Axial Injection DC Plasma with Laser for Coating Uniformity
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Solution Overview
Problem
Conventional direct current plasma processing suffers from temperature non-uniformity and deposition inefficiency due to radial injection, leading to suboptimal coating quality, especially in nanomaterial synthesis, and challenges in melting high melting point materials and achieving uniform coating structures.
Innovation Solution
The modified direct current plasma apparatus employs axial injection of precursors through the cathode or an axial injector, and incorporates a laser beam for in-situ hybrid processing, allowing for improved temperature control and coating uniformity, enabling the synthesis of various nanomaterials and complex coatings for applications like solar, biomedical, and fuel cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If radial injection method is used in DC plasma processing, then precursor materials can be introduced into the plasma jet, but temperature non-uniformity occurs causing particles at different positions to experience different temperatures
Solution Approach 1:
The patent inverts the conventional radial injection approach by implementing axial injection through the cathode. Instead of injecting precursors from the side (radial), the system now introduces them through the center axis (axial) via the cathode, fundamentally changing the injection geometry to achieve uniform temperature exposure throughout the plasma jet.
Solution Approach 2:
The patent applies local quality by creating a central channel through the cathode that allows precise control of precursor injection location. This localized injection path ensures that all precursor materials pass through the same controlled environment and experience uniform thermal conditions before deposition.
2Quantity of substance
If radial injection is used, then precursor materials are introduced into plasma jet, but particles achieve lower velocity due to direction change from radial to axial
Solution Approach 1:
The patent inverts the injection direction from radial to axial, eliminating the need for particles to change direction mid-flight. By introducing precursors axially through the cathode center, particles maintain their forward momentum and achieve higher velocities directly into the plasma jet without the directional transition losses inherent in radial injection.
3Productivity
If external radial injection is used, then precursor materials are fed into plasma jet boundary, but interaction time with jet is shorter preventing complete melting of high melting point materials
Solution Approach 1:
The patent applies preliminary action by pre-positioning the precursor injection point at the cathode center, upstream of the plasma jet formation. This allows precursors to be introduced early in the process and given sufficient residence time to undergo complete melting and reaction before deposition, rather than being injected late at the jet boundary.
Solution Approach 2:
By inverting the injection location from external radial (at jet boundary) to internal axial (through cathode center), the system extends the interaction path length. Precursors now travel through the entire plasma jet duration, maximizing exposure time for melting and reaction of high melting point materials.
4Manufacturing precision
If conventional DC plasma processing is used, then coatings can be deposited on substrate, but coating density and uniformity are suboptimal
Solution Approach 1:
The patent inverts the injection geometry from radial to axial through cathode, creating a more uniform and controlled deposition process. This fundamental geometric inversion improves coating density and uniformity by ensuring all particles experience consistent thermal and flow conditions throughout their trajectory.
Solution Approach 2:
The patent changes key process parameters by implementing axial injection through the cathode, which fundamentally alters the flow dynamics, temperature distribution, and particle trajectory. These parameter changes lead to improved coating quality without requiring complex additional system components.
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 enhances coating density, uniformity, and deposition efficiency, allowing for the successful synthesis of high melting point materials and complex coatings with improved properties, such as those required for solar cells, fuel cells, and biomedical applications, while extending cathode life and reducing defects.
Implementation Method 1
An electrical arc is established and it extends from the cathode 112 to the anode 114 and generates the plasma gas to form a hot gas jet 118
Implementation Method 2
In the jet, where the temperature is on the order of 10,000 K, the material is melted and propelled towards a substrate
Implementation Method 3
incorporates a laser beam for in-situ hybrid processing, allowing for improved temperature control and coating uniformity
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A method and apparatus for forming layers on a target. The apparatus and method employ a direct current plasma apparatus to form at least one layer using a plasma jet containing precursors. In some embodiments, the direct current plasma apparatus utilizes axial injection of the precursors through the cathode (in an upstream and/or downstream configuration) and/or downstream of the anode. In some embodiments, the direct current plasma apparatus can comprise a laser source for remelting the layer using a laser beam to achieve insitu densification thereof.