Cerium Boride Powder Synthesis via Room-Temperature Ball Milling
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Solution Overview
Problem
Existing methods for synthesizing cerium boride powder face challenges such as high toxicity, long synthesis times, large crystal grain sizes, and the inability to produce powders with small crystal grain sizes suitable for catalytic applications, particularly due to high temperatures and inert gas atmospheres.
Innovation Solution
A method involving high-energy ball milling of mixed powders containing cerium chloride or oxide, magnesium hydride or magnesium, and boron oxide at room temperature, followed by selective deposition in an acidic solution to produce cerium boride powder with a crystal grain size of about 20 nm and a particle size of up to 5 μm, using a ball milling process in an air or inert gas atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature vapor deposition is used to synthesize CeB6, then monocrystalline nanowires can be obtained, but the process requires high temperature (1125°C) and uses harmful BCl3 gas
Solution Approach 1:
The invention changes the temperature parameter from high temperature (1125°C) to room temperature, and changes the chemical form from BCl3 gas to solid boron powder, eliminating the harmful gas while achieving CeB6 synthesis through ball milling and thermal treatment
Solution Approach 2:
The invention uses readily available solid reagents (cerium chloride powder, boron powder, magnesium powder) instead of expensive and hazardous gaseous reagents (BCl3), making the process safer and more economical while achieving the desired product
2Loss of time
If medium or low temperature synthesis is used for CeB6, then synthesis time becomes very long (12-48 hours), but if high temperature is used, then crystal grain size increases
Solution Approach 1:
The invention performs preliminary ball milling to mix and pre-react the reagents at room temperature before thermal treatment, which activates the materials and reduces the subsequent heating time required, thus avoiding both long synthesis times and excessive crystal grain growth
Solution Approach 2:
The invention uses excess magnesium powder that continuously reacts with boron oxide during heating, maintaining a reducing atmosphere that promotes CeB6 formation while limiting crystal grain growth, achieving both speed and precision
3Manufacturing precision
If ball milling is used to reduce crystal grain size, then small crystal grains can be obtained, but synthesis must be performed in inert gas atmosphere
Solution Approach 1:
The invention uses excess magnesium powder that acts as a self-contained protective atmosphere during ball milling and heating, eliminating the need for external inert gas protection while preventing oxidation and maintaining reaction integrity
Solution Approach 2:
The invention changes the atmosphere parameter from requiring external inert gas to using a self-generated protective atmosphere through excess magnesium, simplifying the equipment and operational complexity while achieving the desired fine crystal grain size
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 allows for the economical preparation of cerium boride powder with a small crystal grain size and appropriate particle size, suitable for catalytic applications, while avoiding the use of harmful gases and high temperatures, and achieving a high specific surface area for enhanced catalytic performance.
Implementation Method 1
a second step for generating composite powder including cerium boride (CexBy) and at least one selected from among magnesium oxide (MgO) and magnesium chloride (MgCl2), by causing reaction in the mixed powder at room temperature based on a ball milling process
Implementation Method 2
a third step for selectively depositing cerium boride powder by dispersing the composite powder in a solution
Data Source
AI summary
A method of preparing cerium boride powder, according to the present invention, includes a first step for generating mixed powder by mixing at least one selected from among cerium chloride (CeCl3) powder and cerium oxide (CeO2) powder, at least one selected from among magnesium hydride (MgH2) powder and magnesium (Mg) powder, and boron oxide (B2O3) powder, a second step for generating composite powder including cerium boride (CexBy) and at least one selected from among magnesium oxide (MgO) and magnesium chloride (MgCl2), by causing reaction in the mixed powder at room temperature based on a ball milling process, and a third step for selectively depositing cerium boride powder by dispersing the composite powder in a solution.