Hexagonal Ferrite Particle Manufacturing via Glass Coating
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Solution Overview
Problem
Existing methods for manufacturing hexagonal ferrite magnetic particles, such as the coprecipitation and reverse micelle methods, face challenges in preventing sintering during calcination, which hinders the production of minute particles necessary for high-density magnetic recording.
Innovation Solution
Adhering a glass component to the iron salt before adding the alkaline earth metal salt and conducting calcination, allowing for the formation of hexagonal ferrite as the principal component, while controlling the quantity of the glass component to prevent hematite formation and ensure ferrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coprecipitation or reverse micelle method is used to manufacture hexagonal ferrite particles, then ferrite particles can be produced, but the particles sinter and aggregate during calcination, making it difficult to achieve minute particles
Solution Approach 1:
An alkaline earth metal compound is introduced as an intermediary substance that coats the surface of ferrite precursor particles before calcination. This coating layer acts as a physical barrier that prevents direct contact and sintering between particles during the high-temperature calcination process, thereby maintaining particle dispersion and enabling production of minute ferrite particles without aggregation
Solution Approach 2:
The alkaline earth metal compound is applied to the particle surface in advance before the calcination step. This preliminary coating ensures that the protective layer is already in place when heating begins, preventing sintering from the outset during the temperature rise and maintaining particle size control throughout the entire calcination process
2Manufacturing precision
If alkaline earth metal compound is used to inhibit sintering during calcination, then particle aggregation is reduced, but the anti-sintering effect is not necessarily adequate for achieving higher density recording
Solution Approach 1:
The invention uses a composite coating system consisting of alkaline earth metal compounds combined with specific organic additives or surfactants. This composite approach enhances the anti-sintering effect by providing both physical barrier properties from the inorganic compound and surface stabilization from the organic components, achieving more reliable particle size control for high-density recording applications
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 method effectively inhibits sintering during calcination, enabling the production of microparticulate hexagonal ferrite magnetic particles with sizes ranging from 10 to 20 nm, suitable for high-density magnetic recording applications.
Implementation Method 1
adhering a glass component and then the alkaline earth metal salt to the iron salt
Implementation Method 2
adhering a glass component and then the alkaline earth metal salt to the iron salt
Implementation Method 3
conducting calcination of a coprecipitate obtained by coprecipitating an iron salt and an alkaline earth metal salt
Data Source
AI summary
The method of manufacturing hexagonal ferrite magnetic particles includes providing hexagonal ferrite magnetic particles by conducting calcination of particles comprising an iron salt and an alkaline earth metal salt to cause fertilization; and further includes preparing the particles comprising an iron salt and an alkaline earth metal salt by adhering a glass component, followed by the alkaline earth metal salt, to the iron salt; and conducting calcination of the particles prepared to form a calcined product in which hexagonal ferrite is detected as a principal component in X-ray diffraction analysis.