Nanometer-Size Spherical Particle Production via Plasma Treatment
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Solution Overview
Problem
Conventional methods fail to produce nanometer-size spherical particles with a sphericity of about −10% to +10%, which are essential for industrial applications due to their superior properties and high yield, as existing methods result in particles with inferior sphericity and amorphous structures, limiting their practical use.
Innovation Solution
The production of nanometer-size spherical particles with a sphericity of −10% to +10% is achieved through a two-step process involving the formation of intermediate micrometer-size spherical particles followed by plasma treatment, which converts them into nanometer-size particles with a composite structure of homogenously mixed amorphous and crystalline regions, ensuring high sphericity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional methods are used to produce nanometer-size particles, then particle size is reduced, but sphericity deteriorates and particles become amorphous
Solution Approach 1:
The invention applies preliminary action by first forming micrometer-size spherical particles with good sphericity through centrifugal granulation, then subsequently reducing them to nanometer size through plasma treatment. This two-step approach ensures that the spherical shape is established before size reduction, preventing the sphericity deterioration that occurs when size is reduced directly in conventional methods.
Solution Approach 2:
The invention replaces mechanical size reduction methods with plasma treatment to achieve nanometer size reduction. The plasma treatment uses ion bombardment and thermal effects to erode the micrometer-size spherical particles, converting them to nanometer size while preserving their spherical shape and even forming a composite structure with crystalline regions, unlike conventional mechanical methods that produce amorphous particles with poor sphericity.
2Length of moving object
If conventional methods are used to produce nanometer-size particles, then particle size is reduced, but crystal structure is lost and amorphous structure forms
Solution Approach 1:
The invention replaces mechanical size reduction with plasma treatment, which uses ion bombardment and controlled thermal effects to reduce particle size. This plasma process selectively removes material while preserving and even enhancing crystalline structure, forming a composite structure with both amorphous and crystalline regions. Conventional mechanical methods lack the controlled energy input needed to maintain crystal structure during size reduction.
Solution Approach 2:
The plasma treatment process induces phase transitions in the material during size reduction. The ion bombardment and thermal effects cause localized melting and rapid solidification, which can form crystalline regions within the particles. This phase transition mechanism allows the formation of a composite structure with both amorphous and crystalline regions, maintaining structural stability while achieving nanometer size.
3Length of moving object
If micrometer-size spherical particles are plasma-treated, then nanometer-size particles are produced, but production complexity increases
Solution Approach 1:
The invention segments the particle production process into two distinct stages: (1) centrifugal granulation to form micrometer-size spherical particles with good sphericity, and (2) plasma treatment to reduce size to nanometer scale while preserving structure. This segmentation allows each process to be optimized independently, with the first stage focusing on shape formation and the second on size reduction, making the overall complex process more controllable and manufacturable.
4Reliability
If nanometer-size spherical particles with high sphericity are produced, then industrial applicability improves, but manufacturing difficulty increases
Solution Approach 1:
The plasma treatment process exhibits self-service characteristics where the ion bombardment automatically adjusts to the particle morphology. The plasma erodes the particles in a way that maintains and even enhances their spherical shape, with the process itself serving to both size-reduce and shape-refine the particles simultaneously. This self-adjusting mechanism reduces the need for additional shaping operations and makes high-sphericity nanometer particles more manufacturable.
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 results in nanometer-size spherical particles with improved properties, suitable for manufacturing high-efficiency devices such as fine wires, semiconductor photoelectric transducers, and luminescent materials, offering enhanced performance and industrial applicability.
Implementation Method 1
collide with argon ions in a plasma swirl
Implementation Method 2
collide with argon ions in a plasma swirl to form spherical particles having a nanometer size
Implementation Method 3
atomizing the molten starting material into fine droplets by the action of centrifugal force
Implementation Method 4
bringing the fine droplets into contact with an inert atmosphere to quench the fine droplets
Implementation Method 5
collide with argon ions in a plasma swirl
Implementation Method 6
The spherical particles of the intermediate product are converted into a substantially complete spherical shape
Data Source
AI summary
The present invention provides a method for producing nanometer-size spherical particles. The method includes a first step for producing intermediate spherical particles. The intermediate spherical particles include a polycrystalline or single-crystalline region, having a particle size of 1 to 300 μm. The method of the present invention further includes a second step for producing final spherical particles. The second step uses a swirling plasma gas flow having the central axis thereof, the central axis running through an area between an anode and a cathode of a plasma generator. The intermediate spherical particles are discharged along the axis to subject the intermediate spherical particles to a plasma atmosphere of the area to form the final spherical particles.