Diamond Powder Purification via Plasma Cleaning and Thermal Cracking
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Solution Overview
Problem
Diamond powder is often contaminated with carbon and metal impurities, particularly from the solvent-catalyst method, which are difficult to remove due to diamond's hardness, limiting its purity and usability for various applications.
Innovation Solution
A plasma cleaning treatment is used to remove carbon contaminants and expand metal inclusion contaminants, causing them to crack and expose the metal impurities, followed by chemical or electrochemical treatments to remove these impurities, resulting in increased diamond purity and potentially smaller grain sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diamond grains are crushed to access encapsulated contaminants, then contaminant removal is improved, but processing difficulty and cost increase due to diamond's extreme hardness
Solution Approach 1:
The patent applies preliminary action by using plasma treatment and thermal expansion before any crushing or contaminant removal process. The plasma cleaning process and thermal cycling cause metal inclusions to expand and crack the diamond grains from within, pre-exposing contaminants to the surface before any mechanical removal is attempted. This preliminary cracking action makes subsequent contaminant removal much easier without requiring extreme crushing forces.
Solution Approach 2:
The patent replaces mechanical crushing with plasma-based and thermal-based mechanisms. Instead of using mechanical force to crush diamond grains and expose contaminants, the invention uses plasma cleaning to remove carbon contaminants and thermal expansion to crack metal inclusions from within. This substitution of mechanical systems with plasma and thermal fields resolves the contradiction by avoiding the need to mechanically process extremely hard diamond material.
2Ease of manufacture
If surface cleaning methods are used, then processing ease is improved, but contaminant removal is limited to surface only and internal contaminants remain
Solution Approach 1:
The patent applies the nested doll principle through multi-stage processing where plasma cleaning is nested within thermal treatment, which is nested within chemical or electrochemical cleaning. The plasma cleaning process is performed first to remove carbon contaminants, then thermal expansion cracks metal inclusions, and finally chemical or electrochemical processes remove the exposed metal contaminants. This nested sequence of treatments ensures both surface and internal contaminants are removed while maintaining processing feasibility.
Solution Approach 2:
The patent uses preliminary plasma cleaning action to remove carbon contaminants and create surface exposure before applying chemical or electrochemical treatments. This preliminary action prepares the diamond grains by removing the outer carbon layer and exposing internal metal contaminants, making them accessible to subsequent chemical or electrochemical cleaning processes without requiring extreme mechanical crushing.
3Manufacturing precision
If plasma cleaning is used to remove carbon contaminants, then carbon contaminant removal is improved, but metal inclusions must be separately addressed through thermal expansion
Solution Approach 1:
The patent merges multiple functions into a unified plasma treatment process. The plasma cleaning process simultaneously removes carbon contaminants from the diamond surface and prepares the grain structure for subsequent thermal treatment. By combining carbon removal and preparation for metal inclusion removal in a sequential plasma-thermal process, the invention reduces overall process complexity compared to treating contaminants in completely separate stages.
Solution Approach 2:
The patent maintains continuity of useful action by seamlessly transitioning from plasma cleaning to thermal expansion treatment. The plasma cleaning process continuously removes carbon contaminants while the thermal treatment immediately follows to expand metal inclusions. This continuous sequence of treatments without interruption or intermediate processing steps maintains process efficiency and reduces complexity by eliminating idle time and additional processing equipment.
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 process effectively increases diamond purity, de-aggregates grains, and produces smaller nanometer-sized diamond grains, addressing the limitations of existing methods that primarily focus on surface purification and are inefficient for removing internal contaminants.
Implementation Method 1
removing carbon contaminants from diamond grains in the diamond by a plasma cleaning process
Implementation Method 2
causing expansion of metal inclusion contaminants, which cracks diamond grains from within
Implementation Method 3
removing metal contaminants from the diamond in a chemical or electrochemical cleaning process
Data Source
AI summary
The present disclosure relates a method of purifying diamond by removing carbon contaminants from diamond grains in the diamond by a plasma cleaning process at a temperature at which metal inclusion contaminants in the diamond grains crack the diamond grains from within, and removing metal contaminants from the diamond in a chemical or electrochemical cleaning process.