Silver-Carbon Nano Tube Electrical Contacts
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Solution Overview
Problem
Existing electrical contact materials, such as Ag-CdO alloys, face issues with high production costs, environmental pollution due to toxic cadmium oxide, and reduced abrasion resistance due to oxidation, while alternatives like Ag-CNTs are costly and complex to prepare.
Innovation Solution
A metal-metal oxide based electrical contact material using a composite of metals like Ag, Ni, and Cu with carbon nano tubes (CNTs) coated with Ag nanoparticles or plated with Ag, or Ag nanowires, which are sintered using spark plasma sintering to reduce costs and enhance mechanical and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ag-CdO alloy is used as electrical contact material, then welding resistance and attrition resistance are improved, but oxidation causes coarsening of oxide particles and formation of oxidation sparse layer, reducing hardness and abrasion resistance
Solution Approach 1:
The patent changes the chemical composition parameters by replacing toxic CdO with non-toxic alternatives like Bi2O3, ZnO, or B2O3, while maintaining the alloy structure. This substitution prevents oxidation-related degradation while preserving welding resistance, thereby resolving the contradiction between reliability and strength.
Solution Approach 2:
The patent creates composite materials by combining Ag with alternative metal oxides (Bi2O3, ZnO, B2O3) and sometimes with hardening agents like SiC or Al2O3. These composites provide both oxidation resistance and maintained hardness, solving the contradiction between welding resistance and hardness retention.
2Reliability
If Ag is used as base material of electrical contacts, then electrical conductivity and thermal conductivity are improved, but abrasion resistance and impact resistance are weak, and cost increases
Solution Approach 1:
The patent develops composite materials combining Ag with alternative metal oxides and hardening agents. The Ag matrix provides excellent electrical conductivity while the embedded oxide particles and hardening agents provide abrasion and impact resistance, resolving the contradiction between electrical performance and mechanical strength.
Solution Approach 2:
The patent applies local quality enhancement by distributing hardening agents and metal oxide particles throughout the Ag matrix. This creates regions of enhanced hardness and wear resistance while maintaining the overall electrical conductivity of the Ag-based material.
3Reliability
If Ag-CdO alloy is used, then stable thermal and electrical properties are achieved, but CdO has strong toxicity and causes environmental pollution
Solution Approach 1:
The patent replaces toxic CdO with non-toxic, environmentally friendly alternatives such as Bi2O3, ZnO, and B2O3. These substitute materials provide similar thermal and electrical stability without the harmful environmental effects, eliminating toxicity while maintaining reliability.
Solution Approach 2:
The patent changes the chemical composition by substituting toxic elements with non-toxic alternatives that have comparable or superior thermal and electrical properties. This parameter change eliminates environmental harm while preserving the stable thermal and electrical characteristics required for reliable electrical contact performance.
4Reliability
If Ag-CNTs are used to improve abrasion resistance and electrical property, then electrical characteristics are improved, but preparation cost is high and preparation processes are complicated
Solution Approach 1:
The patent replaces expensive and difficult-to-process CNTs with more affordable and easier-to-manufacture alternative metal oxides and conventional hardening agents. These substitutes provide comparable electrical and mechanical properties through simpler, more cost-effective manufacturing processes.
Solution Approach 2:
The patent changes the material composition parameters by substituting CNTs with alternative metal oxides and hardening agents that can be more easily incorporated into the Ag matrix. This simplifies the preparation process while maintaining or improving electrical characteristics and abrasion resistance.
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 solution significantly reduces the use of high-priced metals, improves abrasion resistance and electrical conductivity, and simplifies the preparation process, resulting in a cost-effective and environmentally friendly electrical contact material with enhanced hardness and conductivity.
Implementation Method 1
the powder mixture is sintered to prepare a sintered body
Data Source
Figure 1A~1B
Figure 1C
Figure 2(a)~2(c)
AI summary
Disclosed are electrical contact materials and a method for preparing the same. The electrical contact material includes (i) one or more kinds of metals selected from the group consisting of silver (Ag), copper (Cu) and gold (Au), and an alloy of nickel (Ni); and (ii) carbon nano tubes (CNTs) coated with Ag nanoparticles, Ag plated CNTs, or Ag nanowires, or (i) one or more kinds of metals selected from the group consisting of Ag, Cu, Ni and Au; (ii) a metal oxide that is cadmium oxide, indium oxide, tin oxide, zinc oxide or mixture thereof; and (iii) CNTs coated with Ag nanoparticles, Ag plated CNTs, or Ag nanowires. Accordingly, it is possible to reduce the content of high-priced Ag and to obtain excellent electrical and mechanical properties.