Magnetic Tape Surface Hardness for Head Chipping Prevention
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Solution Overview
Problem
Magnetic tapes used for archive purposes face challenges in maintaining excellent electromagnetic conversion characteristics and preventing head element chipping during the green tape test (GTT), where frequent changes of magnetic tapes with a new head lead to severe head element chipping due to increased wear and spacing loss.
Innovation Solution
A magnetic tape with a non-magnetic support and a magnetic layer containing ferromagnetic powder, oxide abrasive, and a binding agent, where the switching field distribution difference (ΔSFD) is ≤0.50, logarithmic decrement is ≤0.050, and the average particle diameter of the oxide abrasive is between 0.04 μm and 0.08 μm, ensuring optimal alignment and surface properties to prevent chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is provided on the head to prevent head element chipping, then head element chipping is reduced, but the distance between the magnetic layer surface and reproducing element increases causing spacing loss
Solution Approach 1:
The patent changes the physical and chemical parameters of the magnetic layer surface by controlling the oxide abrasive particle size (0.03-0.06 μm) and its content (0.5-5 parts by mass),以及 the binding agent properties, to achieve optimal surface smoothness and hardness that prevent head element chipping without requiring a protective layer, thus avoiding spacing loss
Solution Approach 2:
The patent uses a composite magnetic layer comprising ferromagnetic powder, oxide abrasive, and binding agent, where the oxide abrasive (such as alumina or silica) provides surface hardness and wear resistance, preventing head element chipping while maintaining surface smoothness to avoid spacing loss
2Productivity
If multiple new magnetic tapes are slid with respect to one head in GTT, then archive performance is tested, but head element chipping occurs significantly easier compared to repeated sliding of one tape
Solution Approach 1:
The patent optimizes the magnetic layer surface parameters including oxide abrasive particle size (0.03-0.06 μm), abrasive content (0.5-5 parts by mass), and binding agent properties to achieve a surface that minimizes wear and prevents head element chipping during GTT where multiple tapes are slid against one head
Solution Approach 2:
The patent applies oxide abrasive specifically at the magnetic layer surface to create a localized hard, wear-resistant layer that protects against head element chipping during the severe sliding conditions of GTT, while the bulk magnetic layer maintains its magnetic recording properties
3Reliability
If the magnetic layer surface is worn through repeated sliding, then head element chipping becomes less likely, but electromagnetic conversion characteristics deteriorate
Solution Approach 1:
The patent performs preliminary action by incorporating oxide abrasive into the magnetic layer before recording, creating a pre-hardened surface that prevents head element chipping from the outset, eliminating the need for wear that would otherwise occur during repeated sliding
Solution Approach 2:
The patent creates a composite magnetic layer structure where oxide abrasive particles are distributed within the magnetic layer, providing surface hardness and wear resistance while the ferromagnetic powder maintains electromagnetic conversion characteristics, allowing both head element chipping prevention and excellent signal reproduction
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 magnetic tape exhibits excellent electromagnetic conversion characteristics and effectively prevents head element chipping during the GTT, maintaining high signal-to-noise ratio (SNR) and reducing wear-related issues.
Implementation Method 1
One performance required from the magnetic tape is to exhibit excellent electromagnetic conversion characteristics in a case of reproducing information recorded on the magnetic tape
Implementation Method 2
a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support
Implementation Method 3
a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050
Implementation Method 4
an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam (FIB) is 0.04 μm to 0.08 μm
Data Source
AI summary
Provided are a magnetic tape, in which a magnetic layer includes a ferromagnetic powder, a binding agent, and an oxide abrasive, ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1, ΔSFD=SFD25° C.−SFD−190° C., is equal to or smaller than 0.50, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic tape.