Planetary Rotation Fluidized Apparatus for Nanoparticle ALD
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Solution Overview
Problem
Nanoparticles with large specific surface areas tend to agglomerate and are difficult to coat uniformly due to non-uniform interstitials in particle beds, limiting precursor diffusion and resulting in long cycle times and low precursor utilization in atomic layer deposition processes.
Innovation Solution
A device utilizing planetary fluidization with a motor, reaction chamber, planet carrier, and cartridge, which employs radial centrifugal and axial vertical fluidization to break agglomerates and ensure uniform distribution of nanoparticles, combined with a magnetic fluid seal and adjustable gas flow, allowing for precise control of precursor exposure and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional liquid-phase coating techniques are used, then coating process is simple, but residue organic surfactants remain and thickness control is complex
Solution Approach 1:
The patent replaces liquid-phase coating with vapor-phase atomic layer deposition (ALD). The mechanical/chemical liquid coating process is substituted by vapor-phase precursor deposition, eliminating organic surfactant residues while achieving atomic-scale thickness control through self-limited chemisorption reactions.
Solution Approach 2:
The patent changes the phase parameter from liquid to vapor for the coating process. By using vapor-phase precursors in ALD, the system achieves precise thickness control at the atomic scale while avoiding the contamination issues associated with liquid-phase organic coatings.
2Manufacturing precision
If ALD is used for particle surface modification, then uniform and conformal nanoscale films are deposited with precise thickness control, but large surface area and non-uniform interstitials limit precursor diffusion resulting in long cycle time and low precursor utilization
Solution Approach 1:
The patent introduces dynamic fluidization by rotating the particle bed during ALD deposition. This dynamic approach transforms the static particle bed into a fluidized state, enhancing precursor diffusion throughout the particle bed while maintaining uniform film deposition. The rotation creates continuous movement that improves mass transport without sacrificing film quality.
Solution Approach 2:
The patent uses gas flow to fluidize the particle bed during deposition. By introducing carrier gas flow and rotating the particles, the system achieves pneumatic fluidization that enhances precursor penetration and diffusion throughout the particle bed, significantly improving precursor utilization and reducing cycle time while maintaining conformal coating quality.
3Stability of the object's composition
If nanoparticles are fluidized by vibrations, then particle dispersion is improved, but coating uniformity and saturation for large quantities of particles are insufficient
Solution Approach 1:
The patent replaces simple vibration with planetary rotation and fluidization. This dynamic mechanism creates both radial centrifugal forces and axial vertical fluidization, generating superior particle dispersion and uniform coating saturation for large quantities of particles. The combined motion patterns ensure all particle surfaces are equally exposed to precursors.
Solution Approach 2:
The patent adds rotational dimensions to the fluidization process. By implementing planetary rotation with both radial and axial motion components, the system moves beyond single-dimensional vibration to multi-dimensional particle movement, achieving superior dispersion and coating uniformity across large particle quantities.
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 device achieves improved coating uniformity and efficiency by applying super-gravity forces to break agglomerates and ensure uniform fluidization, increasing deposition ratio and batch processing ability for nanoparticles.
Implementation Method 1
The radial centrifugal fluidization arising from rotation and revolution of particle cartridge increases the shear force to break the agglomerates apart
Implementation Method 2
axial vertical fluidization combining the planetary movement is capable of eliminating the non-uniform distribution of nanoparticles inside the cartridge
Implementation Method 3
atomic layer deposition (ALD) based on self-limited chemisorption mechanism is able to deposit uniform and conformal nanoscale films
Implementation Method 4
The motor is connected to the planet carrier via a magnetic fluid seal device
Data Source
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AI summary
This disclosure provides a device for nanoparticles' atomic layer decoration based on planetary fluidization, comprising a motor (2), a reaction chamber, a planet carrier (13), a cartridge (6), and gas manifolds. Before coating, the nanoparticles are firstly put into the cartridges, and then the cartridges are settled onto the hollow planet wheels (9). The planetary mechanism drives the cartridge to conduct planetary movement. Along the radial direction, the nanoparticles in the cartridge suffer the centrifugal force generated by the revolution, and therefore intend to move outwards and stack on the walls of the cartridges which locate on the connecting line from the revolution axis to spin axis. In the meantime, the circumferential friction force generated by the spin of cartridges compels the nanoparticles to rotate inside the cartridge, achieving centrifugal fluidization. In the axis direction of said planet wheel (9), the nanoparticles are fluidized by the axial vertical fluidizing gas, and exhibit uniform fluidization as traditional vertical fluidized bed. During modification process, precursor gas and purge gas alternatively enter the cartridge through the planet carrier, and the precursor molecules are absorbed on the surface of the nanoparticles upon pulse stage, forming an atomic layer film. Repeating the deposition cycles will finally obtain the desired coating thickness. The coupling of the centrifugal and vertical fluidization exerts shear force 30 times greater than gravity on the agglomerates, breaks them apart, and overcome the axial non-uniform distribution in the centrifugal fluidized bed, realizing more uniform fluidization and coating for each individual nanoparticle. In addition, the device of the invention can effectively improve nanoparticles' coating percentage and uniformity, and significantly increase the coating efficiency with high batch processing ability.