Oxide Matrix Composite Member for Rare-Earth Magnet Protection
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Solution Overview
Problem
Hydraulic composition bonded magnets used to prevent oxidation of rare earth magnets have many pores due to hydration reactions, leading to insufficient protection of magnetic properties from oxygen and water vapor.
Innovation Solution
A composite member with an inorganic matrix made from metal oxides or metal oxide hydroxides, containing no single metals or alloys, and a ferromagnetic material part directly bonded within this matrix, where the inorganic matrix has a larger volume ratio than the ferromagnetic material, reducing contact with oxygen and water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic composition is used to bond magnetic powder, then corrosion resistance and heat resistance are improved, but porosity increases leading to insufficient protection against oxidation
Solution Approach 1:
The patent changes the chemical composition parameters of the bonding material from hydraulic composition to non-hydraulic composition containing specific metal oxides (Al2O3, SiO2, B2O3) in controlled ratios. This parameter change eliminates the hydration reaction that causes porosity while maintaining corrosion resistance and heat resistance properties.
Solution Approach 2:
The patent uses a composite bonding material composed of multiple metal oxides (alumina, silica, boric oxide) in specific proportions. This composite structure provides both mechanical strength and dense protection against oxidation, resolving the contradiction between bonding performance and porosity reduction.
2Strength
If hydraulic powder is hardened through hydration reaction, then bonding strength is improved, but pore formation occurs reducing protection capability
Solution Approach 1:
The patent changes the bonding mechanism from hydration-based hardening to a different chemical system using non-hydraulic metal oxide composition. This eliminates pore formation during setting while maintaining adequate bonding strength through the composite oxide structure and controlled composition ratios.
Solution Approach 2:
The patent creates a dense, pore-free local structure in the bonding material that specifically addresses the oxidation protection requirement. The non-hydraulic composition ensures uniform densification without the pore formation inherent in hydraulic systems, providing localized protection where needed.
3Reliability
If ferromagnetic material is protected from oxygen contact, then magnetic properties are maintained, but bonding material density must be increased
Solution Approach 1:
The patent changes the compositional parameters of the bonding material to achieve high density without porosity. By using non-hydraulic metal oxide composition with specific ratios of Al2O3, SiO2, and B2O3, the material sets without forming pores, thereby achieving the required density for effective oxygen barrier protection.
Solution Approach 2:
The patent creates a dense, pore-free structure that effectively replicates the protective function needed. The non-hydraulic bonding material produces a uniform, dense matrix that copies the ideal protective barrier structure, preventing oxygen penetration without the defects of hydraulic systems.
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 composite member effectively suppresses the deterioration of ferromagnetic substances, maintaining magnetic properties over a long period while enhancing mechanical strength and reducing porosity.
Implementation Method 1
magnets made from active metallic materials, such as rare earth magnets, are easily oxidized by oxygen or the like, and the magnetic properties deteriorate
Implementation Method 2
particles of the inorganic substance are continuously present in the inorganic matrix part
Data Source
AI summary
Provided is a composite member including: an inorganic matrix part made from an inorganic substance that includes at least one of a metal oxide or a metal oxide hydroxide as a main component, contains substantially no single metal and alloy, and is a diamagnetic substance or a paramagnetic substance; and a ferromagnetic material part that is present inside the inorganic matrix part, directly bonds with the inorganic substance making up the inorganic matrix part, and is made from a ferromagnetic substance. In the inorganic matrix part, particles of the inorganic substance are continuously present, and the inorganic matrix part has a larger volume ratio than that of the ferromagnetic material part.