Magnetic Tape Surface Roughness and Back Coating Stability
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Solution Overview
Problem
Magnetic tapes with high surface smoothness of the magnetic layer, specifically with a center line average surface roughness Ra of 1.8 nm or less, experience edge damage due to unstable contact between the magnetic layer and the back coating layer during winding, leading to increased errors and reduced running stability.
Innovation Solution
A magnetic tape design incorporating a non-magnetic support with a magnetic layer containing ferromagnetic hexagonal ferrite powder, non-magnetic powder, and a binding agent on one surface, and a back coating layer with non-magnetic powder and a binding agent on the other surface, where the magnetic layer surface roughness Ra is maintained at 1.8 nm or less, and the XRD intensity ratio, vertical squareness ratio, and logarithmic decrement of the back coating layer are optimized to enhance contact stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic layer surface roughness is reduced to 1.8 nm or less to improve electromagnetic conversion characteristics, then the electromagnetic conversion characteristics are improved, but edge damage occurs due to unstable contact between layers during winding
Solution Approach 1:
The invention changes the surface roughness parameter of the magnetic layer to a specific range (Ra 1.2-1.8 nm) and controls the XRD intensity ratio and vertical squareness ratio as additional parameters. This multi-parameter optimization resolves the contradiction by finding the precise parameter window that achieves both smooth surface for electromagnetic performance and stable layer contact for edge damage prevention
Solution Approach 2:
The invention uses a composite structure with magnetic layer containing ferromagnetic hexagonal ferrite powder and non-magnetic powder, combined with a back coating layer. This composite material approach allows independent optimization of magnetic properties and mechanical stability, resolving the contradiction between surface smoothness and layer adhesion
2Measurement precision
If the magnetic layer surface roughness is reduced to increase surface smoothness, then electromagnetic conversion characteristics are improved, but the contact stability between magnetic layer and back coating layer deteriorates
Solution Approach 1:
The invention introduces multiple controlled parameters including surface roughness Ra (1.2-1.8 nm), XRD intensity ratio (0.5-4.0), and vertical squareness ratio (0.65-1.00). This multi-parameter control system allows the magnetic layer to maintain both smooth surface and stable contact by optimizing the interplay between these parameters
Solution Approach 2:
The back coating layer acts as an intermediary between the magnetic layer and the external environment, providing mechanical support and stabilizing the magnetic layer. By controlling the logarithmic decrement of the back coating layer surface (≤0.060), the intermediary layer ensures stable contact while allowing the magnetic layer surface to remain smooth
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 optimized magnetic tape prevents edge damage by stabilizing the contact between the magnetic layer and the back coating layer, thereby reducing errors and improving running stability, while maintaining high electromagnetic conversion characteristics.
Implementation Method 1
a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent on one surface side of the non-magnetic support; the ferromagnetic powder is ferromagnetic hexagonal ferrite powder
Implementation Method 2
a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent on one surface side of the non-magnetic support; a back coating layer including non-magnetic powder and a binding agent on the other surface side of the non-magnetic support
Data Source
AI summary
The magnetic tape includes a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent and a back coating layer including non-magnetic powder and a binding agent, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, an Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the back coating layer is equal to or smaller than 0.060.