Hexagonal Ferrite Particle Synthesis via Surfactant Coating
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Solution Overview
Problem
Current methods for manufacturing hexagonal ferrite magnetic particles, such as the coprecipitation and reverse micelle methods, face challenges in obtaining fine particles due to sintering and aggregation during calcination, which hinders the achievement of higher recording densities in magnetic recording media.
Innovation Solution
A method involving the use of a surfactant-coated iron oxide particles, adhered with a glass component and an alkaline earth metal in a water-based solution, followed by calcination, to inhibit sintering and promote ferrite conversion, resulting in fine hexagonal ferrite magnetic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coprecipitation method or reverse micelle method is used to manufacture hexagonal ferrite particles, then ferrite conversion is achieved through calcination, but particles sinter and aggregate making it difficult to obtain fine particles
Solution Approach 1:
The patent applies a surfactant to the iron oxide particles before calcination to form a protective coating. This preliminary action prevents particle aggregation during the subsequent calcination process, enabling the production of fine hexagonal ferrite particles with controlled size distribution while maintaining adequate ferrite conversion.
Solution Approach 2:
The surfactant acts as an intermediary substance between the iron oxide particles and the calcination process. It forms a protective layer that mediates the interaction during high-temperature treatment, preventing direct particle-to-particle contact and sintering while allowing the necessary ferrite conversion to proceed.
2Reliability
If calcination is conducted without surfactant coating, then ferrite conversion may be adequate, but particles aggregate and sinter during the process
Solution Approach 1:
The surfactant is applied to iron oxide particles before calcination to form a protective coating. This preliminary action maintains particle separation during the high-temperature treatment, preventing aggregation while allowing the calcination process to proceed sufficiently for ferrite conversion.
Solution Approach 2:
The patent creates a composite structure where surfactant molecules form a protective layer around iron oxide particles. This composite approach combines the benefits of surfactant-based aggregation prevention with the thermal processing benefits of calcination for ferrite conversion, achieving both particle size control and phase transformation.
3Stability of the object's composition
If alkaline earth metal compound is used to prevent sintering during calcination, then some sintering prevention is achieved, but the effect is not adequate for high-density recording
Solution Approach 1:
The surfactant serves as an intermediary protective layer that more effectively prevents sintering during calcination compared to alkaline earth metal compounds. It forms a stable coating that maintains particle separation at high temperatures, enabling the production of finer particles suitable for high-density magnetic recording applications.
Solution Approach 2:
The patent changes the protective mechanism from chemical (alkaline earth metal compounds) to physical-chemical (surfactant coating). This parameter change in the nature of the protective layer provides superior sintering prevention, allowing particles to remain fine and discrete after calcination treatment.
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 approach effectively prevents sintering and ensures adequate ferrite conversion, enabling the production of fine hexagonal ferrite magnetic particles suitable for high-density magnetic recording media with maintained magnetic characteristics.
Implementation Method 1
subjecting iron oxide particles to which a surfactant adheres
Implementation Method 2
adhering with an adhering matter comprising a glass component and an alkaline earth metal
Implementation Method 3
calcining the iron oxide particles to which the adhering matter adheres to obtain a calcined product in which a main component that is detected by X-ray diffraction analysis is hexagonal ferrite
Data Source
AI summary
The method of manufacturing hexagonal ferrite magnetic particles comprises applying, in a water-based solution, an adhering matter comprising a glass component and an alkaline earth metal to iron oxide particles to which a surfactant adheres, and calcining the iron oxide particles to which the adhering matter adheres to obtain a calcined product in which a main component that is detected by X-ray diffraction analysis is hexagonal ferrite.