Ferrite Sintered Magnet Composition for Reduced Firing Temperature Dependence
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Solution Overview
Problem
Conventional ferrite sintered magnets exhibit significant variation in magnetic properties due to firing temperature dependence, which is not adequately addressed in existing technologies.
Innovation Solution
A ferrite sintered magnet composition comprising rare earth elements, Ca, Sr, Ba, Fe, Co, B, Mn, and Cr, with specific atomic ratios and content ranges, is developed to minimize firing temperature dependence and enhance coercive force and residual magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If various elements are added to improve Br and HcJ, then magnetic properties are improved, but firing temperature dependence of magnetic properties increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the atomic ratios of multiple elements in the ferrite composition. Specifically, it sets x between 0.2-0.8, y between 0.1-0.65, and m between 3-14 in the formula R1-xMxFem-yCoy, along with specific mass percentages for B (0.1-0.4%), Mn (0.15-1.02%), and Cr (0.02-2.01%). This multi-parameter optimization resolves the contradiction by achieving both improved magnetic properties and reduced firing temperature dependence simultaneously.
Solution Approach 2:
The patent employs composite materials by combining multiple rare earth elements (R) with alkaline earth elements (M), transition metals (Co, Mn, Cr), and oxide additives (B, Mn, Cr). This composite approach creates a synergistic effect where the combination of elements produces both high magnetic properties and thermal stability, resolving the technical contradiction between improving magnetic performance and maintaining compositional stability during firing.
2Ease of manufacture
If conventional ferrite composition is used, then manufacturing is simple, but variation in magnetic properties is significant
Solution Approach 1:
The patent maintains ease of manufacture by using conventional sintering processes while improving manufacturing precision through precise compositional control. The specific atomic ratios (x, y, m parameters) and mass percentages of additives are optimized to reduce magnetic property variation, allowing standard manufacturing equipment and processes to produce consistent, high-quality magnets without complex additional steps.
Solution Approach 2:
The patent substitutes mechanical/compositional optimization for complex process control. Instead of requiring sophisticated manufacturing processes to control magnetic property variation, the invention achieves precision through careful selection and ratio control of chemical elements in the composition, replacing the need for complex mechanical or process control systems with a chemically optimized formulation.
Data Source
AI summary
This ferrite sintered magnet comprises ferrite phases having a magnetoplumbite type crystal structure. This magnet comprises an element R, an element M, Fe, Co, B, Mn and Cr, the element R is at least one element selected from rare earth elements including Y, the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element, and when an atomic composition of metallic elements is represented by R1-xMxFem-yCoy, x, y and m satisfy formulae:0.2≤x≤0.8 (1)0.1≤y≤0.65 (2)3≤m<14 (3).Additionally, a content of B is 0.1 to 0.4% by mass in terms of B2O3, a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and a content of Cr is 0.02 to 2.01% by mass in terms of Cr2O3.