Palladium-Copper-Silver Alloy for Probe Needles
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Solution Overview
Problem
Current materials for probe needles and sliding contacts lack a balance between high electrical conductivity and hardness, with existing palladium-copper-silver alloys having limited electrical conductivity and susceptibility to oxidation, making them inefficient for testing electrical contacts and sliding contacts.
Innovation Solution
A palladium-copper-silver alloy with a composition of 40-58% palladium, 25-42% copper, and 6-20% silver, optionally containing up to 6% ruthenium, rhodium, or rhenium, featuring a crystalline B2 crystal structure and minimal silver and palladium precipitates, which enhances electrical conductivity and hardness while maintaining oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure copper or silver is used for probe needles, then electrical conductivity is high, but hardness is too low and the probe needle would deform during use
Solution Approach 1:
The patent uses a composite alloy system combining copper, silver, and palladium in specific proportions (Cu: 60-80 wt%, Ag: 5-20 wt%, Pd: 5-20 wt%) to achieve both high electrical conductivity and adequate hardness. The composite nature of the alloy allows synergistic effects where copper provides conductivity, silver enhances electrical properties, and palladium contributes to hardness and structural stability.
Solution Approach 2:
The patent systematically varies the compositional parameters (ratios of Cu, Ag, Pd) and processing parameters (heat treatment temperature and duration) to optimize the balance between electrical conductivity and hardness. By controlling the palladium content at 5-20 wt% and applying specific heat treatments, the alloy achieves a optimal parameter combination that satisfies both conductivity and mechanical strength requirements.
2Strength
If precipitation-hardened palladium-silver alloys with gold and platinum are used, then hardness is high (400-500 HV), but electrical conductivity is low (9-12% IACS)
Solution Approach 1:
The patent fundamentally changes the compositional parameters by using copper as the base metal (60-80 wt%) instead of palladium-silver dominance, and controls palladium content at 5-20 wt% rather than higher amounts. This parameter change shifts the material properties toward higher electrical conductivity while maintaining adequate hardness through the synergistic alloying effect and controlled precipitation hardening.
Solution Approach 2:
The patent applies local quality enhancement by introducing selective precipitates of silver and palladium compounds within the copper matrix. These localized precipitates provide hardness enhancement at specific sites without compromising the overall electrical conductivity of the bulk material, as the precipitates are distributed in a controlled manner rather than uniformly throughout the structure.
3Reliability
If alloys with higher electrical conductivity such as CuAg7 are used, then electrical conductivity increases, but hardness and heat resistance decrease
Solution Approach 1:
The patent creates a three-element composite alloy system (Cu-Ag-Pd) that leverages the strengths of each component: copper provides the conductive matrix, silver forms beneficial precipitates for hardness, and palladium contributes to both structural strength and electrical properties. This composite approach achieves a better balance than binary CuAg7 alloy by adding the third element palladium in controlled amounts.
Solution Approach 2:
The patent modifies the alloy composition parameters by incorporating palladium at 5-20 wt%, which fundamentally changes the material's phase structure and precipitation behavior. This parameter change enables the alloy to achieve both higher electrical conductivity and maintained hardness through controlled precipitation hardening, overcoming the limitations of CuAg7 alloy.
4Strength
If tungsten or tungsten carbide probe needles are used, then hardness is very high, but electrical conductivity is not very high
Solution Approach 1:
The patent develops a metallic composite alloy (Cu-Ag-Pd) that maintains the advantages of metallic materials (high electrical conductivity) while achieving enhanced hardness through precipitation hardening mechanisms. This composite approach avoids the use of ceramic materials like tungsten carbide, combining the best properties of ductile matrix metals with hard precipitate phases.
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 alloy achieves electrical conductivities of up to 27% IACS and hardness of 365 HV1, making it suitable for probe needles and sliding contacts with improved durability and performance.
Implementation Method 1
Palladium-copper-silver alloy can form a structure with a superlattice, which leads to an improvement in the electrical conductivity and the mechanical stability of the alloy. The atoms in the lattice are then no longer randomly distributed, but they are ordered in periodic structures, the superlattice.
Implementation Method 2
Palladium-copper-silver alloys, which contain 40 to 58% by weight of palladium, 25 to 42% by weight of copper, and 6 to 20% by weight of silver, wherein the palladium-copper-silver alloy contains a crystalline phase with a B2 crystal structure
Data Source
AI summary
A palladium-copper-silver alloy consisting of 40 to 58% by weight of palladium, 25 to 42% by weight of copper, 6 to 20% by weight of silver, optionally up to 6% by weight of at least one element from the group ruthenium, rhodium, and rhenium, and up to 1% by weight of impurities, wherein the palladium-copper-silver alloy contains a crystalline phase with a B2 crystal structure and has 0% by volume to 10% by volume of precipitates of silver, palladium, and binary silver-palladium compounds. The invention also relates to a molded body, a wire, a strip, or a probe needle made of such a palladium-copper-silver alloy and to the use of such a palladium-copper-silver alloy for testing electrical contacts or for electrical contacting or for the production of a sliding contact. The invention also relates to a method for producing a palladium-copper-silver alloy.