufficient

Engineering Contradiction:

Improvecoefficient of frictionVSAvoidsurface coverage of protection layer

Core Design Contradiction:

ForceVSArea of stationary object

Solution Approach 1:

The lubricant layer is formed as a composite structure with a bond layer and a free layer. The bond layer provides strong adhesion to the protection layer, while the free layer provides low friction properties. This composite structure resolves the contradiction by combining materials with different functions to achieve both high surface coverage and low coefficient of friction.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the lubricant layer are given different properties: the bond layer (near the protection layer) has high adhesion strength, while the free layer (surface region) has low friction coefficient. This local differentiation allows simultaneous optimization of both surface coverage and friction reduction.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the lubricant layer is made thick to improve coverage, then the surface coverage increases, but the friction reduction effect decreases

Engineering Contradiction:

Improvesurface coverage of protection layerVSAvoidcoefficient of friction

Core Design Contradiction:

Area of stationary objectVSForce

Solution Approach 1:

The lubricant layer is structured with different thicknesses and properties in different regions. The bond layer has sufficient thickness to ensure high surface coverage and strong adhesion, while the free layer maintains optimal thickness for friction reduction. This local quality differentiation resolves the contradiction between coverage and friction reduction.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a single lubricant material is used, then the fabrication process is simple, but both bonded ratio and free layer requirements cannot be met

Engineering Contradiction:

Improvefabrication process simplicityVSAvoidbonded ratio and free layer quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The lubricant layer is formed by depositing multiple lubricant materials with different properties. The first lubricant material forms the bond layer with high adhesion, while the second lubricant material forms the free layer with low friction. This composite approach meets the reliability requirements while maintaining processability through sequential deposition.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The lubricant layer formation process is segmented into multiple deposition steps, with each step forming a specific functional layer. The first deposition forms the bond layer, and the second deposition forms the free layer. This segmentation allows independent optimization of each layer's properties while maintaining overall process control.

Inventive Principle:

Principle #1Segmentation

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

This approach results in a lubricant layer with a high bonded ratio and suitable free layer, providing improved reliability and corrosion resistance for the magnetic recording medium, while maintaining low friction during contact with the magnetic head.

Implementation Method 1

depositing a first lubricant on the stacked body after forming the protection layer, by vapor-phase lubrication deposition, without exposing the stacked body to atmosphere

Methodology Applied

Scientific EffectVapor-phase lubrication deposition: Physical Vapour Deposition

Implementation Method 2

depositing a second lubricant that is dissolved in an organic solvent onto the stacked body after depositing the first lubricant

Methodology Applied

Scientific EffectSolution deposition: Deposition (physical)

Data Source

PatentUS9159354B2Magnetic recording medium fabrication method

Publication Date: 2015.10.13 RESONAC HARD DISK CORP

AI summary

A method of fabricating a magnetic recording medium by sequentially forming a magnetic recording layer, a protection layer, and a lubricant layer on a stacked body, includes forming the lubricant by depositing a first lubricant on the stacked body after forming the protection layer, by vapor-phase lubrication deposition, without exposing the stacked body to atmosphere, and depositing a second lubricant that is dissolved in an organic solvent onto the stacked body after depositing the first lubricant.