Back Coating Layer Spacing Control for Magnetic Media
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Solution Overview
Problem
Magnetic recording media with a back coating layer experience a decrease in reproduction output when stored at high temperatures and then used in low-temperature, high-humidity environments, due to the transfer of lubricant components from the magnetic layer to the back coating layer, affecting running stability.
Innovation Solution
A magnetic recording medium with a back coating layer where the difference in spacing measured under different pressures is maintained at 3 nm or less, preventing deformation and subsequent transfer of components, thereby maintaining reproduction output across varying environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a back coating layer is provided on the magnetic recording medium, then running stability is improved, but reproduction output decreases after storage at high temperature and repeated use in low-temperature, high-humidity environments
Solution Approach 1:
The invention changes the physical parameter of the back coating layer by controlling the spacing difference (S0.5−S13.5) to be 3 nm or less. This parameter control prevents the transfer of lubricant components from the magnetic layer to the back coating layer under temperature-humidity conditions, thereby maintaining reproduction output while preserving running stability.
2Reliability
If the back coating layer spacing difference (S0.5−S13.5) is large, then component transfer is suppressed, but running stability deteriorates
Solution Approach 1:
The invention identifies and controls the critical parameter of spacing difference (S0.5−S13.5) in the back coating layer. By setting this parameter to 3 nm or less, the invention achieves optimal balance: the back coating layer remains dense enough to prevent lubricant transfer (maintaining reproduction output) while preserving sufficient spacing for running stability.
Data Source
AI summary
The magnetic recording medium includes a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 3 nm or less.