Cobalt Ferrite Magnetic Powder Coercive Force Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The cobalt ferrite magnetic powder produced by existing methods exhibits large variations in coercive force, which affects the consistency and performance of magnetic recording media.
Innovation Solution
A cobalt ferrite magnetic powder with uniaxial crystal magnetic anisotropy, where some cobalt (Co) is substituted with Zn, Ge, or transition metal elements like Cu, and produced through a glass crystallization method involving heat treatment under low oxygen partial pressure, ensuring a specific peak position in X-ray diffractometry and controlled particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical milling or additive introduction methods are used to produce cobalt ferrite magnetic powder, then the magnetic powder can be obtained, but the coercive force Hc shows large variation
Solution Approach 1:
The invention changes the oxygen partial pressure parameter during heat treatment to 1.0 kPa or less, which fundamentally alters the oxidation environment. This parameter change leads to controlled substitution of Co atoms by Zn, Ge, or other transition metal elements, resulting in consistent coercive force values and reduced variation in the magnetic powder properties.
Solution Approach 2:
The invention introduces local chemical substitution at specific lattice sites within the cobalt ferrite structure. By substituting some Co atoms with Zn, Ge, or other transition metal elements at the octahedral sites, the local magnetic environment is modified, creating uniform magnetic properties throughout the powder that reduce coercive force variation.
2Manufacturing precision
If heat treatment is performed under atmospheric oxygen conditions, then the magnetic powder can be crystallized, but the coercive force variation increases
Solution Approach 1:
The invention employs a low oxygen partial pressure environment (1.0 kPa or less) during heat treatment, creating an oxygen-limited atmosphere that prevents excessive oxidation. This controlled inert-like environment enables proper crystallization of cobalt ferrite while simultaneously achieving the desired Co substitution that stabilizes coercive force, thus resolving the contradiction between crystallization and coercive force stability.
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 solution stabilizes the coercive force and reduces variations, enhancing the magnetic properties and recording performance of the magnetic medium by maintaining a consistent coercive force and improving electromagnetic conversion characteristics.
Implementation Method 1
performing heat treatment on the amorphous body to precipitate the cobalt ferrite magnetic powder
Implementation Method 2
a peak top 2θ of a (3, 1, 1) plane determined by powder X-ray diffractometry using a CoKα ray is 41.3° or more and 41.5° or less
Data Source
AI summary
A cobalt ferrite magnetic powder includes magnetic particles that have a uniaxial crystal magnetic anisotropy and contain cobalt ferrite. A peak top 2θ of a (3, 1, 1) plane determined by powder X-ray diffractometry using a CoKα ray is 41.3° or more and 41.5° or less. Some Cos contained in the magnetic particles are substituted with at least one selected from the group consisting of Zn, Ge, and a transition metal element other than Fe.