Background technology
Fine silver has the highest specific conductivity, and contact resistance is stable, is widely used in high conductivity, the contact material of middle low current range.But the mechanical property of fine silver is relatively poor, has natural ageing and softening, defectives such as transfer and melting welding very easily take place under more high-power loading condiction.Alloyage process can significantly can improve hardness, intensity and the wear resistance of silver-colored material.For a long time, in contact material, formed based on the solution strengthening type series alloy of Ag-Cu and the dispersion strengthening type series alloy of Ag-Ni.Wherein be most widely used with yellow gold.But yellow gold is under industrial atmosphere, and especially in high temperature, high humidity and sulfide hydrogen atmosphere, the surface generates nonconducting sulfide film and oxide film easily, causes the contact resistance instability, and contact reliability reduces.Simultaneously, because copper content is lower, the softening temperature of alloy low (~260 ℃), high-speed slide friction between reverser and the brush plate in the machine operation process, the high temperature that joule heating that electric current produces under the action of a magnetic field and electric arc three act on generation easily makes the commutator segment local softening, the commutator material frictional coefficient increases considerably, and has quickened the early failure of commutator segment.
Ni is the grain-refining agent of Ag alloy, can the stable prod size, significantly improve the wear resistance and the erosion resistance of body material; And in alloy, add small amount of N i, can further improve the anti electric arc corrosion performance of material.Even but since high temperature (~1000 ℃) down Ni and Ag matrix dissolve each other hardly, Ni is poly-very easily partially in the silver alloys matrix, and the homogeneity of structure of founding silver matrix is had a significant impact.Therefore also there is certain difficulty in the AgCu alloy of high Ni content aspect melting.
Existing technical literature retrieval is shown that document [China Patent CN 101029362A] has improved AgCu by adding Sn and a spot of Ce element
6Hardness of alloy and wear resistance.In further retrieving, find the relevant report of the softening temperature aspect of raising Ag-Cu alloy as yet.
Summary of the invention
Technical problem to be solved by this invention is for the softening temperature that overcomes existing AgCu alloy material is lower, the contact resistance instability, and contact reliability is low, and softening temperature is low, the low defective of hardness and wear resistance under the high temperature, and a kind of Pd-Ag substrate alloy material is provided.Pd-Ag substrate alloy material of the present invention can be used as gently, moderate duty micromotor sliding contact material, and the softening temperature height, and hardness is good under the high temperature, and wear resistance is good.
The inventor finds: rare earth element Gd has good alloying effect in alloy, can improve the original microstructure of alloy, significantly improves the hardness and the intensity of alloy substrate; Rare earth and alloy can form high melting compound simultaneously, improve the alloy softening temperature, improve hardness and intensity under the alloy high-temp.
Therefore the present invention relates to a kind of Pd-Ag substrate alloy material, it comprises following ingredients: 0.05%~0.5% Ni, 0.1%~0.8% Gd, and 98.7%~99.85% AgCu
4Alloy (Ag is 96wt.% in the alloy, and Cu is 4wt.%), above per-cent is mass percent.
Preferable, described Pd-Ag substrate alloy material comprises following ingredients: 0.05%~0.15% Ni, 0.54%~0.8% Gd, and 99.05%~99.41% AgCu
4Alloy, above per-cent is mass percent.
Pd-Ag substrate alloy material of the present invention can be by the ordinary method preparation of this area alloy material, and preferred following method: with Ni, Gd, Ag and Cu is raw material, carries out following operation according to above-mentioned mass percent:
1. vacuum argon shield melting 2. the thermal treatment of 700 ℃/3h of ingot casting homogenizing 3. the 4. cold rolling cogging of surface treatment 5. roll in 650 ℃ of-680 ℃/2.5-3h (vacuum) annealing 6. 7. 700 ℃/1h (nitrogen+hydrogen shield annealing) 8. finish rolling 9. obtain Pd-Ag substrate alloy material.
Preferable, described Pd-Ag substrate alloy material also can be by AgCu
4Alloy (Ag is 96wt.% in the alloy, and Cu is 4wt.%), Ni and Gd carry out above-mentioned operation as raw material and make.
Among the preparation method of the present invention, raw material Ni, Gd, Ag and Cu can mix with the form of pure metal respectively, also can be alloy and other metal mixed that two or more metals wherein form, carry out subsequent handling then, no matter according to above which kind of mode, as long as the mass percent of each composition in the alloy material that the mass percent that guarantees each metal prepares for the present invention.
Among the present invention, what the purity of described Ag was preferable is 〉=99.99%, and what the purity of Cu was preferable is 〉=99.99%, and what the purity of Ni was preferable is 〉=99.99%, and what the purity of Gd was preferable is 〉=99.96%.Above per-cent is mass percent.
The invention still further relates to of the application of above-mentioned Pd-Ag substrate alloy material as sliding contact material.The micromotor sliding contact material that described sliding contact material is preferable for light or moderate duty.
Except that specified otherwise, the raw material of the present invention design and reagent is all commercially available gets.
Positive progressive effect of the present invention is:
(1) Pd-Ag substrate alloy material of the present invention is the low high-intensity silver-copper rare earth alloy of Ni content, and it can be used as gently, moderate duty micromotor sliding contact material.
(2) Pd-Ag substrate alloy material of the present invention has improved Ag-Cu hardness of alloy and softening temperature, thereby has improved anti-electrical arc erosion performance, resistance fusion welding energy and the anti-metal transfer performance of material, has improved the electrical contact reliability of Ag-Cu alloy.Therefore this material can solve AgCu
4Problems such as the contact resistance instability of alloy under comparatively high temps, contact reliability reduce, and hardness and wear resistance are low.
Embodiment
Further specify the present invention with embodiment below, but the present invention is not limited.
The performance data of the prescription of embodiment 1~4 and the Pd-Ag substrate alloy material that makes and AgCu
4The performance data of alloy is as shown in table 1.The material purity that uses among each embodiment (mass percent) is: Ag 〉=99.99%, Cu 〉=99.99%, Ni 〉=99.99%, Gd 〉=99.96%.
The foreign matter content that allows in the Pd-Ag substrate alloy material that each embodiment makes (mass percent): Fe≤0.002%, Pd≤0.002%, Sb≤0.002%, Bi≤0.002%.
The performance data of table 1 Pd-Ag substrate alloy material of the present invention and AgCu4 alloy
The preparation method of embodiment 1~4 is as described below:
(%) by mass percentage: with AgCu
4Alloy, Ni and Gd are raw material, carry out following operation according to the prescription among each embodiment: 1. vacuum argon shield melting 2. the thermal treatment of 700 ℃/3h of ingot casting homogenizing 3. the 4. cold rolling cogging of surface treatment 5. roll in 650 ℃ of-680 ℃/2.5-3h (vacuum) annealing 6. 7. 700 ℃/1h (nitrogen+hydrogen shield annealing) 8. finish rolling 9. obtain Pd-Ag substrate alloy material.