Silver-Based Electrical Contact Material Uniform Carbon Coating
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Solution Overview
Problem
Traditional methods for preparing silver-based electrical contact materials, such as powder metallurgy and high energy ball milling, result in inhomogeneous mixing, agglomeration, and contamination, leading to poor mechanical and electrical properties, and the addition of diamond increases production costs without achieving uniform dispersion.
Innovation Solution
A method involving a carbonaceous mesophase solution with a silver source, where chemical silver powder is immersed and mixed with the mesophase, followed by solvent removal and heat treatment, achieving uniform carbon coating and nanoscale dispersion of carbon, including diamond, in a silver-based electrical contact material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional powder metallurgy or high energy ball milling is used to mix silver powder and graphite powder, then the mixing process is simple and straightforward, but the mixing is inhomogeneous and leads to powder agglomeration
Solution Approach 1:
The patent introduces a liquid medium (water or alcohol) as an intermediary to facilitate homogeneous mixing of silver powder and graphite powder. The liquid medium allows the powders to disperse uniformly during stirring, preventing agglomeration. After mixing, the liquid is removed by drying, leaving uniformly distributed powders without the complexity of traditional ball milling equipment.
2Strength
If diamond is added to silver-based electrical contact material to improve wear resistance, then the mechanical properties are optimized, but the production cost greatly increases
Solution Approach 1:
The patent replaces expensive diamond particles with graphite powder, which is a much cheaper carbonaceous material. While graphite has different properties than diamond, it still provides wear resistance benefits when uniformly dispersed in the silver matrix, achieving acceptable wear resistance at significantly lower production cost.
Solution Approach 2:
The patent changes the form and distribution parameters of carbonaceous material by using fine graphite powder instead of diamond particles. The uniform dispersion of graphite powder at the micro-scale, achieved through liquid medium mixing, compensates for the lower intrinsic hardness of graphite compared to diamond, providing adequate wear resistance for electrical contact applications.
3Manufacturing precision
If carbonaceous material is added to improve overall performance, then the material properties are enhanced, but carbon exhibits poor coating and poor invasion with respect to atomized silver powder
Solution Approach 1:
The patent uses liquid medium (water or alcohol) as an intermediary to improve the coating and invasion of carbonaceous material on silver powder. The liquid medium allows both powders to wet and disperse uniformly during stirring, ensuring good coating uniformity. The liquid facilitates intimate contact between carbonaceous material and silver powder surfaces, achieving reliable material performance.
4Productivity
If traditional mixing methods are used, then the process is simple, but contamination with ball milling medium occurs due to relatively long treatment time
Solution Approach 1:
The patent replaces the mechanical ball milling system with a simple stirring process in liquid medium. This substitution eliminates the need for ball milling media, thereby preventing contamination from ball milling medium. The liquid medium stirring achieves homogeneous mixing much faster than traditional ball milling, significantly reducing processing time and improving productivity.
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 method produces a silver-based electrical contact material with excellent mechanical wear resistance and electrical properties, reducing production costs and avoiding agglomeration issues, with carbon uniformly dispersed in a nanometer scale and diamond generated in situ during sintering.
Implementation Method 1
adding a silver source to the carbonaceous mesophase solution under stirring to obtain a mixture
Implementation Method 2
removing a solvent from the mixture, thereby obtaining a solid
Implementation Method 3
subjecting the solid to a heat treatment, thereby obtaining a silver-based electrical contact material... diamond is generated in situ of a material after being sintered
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3(a)~3(f)
AI summary
The present invention relates to a new method for preparing a silver-based electrical contact material, comprising following steps of: (a) providing a carbonaceous mesophase solution; (b) adding a silver source into the carbonaceous mesophase solution and stirring to obtain a compound; (c) removing a solvent from the compound to obtain a solid; (d) performing a heat treatment on the solid, and obtaining a silver-based electrical contact material. The silver source is silver powder prepared by means of a chemical method. By means of the method, a uniform carbonaceous coating on silver is implemented, the silver is uniformly distributed in a nanometer scale, and a diamond is generated in situ of a material after being sintered. The silver-based electrical contact material processed by means of this method shows an excellent mechanical wear resistance and electrical property.