Crystal Oriented Ceramics via Composite Particle Orientation
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Solution Overview
Problem
Existing methods for producing crystal oriented ceramics require strong magnetic fields, making them inefficient for mass production and unsuitable for aligning crystal axes of hard magnetization, as they necessitate rotating the material in a magnetic field, which is not conducive to batch production.
Innovation Solution
A process involving composite particles with magnetic anisotropy and seed particles is used, where the seed particles have a lower magnetic susceptibility anisotropy, allowing for orientation in a static magnetic field of 0.1 tesla or greater, enabling the production of dense crystal oriented ceramics with aligned crystal axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a strong magnetic field (1 T or greater) is applied to achieve crystal orientation, then the orientation can be achieved, but the orientation time becomes extremely long due to small magnetic torque
Solution Approach 1:
The patent uses composite particles consisting of magnetic particles (with high magnetic susceptibility anisotropy) and non-magnetic particles (with low magnetic susceptibility anisotropy). The magnetic particles experience strong magnetic torque and orient quickly along the magnetic field direction, while the non-magnetic particles have their crystal axes aligned with their major axes. Through sintering, the crystal axes of the non-magnetic particles become oriented parallel to the magnetic field direction, achieving rapid crystal orientation without requiring extremely long orientation times.
Solution Approach 2:
The magnetic particles act as intermediaries that experience the magnetic field directly and transfer their orientation state to the non-magnetic particles through the composite structure. The magnetic particles with high magnetic susceptibility anisotropy serve as a mediator that converts magnetic field energy into mechanical orientation, which is then transferred to the target non-magnetic particles during sintering.
2Productivity
If a static magnetic field is applied for orientation, then the process is suitable for mass production, but crystal axes of hard magnetization cannot be aligned in one direction
Solution Approach 1:
The patent applies different properties to different parts of the composite particle system. Magnetic particles are assigned high magnetic susceptibility anisotropy to respond to the static magnetic field, while non-magnetic particles are assigned low magnetic susceptibility anisotropy and anisotropic shapes where the crystal axis corresponds to the major axis. This local differentiation allows the magnetic particles to drive orientation in a static field while the non-magnetic particles achieve the desired crystal axis alignment.
Solution Approach 2:
The patent changes the magnetic susceptibility anisotropy parameter between the two types of particles. Magnetic particles have high magnetic susceptibility anisotropy to experience sufficient magnetic torque in a static magnetic field, while non-magnetic particles have low magnetic susceptibility anisotropy (≤1/10 of magnetic particles) to minimize interference and allow their crystal structure to dominate the orientation behavior. This parameter differentiation enables static field orientation for mass production while achieving proper crystal axis alignment.
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 allows for the production of dense crystal oriented ceramics with aligned crystal axes using a static magnetic field, enhancing production efficiency and suitability for mass production while reducing costs.
Implementation Method 1
particles having magnetic anisotropy (A) which have an anisotropy of magnetic susceptibility
Implementation Method 2
disposing the slurry in a static magnetic field of 0.1 tesla (T) or greater
Data Source
AI summary
A production process for a crystal oriented ceramics includes: a first step of preparing composite particles formed of particles having magnetic anisotropy having magnetic susceptibility anisotropy and seed particles having magnetic susceptibility anisotropy less than or equal to 1/10 of the magnetic susceptibility anisotropy of the particles having magnetic anisotropy and are formed of an inorganic compound having an anisotropic shape in which a crystal axis intended to be corresponds to a minor axis or a major axis; a second step of adding raw material powder including the composite particles to a solvent to prepare a slurry a third step of preparing a green compact by disposing the slurry in a static magnetic field of ≥0.1 tesla and drying the slurry in a state in which crystal axes of the seed particles in a major axis direction are in one direction; and a fourth step of sintering the green compact.