Transparent Nanocomposite Ceramics via Core/Shell Nanoparticles
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Solution Overview
Problem
Current methods for producing bulk nanocrystalline ceramics with nano-scale elements are limited by residual porosity, incorporation of foreign substances, and inability to maintain nanoscale structure, especially when achieving grain sizes below 50 nm, which restricts the material's properties and applications.
Innovation Solution
The process involves creating core/shell or core/multi-shell nanoparticles and sintering them using Enhanced High Pressure Sintering (EHPS) at temperatures below 0.7 Tm under high pressure, ensuring a pristine surface and preventing grain coarsening, resulting in fully dense nanocomposite ceramics with retained nanostructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sintering methods are used to produce bulk nanocrystalline ceramics, then the material can be consolidated into a bulk form, but residual porosity remains and the nanoscale structure is lost due to grain coarsening
Solution Approach 1:
The patent applies preliminary action by pre-coating nanoparticles with shell materials before sintering. This pre-preparation prevents grain coarsening during the sintering process while enabling full densification, thereby resolving the contradiction between retaining nanoscale structure and eliminating porosity.
Solution Approach 2:
The patent changes the sintering parameters by using enhanced high pressure sintering (EHPS) at temperatures below 0.7 Tm under high pressure. This parameter modification allows the material to densify completely while preventing grain growth, thus eliminating porosity without losing the nanoscale structure.
2Strength
If grain size is reduced to below 50 nm to enhance mechanical properties, then hardness and strength increase, but the material becomes difficult to process and maintain as a bulk material
Solution Approach 1:
The patent changes the processing parameters by implementing enhanced high pressure sintering at temperatures below 0.7 Tm under high pressure. This enables the consolidation of ultrafine grains below 50 nm into bulk materials without grain coarsening, resolving the contradiction between achieving high hardness and maintaining ease of manufacture.
Solution Approach 2:
The patent creates composite nanoparticles with core/shell structures where the shell material prevents grain coarsening during processing. This composite approach allows the bulk material to be processed while maintaining ultrafine grain sizes for enhanced hardness.
3Manufacturing precision
If shell coating is applied to nanoparticles to prevent grain coarsening, then nanoscale structure is preserved, but foreign substances are incorporated into the material
Solution Approach 1:
The patent changes the processing parameters by using enhanced high pressure sintering at temperatures below 0.7 Tm. This temperature control allows the removal or transformation of shell materials without grain coarsening, thus preserving nanoscale structure while eliminating foreign substance incorporation.
Solution Approach 2:
The patent applies the discarding principle by removing or transforming the shell coating materials during the enhanced sintering process. The shell materials serve their protective function during processing and are then discarded or integrated, leaving no harmful foreign substances in the final material.
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 method produces transparent nanocomposite ceramics with enhanced mechanical and optical properties, achieving fully dense bulk materials with nanoscale properties and structure, overcoming the limitations of existing techniques by eliminating porosity and maintaining the initial nanostructure.
Implementation Method 1
The green compact is then placed in a high-pressure device and is sintered at a temperature below conventional sintering temperatures to produce a transparent nanocomposite ceramic solid or other solid bulk material having a retained nanostructure or nano-heterostructure corresponding to the nanostructure of the constituent nanoparticles.
Implementation Method 2
consolidating core/shell and core/multi-shell nanoparticles of different ceramic materials into fully dense nanocomposite ceramics and other solid bulk materials
Implementation Method 3
sintered at a temperature below conventional sintering temperatures to produce a transparent nanocomposite ceramic solid
Data Source
AI summary
A method for making transparent nanocomposite ceramics and other solid bulk materials from nanoparticle powders and transparent nanocomposite ceramics and other solid bulk materials formed using that method. A nanoparticle powder is placed into a reaction chamber and is treated to produce a clean surface powder. The clean surface powder is coated with a second material by means of p-ALD to produce core/shell or core multi shell nanoparticles having a coating or coatings of a other material surrounding the nanoparticle. The core/shell nanoparticles are cleaned and formed into green compact which is sintered to produce a transparent nanocomposite ceramic or other solid bulk material consisting of nanoparticles or core/shell nanoparticles uniformly embedded in a matrix of a different material, particularly in a matrix of a different ceramic material, formed by outer shell of initial core/shell. All steps are performed without exposing the material to the ambient.