Boron Carbide Nanoparticle Synthesis via Gel Precursor Sintering

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Solution Overview

Problem

Conventional methods for producing boron carbide particles at high temperatures result in energy inefficiency, chemical contamination, and high costs due to agglomeration and the need for milling, as well as the production of low-purity boron carbide as a by-product.

Innovation Solution

A method involving a fluid mixture of elemental boron, glycerin, and carboxylic acids with specific molar ratios, heated to form borate ester bonds, then solidified and sintered at lower temperatures to produce boron carbide nanoparticles without the need for milling, minimizing energy consumption and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature carbothermal processes are used to produce boron carbide particles, then boron oxide reduction and carburization occur, but energy consumption increases and carbon source loss occurs

Engineering Contradiction:
Improveboron carbide production efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter from conventional high temperatures (1900°C or higher) to lower temperatures (100-800°C) by using a gel precursor method. This parameter change enables boron carbide formation while significantly reducing energy consumption and preventing carbon source loss that occurs at high temperatures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary action by forming a gel precursor containing boron and carbon sources before the actual sintering process. This gel structure is prepared in advance through chemical reactions at lower temperatures, and then undergoes controlled sintering to form boron carbide, avoiding the need for high temperature carbothermal reduction.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If high temperature processes are used for boron oxide reduction, then boron carbide forms, but excessive agglomeration occurs requiring milling

Engineering Contradiction:
Improveboron carbide formationVSAvoidmilling process requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the temperature parameter to lower ranges (100-800°C) during the gel formation and sintering processes. This parameter change prevents excessive agglomeration that occurs at high temperatures, producing boron carbide particles that do not require subsequent milling, thereby simplifying the overall process.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If milling is performed to separate agglomerated particles, then particle separation occurs, but chemical contamination increases due to abrasive wear

Engineering Contradiction:
Improveparticle separationVSAvoidchemical contamination
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the temperature parameter to lower ranges, eliminating the need for milling operations. By controlling the sintering temperature and gel formation conditions, boron carbide particles form with appropriate dispersion without excessive agglomeration, thereby avoiding the chemical contamination that would result from milling operations.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If elemental boron and carbon powders are used to avoid boron oxide reduction, then production costs increase due to high starting material values

Engineering Contradiction:
Improveavoidance of reduction processVSAvoidstarting material cost
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The invention changes the temperature parameter to lower ranges (100-800°C) and uses a gel precursor method with boron oxide and carbon sources. This approach avoids the need to use expensive elemental boron and carbon powders, as the gel precursor can be formed from more cost-effective boron oxide and carbon-containing compounds.

Inventive Principle:
Principle #35Parameter changes

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 enables the production of highly crystalline boron carbide nanoparticles with controlled size and morphology, reducing costs and chemical contamination, and eliminating the need for milling, while achieving efficient reaction kinetics and enhanced crystallinity.

Implementation Method 1

heating of said fluid mixture thereby obtaining a first mid-product in the form of a gel comprising borate ester bonds

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

solidification of said first mid-product by heating the reaction product, thereby obtaining a second mid-product in solid form

Methodology Applied
Scientific EffectPhase Change: Phase Change

Implementation Method 3

sintering said second mid-product, thereby obtaining boron carbide in the form of particles

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS11912578B2Low-temperature method for boron carbide production
Publication Date: 2024.02.27 SABANCI UNIVERSITY

AI summary

A production method of boron carbide nano-sized particles and/or submicron particles includes the following sequential steps: obtention of a fluid mixture including elemental boron, glycerin and one or more carboxylic acid, wherein a molar ratio of glycerin to the one or more carboxylic acids is within a range between 10:1 and 10:7.5. Heating of the fluid mixture to obtain a first mid-product in a form of a gel including borate ester bonds. Solidification of the first mid-product by heating a reaction product to obtain a second mid-product in solid form. Sintering the second mid-product to obtain boron carbide in a form of particles.