Imine-Coated Noble Metal Nanoparticles for Low-Temperature Sintering
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Solution Overview
Problem
Existing noble metal fine particles, particularly gold, face challenges with agglomeration and sedimentation, leading to instability in dispersion and the need for high sintering temperatures, which contradicts the development of low-temperature sinterable materials.
Innovation Solution
A noble metal fine particle with an imine compound on its surface, characterized by an amine/imine ratio (A/I ratio) of 1 or less, allows for high dispersion stability and low-temperature sinterability, achieving a dense sintered body at 300°C or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If alkyl amine is used as a protective agent to enhance dispersion stability, then dispersibility is improved, but sintering temperature is forced to be increased
Solution Approach 1:
The patent changes the chemical structure of the protective agent from conventional alkyl amine to a compound containing both amine and carboxylic acid functional groups. This parameter change in molecular structure allows the protective agent to provide sufficient steric hindrance for dispersion stability while having lower thermal stability, enabling complete removal at lower sintering temperatures (200-400°C) compared to conventional alkyl amines that require temperatures above 400°C
Solution Approach 2:
The protective agent used in this patent is a composite molecular structure containing both amine and carboxylic acid functional groups within the same molecule. This composite structure combines the dispersion-stabilizing capability of amine groups with the low thermal stability characteristic of carboxylic acid groups, achieving both good dispersibility and low-temperature sinterability simultaneously
2Stability of the object's composition
If long-chain alkyl amine is used to enhance protective force, then dispersibility is improved, but agglomeration and sedimentation still occur in high concentration dispersions
Solution Approach 1:
The patent changes the protective agent from long-chain alkyl amine to a compound with amine and carboxylic acid groups that has optimal molecular weight and structure. This parameter change allows the protective agent to provide sufficient steric hindrance and electrostatic repulsion even at high particle concentrations, preventing agglomeration and sedimentation while maintaining excellent dispersibility. The carboxylic acid groups also provide additional interaction mechanisms that enhance stability at high concentrations
3Stability of the object's composition
If mixed protective film of carboxylic acid and amine is used to avoid agglomeration, then dispersibility is improved, but removal of protective film requires sintering at relatively higher temperatures for a long time
Solution Approach 1:
The patent merges the amine and carboxylic acid functional groups into a single protective agent molecule rather than using them as separate components. This merging creates a unified protective film that provides both steric hindrance and electrostatic repulsion simultaneously. The key advantage is that the carboxylic acid groups have lower thermal stability and can be completely removed at lower temperatures (200-400°C) compared to conventional mixed films that require temperatures above 400°C for extended periods
Solution Approach 2:
The patent changes the thermal stability parameter of the protective film by using carboxylic acid groups instead of conventional high-thermal-stability protective agents. This parameter change allows the protective film to be completely removed at lower sintering temperatures (200-400°C) and shorter times, eliminating the need for high-temperature long-duration sintering processes while still maintaining excellent dispersion stability during storage and application
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 imine compound stabilizes the noble metal particles, enabling high dispersibility in various solvents and facilitating the formation of a dense sintered body at lower temperatures, suitable for conductor formation and catalyst applications.
Implementation Method 1
an imine compound generated by dehydration and condensation of a carbonyl compound and primary amine is held on the surface
Implementation Method 2
sintering at temperatures of 300° C or less, and a cyclic alcohol is used as a disperse medium for enhanced stability
Data Source
AI summary
A noble metal fine particle herein disclosed includes a noble metal element as a main constituent metal element. An imine compound is held on a surface, and an amine/imine ratio (A/I ratio) of an area ratio of a peak area of the imine compound and a peak area of an amine compound determined in pyrolysis GCMS analysis with a pyrolysis temperature of 300° C. is 1 or less.