Palladium-copper-silver-ruthenium alloy

Abstract

To provide an alloy and a wire, a strip or a probe needle which have a high electrical conductivity and, at the same time, a high degree of hardness, but which are simultaneously simple to produce and have as high an oxidation resistance as possible on the surface.SOLUTION: The invention relates to a palladium-copper-silver alloy with palladium as the main component, wherein the palladium-copper-silver alloy has a weight ratio of palladium to copper of at least 1.05 and at most 1.6 and has a weight ratio of palladium to silver of at least 3 and at most 6, and wherein the palladium-copper-silver alloy contains more than 1 wt % and up to a maximum of 6 wt % of ruthenium, rhodium or ruthenium, and rhodium and contains, as the remainder, palladium, copper and silver and at most 1 wt % of other metallic elements including impurities.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to palladium-copper-silver alloys (PdCuAg alloys), wires, strips or probe needles made from such palladium-copper-silver alloys, and the use of such palladium-copper-silver alloys for testing electrical contacts, for generating electrical contacts, or for manufacturing sliding contacts.

Background Art

[0002] During chip manufacturing, in order to test the operability of an integrated circuit (IC) in a state before separation, a probe needle is brought into contact with a wafer immediately after processing. After individual chips are formed, an array of probe needles is used to inspect the semiconductor wafer for functionality. The probe needles are fixed to a probe card adapted to the design of the wafer. In the test process, the wafer is pressed against the probe needles, and contact is established between the probe needles and the pads of the IC. In the case of aluminum pads, contact is established through a passivation layer. Thereafter, various parameters such as the contact state, electrical characteristic values at high current density, and electrical behavior during temperature change are tested.

[0003] Probe needles are thus used in the manufacture of power electronics and in the contact of chips and other electrical circuits to test the quality of electrical contacts (see, for example, U.S. Patent Application Publication No. 2014 / 0266278A1 and U.S. Patent Application Publication No. 2010 / 0194415A1).

[0004] Important parameters for excellent probe needles are high conductivity and high hardness. High conductivity is important because it is necessary to transmit a large current, and high hardness is important because it shortens the maintenance interval. Currently, so-called probe needles use metals or alloys with high conductivity and high thermal conductivity, as well as high hardness and high tensile strength. The electrical conductivity of pure copper (100% IACS = 58.1×10 6S / m is used as the standard. However, copper (Cu) and silver (Ag) are too ductile and are likely to deform during use, so they cannot be used for this purpose.

[0005] However, in addition to probe needles, materials with high electrical and thermal conductivity, as well as good mechanical properties such as high hardness and tensile strength, offer other advantages, particularly in applications such as wires for sliding contacts. In the case of sliding contacts, it is important that the contact resistance due to the surface is low, and that the material does not wear down too quickly, i.e., that it does not fray or erode too quickly.

[0006] In applications such as probe needles or sliding wires in power electronics, high conductivity is required, along with high mechanical strength and hardness. In this case, temperature resistance or heat resistance is also important.

[0007] Typical materials for probe needles include precipitation-hardening palladium-silver alloys that can contain 10% gold and 10% platinum, and are sold under product names such as Paliney® 7, Hera 6321, and Hera 648. These alloys have high hardness of 400-500 HV. However, their electrical conductivity is quite low, at 9-12% IACS. High conductivity is a very important factor for probe needles. For testing aluminum pads, probe needles made from materials such as tungsten, tungsten carbide, palladium-copper-silver alloys, and tungsten-rhenium are widely used. These are particularly hard, making aluminum pads more robust than gold pads and able to withstand testing with harder needles better than gold pads. These probe needles also do not have very high electrical conductivity. Alloys with high electrical conductivity, such as CuAg7, have lower hardness (approximately 320 HV) and lower heat resistance than palladium-silver alloys or palladium-copper-silver alloys.

[0008] As for palladium alloys (Pd alloys), for example, Deringer Ney's Paliney® H3C or Advanced Probing's NewTec® are known to be used for gold pads. Suitable palladium-copper-silver alloys are already known from U.S. Patent No. 1,913,423A and UK Patent Application Publication No. 354 216A. Palladium-copper-silver alloys can form structures with superlattices, which improves the conductivity and mechanical stability of the alloy. In this case, the atoms in the lattice are no longer statistically randomly distributed, but are arranged in a periodic structure called a superlattice. As a result, it becomes possible to achieve a hardness exceeding 350 HV1 (Vickers hardness test according to DIN EN ISO 6507-1:2018~-4:2018 with a test force of 9.81 N (1 kilopound)), an electrical conductivity exceeding 19.5% IACS, and a breaking strength up to 1500 MPa.

[0009] U.S. Patent Publication No. 2014 / 377129A1 and U.S. Patent No. 5,833,774A disclose hardened Ag-Pd-Cu alloys for electrical applications. Such palladium-copper-silver alloys have an electrical conductivity of about 9% to 12% IACS and a hardness of 400 to 500 HV1. Higher electrical conductivity would be desirable. U.S. Patent No. 10,385,424B2 discloses a palladium-copper-silver alloy containing up to 5 wt% additional rhenium. This palladium-copper-silver alloy is marketed under the product name Paliney® 25. In this way, the electrical conductivity can be significantly improved, achieving values ​​above 19.5% IACS. However, a disadvantage is that rhenium has a very high melting point (3180°C), and therefore must be alloyed with other metals in a complex manner. Rhenium has a high density (21 g / cm³). 3Rhenium's density also differs significantly from that of other elements (palladium (Pd), copper (Cu), silver (Ag)), which similarly complicates alloying with other elements. In addition, rhenium oxidizes at temperatures above 400°C, close to the operating temperature of the probe needle. Surface oxides can limit the function of the probe needle and sliding contacts. Furthermore, it is desirable to further increase the electrical conductivity and / or hardness of the alloy for use as a material for probe needles. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] U.S. Patent Application Publication No. 2014 / 0266278A1 [Patent Document 2] U.S. Patent Application Publication No. 2010 / 0194415A1 [Patent Document 3] U.S. Patent No. 1,913,423A [Patent Document 4] UK Patent Application Publication No. 354216A [Patent Document 5] U.S. Patent Application Publication No. 2014 / 377129A1 [Patent Document 6] U.S. Patent No. 5,833,774A [Patent Document 7] U.S. Patent No. 10,385,424B2 [Overview of the project] [Problems that the invention aims to solve]

[0011] Accordingly, the present invention addresses the challenge of overcoming the shortcomings of the prior art. In particular, there is a need to provide alloys and wires, strips, or probe needles that have high conductivity and high hardness, are easy to manufacture, and have the highest possible oxidation resistance on the surface. These molded products should be able to be produced in the most cost-effective way possible compared to comparable alloys. These alloys and products need to be usable as probe needles for testing electrical contacts.

[0012] Therefore, the object of the present invention is to find an alloy similar to known palladium-copper-silver alloys, but with higher conductivity, that combines the mechanical properties (hardness, yield strength, elasticity) of known palladium-copper-silver alloys. This type of palladium-copper-silver alloy offers a decisive technical advantage, particularly when used as a material for probe needles.

[0013] A further challenge addressed by the present invention is to provide a probe needle that satisfies the above-described characteristics. Another possible challenge is to develop a wire for sliding contacts that includes multiple wires made from such an alloy. [Means for solving the problem]

[0014] The problems addressed by the present invention are solved by a palladium-copper-silver alloy having palladium as the main component, wherein the palladium-copper-silver alloy has a weight ratio of palladium to copper of at least 1.05 and a maximum of 1.6, and a weight ratio of palladium to silver of at least 3 and a maximum of 6, and the palladium-copper-silver alloy contains more than 1% by weight and up to 6% by weight of ruthenium, rhodium, or ruthenium and rhodium, with the remainder being palladium, copper, and silver, and other metallic elements including up to 1% by weight of impurities.

[0015] A weight ratio of palladium to copper of at least 1.05 and at most 1.6 means that palladium is contained in the palladium - copper - silver alloy at a weight of at least 105% and at most 160% of the weight of copper contained in the palladium - copper - silver alloy.

[0016] Therefore, a weight ratio of palladium to silver of at least 3 and at most 6 means that palladium is contained in the palladium - copper - silver alloy at a weight of at least 3 times and at most 6 times the weight of silver contained in the palladium - copper - silver alloy.

[0017] A mixture of a plurality of elements is preferably understood to mean a mixture in which all of these elements are contained in the palladium - copper - silver alloy at least at 0.1% by weight.

[0018] The main component, in the context of this application, is mainly, that is, the element that is quantitatively the largest constituent (in this case palladium), that is, in the context of this application, it is understood that there is more palladium than copper or silver in the palladium - copper - silver alloy.

[0019] Impurities, in this specification, are understood to mean impurities caused by the presence of all relevant elements.

[0020] The palladium - copper - silver alloy is preferably suitable for the manufacture of probe needles and / or sliding contacts.

[0021] [[ID=X]]

[0022] ​The alloy is particularly preferably a mixture of ruthenium and rhodium, having 1.5% by weight of rhodium and ruthenium.

[0023] It can be provided that the total amount of impurities in the palladium-copper-silver alloy is at most 0.9% by weight, preferably at most 0.1% by weight.

[0024] This ensures that the physical properties of the palladium-copper-silver alloy are not affected by impurities, or are affected as little as possible.

[0025] Furthermore, it can be provided that the palladium-copper-silver alloy contains up to 1% by weight of rhenium, preferably less than 0.1% by weight of rhodium, and particularly preferably contains more than 1% by weight and up to 2% by weight of ruthenium and 0.1% to 1% by weight of rhenium, more preferably at least 1.1% by weight and up to 1.5% by weight of ruthenium and 0.2% to 0.8% by weight of rhenium, and particularly preferably 1.1% by weight of ruthenium and 0.4% by weight of rhenium.

[0026] The palladium-copper-silver alloy preferably contains more than 1% by weight and up to 6% by weight of ruthenium.

[0027] Surprisingly, this palladium-copper-silver alloy showed a 28% IACS (11 × 10) in the experiment. 6 It exhibited particularly high electrical conductivity (S / m) and simultaneously high hardness of 365HV1. This is thought to be due to ruthenium-rhenium precipitates formed at the grain boundaries of the palladium-copper-silver alloy.

[0028] Furthermore, the palladium-copper-silver alloy contains at least 45% and up to 55% by weight of palladium, at least 30% and up to 45% by weight of copper, and at least 8% and up to 15% by weight of silver. Preferably, the palladium-copper-silver alloy contains at least 50% and up to 53% by weight of palladium, at least 35% and up to 38% by weight of copper, and at least 9% and up to 12% by weight of silver, as well as at least 1.1% and up to 3% by weight of ruthenium and rhodium. Alternatively, the palladium-copper-silver alloy may contain ruthenium and rhodium, and is particularly preferably said to contain at least 51% and up to 52% by weight of palladium, at least 36% and up to 37% by weight of copper, and at least 10% and up to 11% by weight of silver, and contain at least 1.1% to up to 2% by weight of ruthenium, rhodium, or ruthenium and rhodium, and up to 0.5% by weight of other metallic elements, particularly 0.3% to 0.5% by weight of rhenium.

[0029] Palladium-copper-silver alloys of these compositions exhibit particularly high conductivity due to a superlattice formed within the alloy by a uniform order of palladium and copper atoms within the crystal lattice, rather than a random distribution of palladium and copper atoms. Remarkably, this effect appears to be enhanced by ruthenium or rhodium precipitates present in the palladium-copper-silver alloy. Simultaneously, high hardness is provided.

[0030] It is also possible to provide a palladium-copper-silver alloy that is manufactured by molten metallurgy, then hardened by rolling and tempering, and preferably has a hardness of at least 350 HV1.

[0031] In this way, the hardness of the palladium-copper-silver alloy can be improved.

[0032] The palladium-copper-silver alloy according to the present invention can also be characterized in that the palladium-copper-silver alloy has a hardness of at least 350 HV1.

[0033] The present invention further relates to a palladium-copper-silver alloy characterized by having an electrical conductivity of at least 19% IACS.

[0034] The palladium-copper-silver alloy according to the present invention may also be characterized by having a fracture strength of at least 1300 MPa.

[0035] Palladium-copper-silver alloys possessing these physical properties can be produced by adding ruthenium and rhodium according to the present invention, and are particularly suitable for the manufacture of probe needles.

[0036] The palladium-copper-silver alloy is ruthenium precipitate ,rhodium precipitate , or a mixture of ruthenium and rhodium precipitate Alternatively, the alloy may contain precipitates of a mixture of ruthenium and rhenium, preferably at least 90 volume percent of these precipitates being located at the grain boundaries of the palladium-copper-silver alloy, and particularly preferably at least 99 volume percent of these precipitates being located at the grain boundaries of the palladium-copper-silver alloy.

[0037] As a result, mechanical properties such as fracture strength and deformation resistance are improved. Consequently, the palladium-copper-silver alloy becomes more suitable for use as a probe needle.

[0038] Furthermore, it can be provided that the palladium-copper-silver alloy has a weight ratio of palladium to copper of at least 1.2 and a maximum of 1.55, preferably at least 1.3 and a maximum of 1.5, particularly preferably at least 1.35 and a maximum of 1.45, and most preferably 1.41.

[0039] These weight ratios provide a palladium-copper-silver alloy with particularly high conductivity.

[0040] It can also be provided that the palladium-copper-silver alloy has a weight ratio of palladium to silver of at least 3.5 and a maximum of 5.5, preferably at least 4 and a maximum of 5.5, particularly preferably at least 4.6 and a maximum of 5.2, and even more preferably at least 4.9.

[0041] These weight ratios also provide a palladium-copper-silver alloy with particularly high conductivity.

[0042] The palladium-copper-silver alloy can also preferably be provided to contain at least 1.1% by weight of ruthenium, rhodium, or ruthenium and rhodium.

[0043] This improves the conductivity and mechanical properties of the palladium-copper-silver alloy.

[0044] Furthermore, it can be provided that the palladium-copper-silver alloy contains up to 5% by weight of ruthenium, rhodium, or ruthenium and rhodium, preferably up to 4% by weight of ruthenium, rhodium, or ruthenium and rhodium, particularly preferably up to 3% by weight of ruthenium, rhodium, or ruthenium and rhodium, and more preferably up to 2% by weight of ruthenium, rhodium, or tungsten, ruthenium and rhodium.

[0045] These measures also help to improve the conductivity of the palladium-copper-silver alloy.

[0046] It can also be provided that the palladium-copper-silver alloy contains more than 1% by weight and up to 6% by weight of rhodium or ruthenium, preferably more than 1% by weight and up to 3% by weight of rhodium or ruthenium, particularly preferably at least 1.1% by weight and up to 2% by weight of rhodium or ruthenium, and more preferably 1.5% by weight of rhodium or 1.5% by weight of ruthenium.

[0047] These palladium-copper-silver alloys are characterized by particularly high mechanical hardness (HV1).

[0048] Alternatively, the palladium-copper-silver alloy may contain more than 1% by weight and up to 6% by weight of ruthenium and rhenium, preferably at least 1.1% by weight and up to 3% by weight of ruthenium and rhenium, particularly preferably at least 1.1% by weight and up to 2% by weight of ruthenium and rhenium, and more preferably 1.1% by weight of ruthenium and 0.4% by weight of rhenium.

[0049] This can provide that the palladium-copper-silver alloy contains more ruthenium than rhenium.

[0050] This type of palladium-copper-silver alloy is characterized by particularly high conductivity.

[0051] The problems addressed by the present invention are also solved by a wire, strip, or probe needle made of or having a palladium-copper-silver alloy according to the present invention, preferably by a wire, strip, or probe needle in which at least one internal core is made of the palladium-copper-silver alloy.

[0052] Wires, strips, and probe needles made from such palladium-copper-silver alloys are particularly suitable for electrical contact measurements due to their high hardness, elasticity, and conductivity.

[0053] The problems addressed by the present invention can also be solved by using the palladium-copper-silver alloy according to the present invention, or by using the wire or strip according to the present invention, or by using the probe needle according to the present invention, for testing electrical contacts, or for generating electrical contacts, or for generating sliding contacts.

[0054] The palladium-copper-silver alloy and the wires, strips, and probe needles produced therefrom are particularly well suited for these applications.

[0055] This invention is based on the remarkable discovery that the palladium-copper-silver alloy according to the present invention possesses high conductivity, high hardness and fracture strength, is easy to manufacture, and / or is particularly hard. (Density of ruthenium: 12.4 g / cm³) 3 ) and the density of rhodium (12 g / cm³) 3 The melting points of these metals (ruthenium at 2334°C and rhodium at 1964°C) are quite close to those of palladium, copper, and silver, respectively, and therefore they can be alloyed more readily with these metals than metals with significantly different densities and melting points, such as rhenium. In addition, the surface of the palladium-copper-silver alloy is not easily oxidized even at high temperatures of around 400°C. Ruthenium and rhodium only form oxides from about 700°C. Wires, strips, and probe needles manufactured from the alloy according to the present invention have correspondingly advantageous properties. When measuring ruthenium or palladium-copper-silver alloys containing ruthenium and rhenium, even IACS electrical conductivity of 27% and 28% can be achieved. With palladium-copper-silver alloys containing rhodium, surprisingly high hardness was obtained.

[0056] In this invention, an electrical conductivity of 23% IACS or higher is possible. 100% IACS is 58 m / (Ω·mm). 2 This corresponds to ).

[0057] The use of ruthenium or rhodium as alloying elements in palladium-copper-silver alloys is surprising compared to the use of rhenium, due to the different chemical properties of these elements. Compared to rhenium, rhodium and ruthenium both belong to different main groups and periods of the periodic table, which, as a first approximation, suggests very different properties and different alloying behaviors. Rhodium and ruthenium are platinum group metals, while rhenium belongs to the same group as manganese, so similarity in properties cannot be expected. Rhenium has a hexagonal crystal structure, while rhodium has a face-centered cubic structure.

[0058] Ruthenium has a lower solubility in silver than rhenium (1.44 × 10⁻¹⁰ for rhenium). -3 In comparison, ruthenium is 2.65 × 10⁻⁶ -4 This should have a positive effect on the conductivity of the palladium-copper-silver alloy according to the present invention. In addition, electron microscopy studies revealed ruthenium precipitates at the grain boundaries of palladium-copper-silver alloys containing 1.1% to 1.5% by weight of ruthenium. These may lead to an increase in the hardness of the palladium-copper-silver alloy through precipitation hardening.

[0059] The palladium-copper-silver alloy according to the present invention is characterized by high hardness, good elasticity, and good conductivity. Therefore, the palladium-copper-silver alloy according to the present invention is ideal for use as a material for manufacturing probe needles.

[0060] For weight ratios of palladium to copper (1.05 to 1.6), appropriate heat treatment can establish an ordered superstructure (also called a superlattice) in the crystal lattice. The regular arrangement of palladium and copper atoms improves both the hardness and conductivity of the palladium-copper-silver alloy. Alloying silver with a palladium-to-silver ratio of 3 to 6 allows for further improvement in strength through precipitation hardening. Alloying ruthenium, rhodium, or ruthenium and rhodium in the range of 1% to 6% by weight surprisingly contributes to the formation of fine crystal grains, which positively impacts the hardness and formability of the palladium-copper-silver alloy. In addition, ruthenium, rhodium, or mixtures thereof, preferably located at grain boundaries, prevent grain growth and creep at operating temperatures. As a result, the durability of probe needles manufactured from this alloy is improved. Rhenium up to 1% by weight can be alloyed with ruthenium. The electrical conductivity achieved with 27% to 30% IACS and hardness exceeding 400 HV make it particularly suitable for use as a probe needle. Thus, the physical properties of the palladium-copper-silver alloy according to the present invention, with respect to conductivity and hardness, are superior to those of Paliney® 25. [Brief explanation of the drawing]

[0061] [Figure 1] Figure 1 shows the microstructure image of the Hera-6321 alloy that was examined. [Figure 2] Figure 2 shows the microstructure image of the PdCuAgRu alloy that was examined. [Figure 3] Figure 3 shows the microstructure image of the PdCuAgRuRe alloy that was examined. [Figure 4] Figure 4 shows the microstructure image of the PdCuAgRh alloy that was examined. [Modes for carrying out the invention]

[0062] Exemplary embodiments of the present invention will be described below, however, without limiting the invention.

[0063] The palladium-copper-silver alloys described below were first produced by manufacturing the master alloys through induction melting. Palladium-ruthenium, palladium-rhenium, and palladium-rhodium master alloys were produced. Since the melting points and densities of the elements palladium, ruthenium, and rhodium are not significantly different from each other, the production of these master alloys is simple, cost-effective, and requires little effort.

[0064] Next, these base alloys were alloyed with copper and silver by arc melting. The resulting molten body was then shaped and hardened by heat treatment and rolling. For this purpose, the body was tempered at 900°C for 120 minutes and rapidly cooled. This body was then rolled to 0.4 mm at room temperature, undergoing several intermediate annealing cycles at 900°C for 120 minutes each, and subsequently held at 380°C for 1.5 hours, resulting in a hardened state.

[0065] Subsequently, the electrical conductivity was measured using the four-point measurement method. The four-point measurement method, also known as the four-terminal measurement method, four-wire measurement method, or Kelvin measurement method, is a method for measuring sheet resistance, i.e., the electrical resistance of a surface or thin layer. In this method, four measurement points are placed in a row on the surface of the film, a known current is passed through two outer measurement points, and the potential difference, i.e., the voltage between these two inner measurement points, is measured using two inner measurement points. Because this method is based on the principle of four-wire measurement, it is largely independent of the contact resistance between the measurement points and the surface (Thomson bridge principle). Adjacent measurement points are spaced equally apart. The sheet resistance R is calculated from the measured voltage U and current I using the following formula.

number

[0066] To calculate the resistivity ρ of a layer material from the sheet resistance R, multiply the sheet resistance R by the film thickness d (layer thickness). ρ = dR

[0067] Electrical conductivity is derived from the reciprocal of resistivity.

[0068] Hardness was investigated (Vickers hardness test according to DIN EN ISO 6507-1:2018~-4:2018 with a test force of HV1 - 9.81 N (1 kilopound)), strength was investigated by tensile testing, and microstructure was examined by metallographic sections.

[0069] The following palladium-copper-silver alloys were manufactured and examined. 1. 51.5Pd, 36.5Cu, 10.5Ag, 1.5Ru (PdCuAgRu) 2. 51.5Pd, 36.5Cu, 10.5Ag, 1.1Ru, 0.4Re(PdCuAgRuRe) 3. 51.5Pd, 36.5Cu, 10.5Ag, 1.5Rh(PdCuAgRh)

[0070] The data always indicates the weight percentage (W%) of the alloy. In addition, these alloys contain conventional impurities at concentrations of less than 0.1 Wt%.

[0071] For comparison, a palladium-copper-silver alloy with the composition Pd 39 wt%, Cu 31 wt%, Ag 29 wt%, Zn 0.9 wt%, and B 0.1 wt%, trade name: Hera 6321, was also examined.

[0072] [Table 1]

[0073] Measurements of PdCuAgRu alloy, PdCuAgRuRe alloy, and PdCuAgRh alloy were performed on metal plates with a thickness of 0.4 mm. Hera-6321 alloy was measured on a metal plate with a thickness of 54 μm.

[0074] The microstructure images of the alloys examined are described below with reference to the four figures. Figure 1: Microstructure image of the Hera-6321 alloy examined. Figure 2: Microstructure images of the PdCuAgRu alloys examined. Figure 3: Microstructure images of the PdCuAgRuRe alloys examined. Figure 4: Microstructure images of the PdCuAgRh alloys examined.

[0075] All microstructure images (Figures 1-4) show alloys in a precipitation-hardened state. These images were obtained by photographing cross-sections of the alloys using an optical microscope (reflection-type optical microscope, bright-field). To make the precipitates more visible, the surface was smoothed by etching the microstructure. In Figures 2-4, the precipitates are shown within the alloy as dark contrasts against a bright matrix of the noble metal alloy. In Figure 1, silver precipitates in the alloy can be seen as bright contrasts against a dark matrix.

[0076] The precipitates in PdCuAgRuRe alloys are smaller and more dispersed than those in PdCuAgRu alloys. PdCuAgRh alloys have the smallest precipitates. However, precipitate size is not an indicator of alloy quality.

[0077] Measurement results showed that the palladium-copper-silver alloys according to the present invention, containing more than 1% by weight of ruthenium, rhodium, or both ruthenium and rhodium, exhibited higher electrical conductivity (2.3 to 3 times higher) compared to Hera 6321. At the same time, the hardness of the palladium-copper-silver alloys containing ruthenium or rhodium was only slightly (about 10%) lower than that of Hera 6321. The palladium-copper-silver alloys containing ruthenium even had somewhat higher electrical conductivity than the palladium-copper-silver alloys described in U.S. Patent No. 10,385,424B1. The palladium-copper-silver alloys containing rhodium were characterized by even higher hardness.

[0078] The features of the present invention disclosed in the above description, claims, figures, and exemplary embodiments may be essential individually or in any combination to realize the invention in its various embodiments.

Claims

1. A palladium-copper-silver alloy with palladium as the main component, The aforementioned palladium-copper-silver alloy is Palladium in an amount of 51% to 52% by mass, Copper in an amount of 36% to 37% by mass, Silver in an amount of 10% to 11% by mass, A palladium-copper-silver alloy characterized by containing 1.1% by mass or more and 1.5% by mass or less of ruthenium, rhodium, or ruthenium and rhodium, and less than 0.1% by mass of impurities, having a hardness of 350 HV1 or higher and an electrical conductivity of 19% IACS or higher.

2. The palladium-copper-silver alloy according to claim 1, characterized in that the palladium-copper-silver alloy contains 0.4% by mass or less of rhenium.

3. The aforementioned palladium-copper-silver alloy is The palladium-copper-silver alloy according to claim 1 or 2, characterized by containing 0.3% to 0.4% by mass of rhenium.

4. The aforementioned palladium-copper-silver alloy is PdCuAgRu alloy containing Pd, Cu, Ag, and Ru, PdCuAgRuRe alloy containing Pd, Cu, Ag, Ru, and Re, or A PdCuAgRh alloy containing Pd, Cu, Ag, and Rh, A palladium-copper-silver alloy according to any one of claims 1 to 3, characterized by having a yield strength of 1050 MPa or more.

5. The palladium-copper-silver alloy according to any one of claims 1 to 4, characterized in that the palladium-copper-silver alloy contains ruthenium precipitates, rhodium precipitates, or ruthenium and rhodium precipitates.

6. The palladium-copper-silver alloy according to any one of claims 1 to 4, characterized in that the palladium-copper-silver alloy contains precipitates of ruthenium and rhenium.

7. The palladium-copper-silver alloy according to claim 5 or 6, characterized in that 90 volume percent or more of the precipitate is located at the grain boundaries of the palladium-copper-silver alloy.

8. The palladium-copper-silver alloy according to claim 5 or 6, characterized in that 99 volume percent or more of the precipitates are located at the grain boundaries of the palladium-copper-silver alloy.

9. The aforementioned palladium-copper-silver alloy is The mass ratio of palladium to copper is 1.35 or more and 1.45 or less. The palladium-copper-silver alloy according to any one of claims 1 to 8, characterized in that the mass ratio of palladium to silver is 4.6 or more and 5.2 or less.

10. The palladium-copper-silver alloy according to claim 9, characterized in that the mass ratio of palladium to copper is 1.

41.

11. The palladium-copper-silver alloy according to claim 9 or 10, characterized in that the mass ratio of palladium to silver is 4.

9.

12. The palladium-copper-silver alloy according to claim 1, claim 2, or any one of claims 4 to 11, characterized in that the palladium-copper-silver alloy contains 1.5% by mass of rhodium or 1.5% by mass of ruthenium.

13. The palladium-copper-silver alloy according to claim 1, claim 2, or any one of claims 4 to 11, characterized in that the palladium-copper-silver alloy contains less than 0.1% by mass of rhodium.

14. The palladium-copper-silver alloy according to any one of claims 1, 2, 4 to 11, and 13, characterized in that the palladium-copper-silver alloy contains 1.1% by mass of ruthenium and 0.4% by mass of rhenium.

15. The palladium-copper-silver alloy according to claim 1, claim 2, or any one of claims 4 to 11, characterized in that the palladium-copper-silver alloy contains 0.4% by mass or less of rhenium.

16. The palladium-copper-silver alloy according to claim 1, claim 2, or any one of claims 4 to 11, characterized in that the palladium-copper-silver alloy contains 1.1% by mass of ruthenium and 0.4% by mass of rhenium.

17. A wire characterized by having a palladium-copper-silver alloy as described in any one of claims 1 to 16.

18. The wire according to claim 17, characterized in that at least one internal core of the wire is made of the palladium-copper-silver alloy.

19. A strip characterized by having a palladium-copper-silver alloy as described in any one of claims 1 to 16.

20. The strip according to claim 19, characterized in that at least one internal core of the strip is made of the palladium-copper-silver alloy.

21. A probe needle characterized by having a palladium-copper-silver alloy as described in any one of claims 1 to 16.

22. The probe needle according to claim 21, characterized in that at least one internal core of the probe needle is made of the palladium-copper-silver alloy.

23. Use of the palladium-copper-silver alloy according to any one of claims 1 to 16 for testing electrical contacts.

24. Use of the palladium-copper-silver alloy according to any one of claims 1 to 16 for generating electrical contacts.

25. Use of the palladium-copper-silver alloy according to any one of claims 1 to 16 for generating a sliding contact.

26. A method for producing a palladium-copper-silver alloy according to any one of claims 1 to 16, A method for producing a palladium-copper-silver alloy, characterized by manufacturing the palladium-copper-silver alloy by molten metallurgy, and then hardening it by rolling and tempering.

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