{"title":"Wear resistance of nickel and nickel phosphorus alloy electrodeposits","authors":"C. A. Holden, R. Opila, H. H. Law, G. R. Crane","doi":"10.1109/33.19014","DOIUrl":"https://doi.org/10.1109/33.19014","url":null,"abstract":"The wear resistance of gray Ni/Cl and Ni/P deposits was evaluated using a crossed-wire test method that stimulates the wear that develops on plug-in type printed wiring boards. All wear samples were lubricated with 2-wt.% five- or six-ring polyphenylether fluid. Some samples plated with a thin layer of cobalt-hardened gold were also examined. Wear test results showed that: (1) gray Ni/P deposits plated from a neutral ammoniacal bath are more wear-resistant for up to 100 wear cycles than nickel deposits plated from an acid chloride bath; (2) hard-gold-flashed Ni/P deposits are more wear-resistant for up to 5000 wear cycles at a 200-g load than hard-gold-flashed nickel deposits plated from an acid chloride bath. A minimum of 5 mu in. hard gold provides this wear protection.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"518 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116242547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The development of silver-based cadmium-free contact materials","authors":"P. Wingert, C. Leung","doi":"10.1109/33.19007","DOIUrl":"https://doi.org/10.1109/33.19007","url":null,"abstract":"A procedure is described that allows contact material compositions to be developed by a systematic progression through several levels of component evaluations and selections based on electrical test results. The testing and selection methodology is designed to develop the best contact material composition while also evaluating how changes in composition can be expected to alter the contact performance of the family of materials being evaluated. Specifically, the procedure is described for the development of cadmium-free contact materials. The cadmium-free material developed is shown to exhibit superior weld resistance and lower erosion weight loss relative to a good high-density P/M silver-cadmium oxide material.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"169 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123260431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cracking mechanisms in Ag-SnO2 contact materials and their role in the erosion process","authors":"S. Kang, C. Brecher","doi":"10.1109/33.19009","DOIUrl":"https://doi.org/10.1109/33.19009","url":null,"abstract":"The authors present the results of an investigation conducted into the factors governing the erosion of Ag-SnO/sub 2/ electric contact materials by repeated electric arcing and the manner in which these factors are altered by chemical effects. Two features found to have major influences were the inhomogeneous interfaces between the Ag matrix and the SnO/sub 2/ granules, and the wetting characteristics of the surface. The Ag/SnO/sub 2/ interfaces, which serve as paths for crack propagation, appear to have dominant influence during the earlier stages of erosion, while the extent of surface wetting by molten silver, which was found capable of altering the stress intensity at the crack tip, predominates in the later stages. The effect of dopant additives in altering the surface activity was also examined.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123328466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electrical contact bounce in medium duty contacts","authors":"J. McBride","doi":"10.1109/33.19016","DOIUrl":"https://doi.org/10.1109/33.19016","url":null,"abstract":"The basic phenomena of electrical contact bounce with the passage of current, in the medium duty range (1 to 30 A AC and DC), are investigated. Experimental results presented show that by considering individual impacts, an understanding of how current affects contact bounce is achieved. An automated test system is used to evaluate contact bounce. The surface degradation is evaluated by endurance testing, allowing the development of empirical relations between mechanical and electrical bounce. With this understanding it is shown how arc energy dissipation can be reduced by the designed reduction of impact kinetic energy, leading to prolonged contact life.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129785929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Kuhlmann-wilsdorf, D. Makel, N. Sondergaard, D. Maribo
{"title":"On the two modes of operation of monolithic Ag-C brushes","authors":"D. Kuhlmann-wilsdorf, D. Makel, N. Sondergaard, D. Maribo","doi":"10.1109/33.31429","DOIUrl":"https://doi.org/10.1109/33.31429","url":null,"abstract":"The transition from low-temperature to high-temperature behavior in silver-graphite brushes may be explained either by changes of constriction resistance due to the temperature dependence of electrical resistivity and hardness at negligible film resistivity and one to three contact spots, or by loss of graphite lubrication within the interfacial film. These two interpretations were tested by controlling the contact spot temperature by (1) heating in an oven, and (2) local heat input through friction. Correlated studies of contact resistance, friction, wear rate, wear chip size, and wear chip microstructure, and calculations of contact spot temperatures, favor the second hypothesis. Micrographic evidence suggests that the loss of lubrication occurs through desorption of water vapor from the graphite. It is found that primary wear particles form because of the wedge mechanism and because of cutting by graphite fragments steeply inclined to the interface. Silver fragments may consolidate into secondary wear particles.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122764763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Metallurgical study and tribological properties of edge card connector spring/tab interface","authors":"E. Hsue, R. Bayer","doi":"10.1109/HOLM.1988.16100","DOIUrl":"https://doi.org/10.1109/HOLM.1988.16100","url":null,"abstract":"Summary form only given, as follows. The influence of composite metallurgical structure on the tribological behavior of an edge-card connector was studied. The study centered on the metallurgy of the card tab, which is a multilayer structure consisting of a printed circuit board with an overplated copper layer, nickel, hard gold, and soft gold. These experiments were performed under both dry friction and thin-film polyolester lubricated conditions. The thickness of each was found to alter the frictional characteristics of the surface. The experimental data were found to agree with Finkin's theoretical model for solid-film lubrication. The role of the soft-gold layer was identified as a friction/wear riser, rather than a solid lubricant. It was found that the addition of a minimum layer of lubricant can provide lower friction on contact surface and eliminate fretting wear. The lubricant also made the behavior less sensitive to the metallurgy. When the amount of lubricant was increased the coefficient of friction stayed almost the same from thin-film to flooded conditions. The difference in wear between the dry and thin film lubrication conditions was minor.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123063620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electrical contact to superconductors","authors":"J. Talvacchio","doi":"10.1109/33.19008","DOIUrl":"https://doi.org/10.1109/33.19008","url":null,"abstract":"Electrical contacts to conventional superconductors and high-critical-temperature oxide superconductors are reviewed. The technologically important conventional superconductors considered are Nb and its alloys and compounds, the oxide superconductors are typified by YBa/sub 2/Cu/sub 3/O/sub 7/. Three distinct forms in which the superconductor can be fabricated are considered: thin films for electronics applications, multifilamentary wires for magnets and large-scale applications, and monofilaments or tapes for measurements of the current-carrying capability of a superconducting material. It is concluded that electrical contact to conventional superconductors is relatively straightforward. However, contacting the high-temperature oxide superconductors is difficult not only because the characteristic lengths are short, 0.1 to 10 nm, but because they are strongly dependent on crystal orientation and the oxides tend to be chemically unstable within that distance of the surface.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133048890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of the air pressure on the commutation delay of magnetically driven arcs across a gap or a stop in one of two parallel electrodes","authors":"Yan Wei, Cheng Li-chun","doi":"10.1109/HOLM.1988.16109","DOIUrl":"https://doi.org/10.1109/HOLM.1988.16109","url":null,"abstract":"Research on the effect of the air pressure on the commutation delay of magnetically driven arcs across a gap or a step in one of two parallel electrodes has been conducted using high-speed photography and an optical fiber microcomputer system. The experiments were carried out on different kinds of electrode material, such as brass, copper (cold cathode), and graphite (hot cathode). It is shown that the commutation delay of cold-cathode arcing caused by step or gap on the electrode at low air pressure is directly related to the air pressure and polarity air pressure. A discussion on the experimental results is presented.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131951929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Commutation with metal fiber brushes","authors":"D. Kuhlmann-wilsdorf, D. Alley","doi":"10.1109/33.31430","DOIUrl":"https://doi.org/10.1109/33.31430","url":null,"abstract":"Two principal explanations are given for why metal fiber brushes could be unsuitable for commutation, thereby severely restricting their possible range of technological application. These are (1) high wear rates due to fiber breakage caused by mechanical chopping action of commutator bar edges, and (2) fast erosion at the trailing edges due to arcing, which also affects monolithic brushes, but to a lesser degree. Recent experiments with 50- mu m-diameter bare and silver-plated copper fiber brushes in a protective argon atmosphere, using simulated commutation and running them as working brushes in an electromotor, suggest that these problems may be overcome by the use of much thinner fibers than the >or=100- mu m-diameters that have been used in the past. No fiber breakage was observed, arcing was only moderately stronger than with carbon brushes, and the total dimension-less wear rate in the motor was only about twice that on a polished copper rotor under otherwise comparable conditions.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123395406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. L. Bourguignon, D. P. Agarwal, R. German, S. Farooq, S. Lin
{"title":"Powder metallurgy fabrication of palladium contact alloys","authors":"L. L. Bourguignon, D. P. Agarwal, R. German, S. Farooq, S. Lin","doi":"10.1109/HOLM.1988.16127","DOIUrl":"https://doi.org/10.1109/HOLM.1988.16127","url":null,"abstract":"The authors have combined some novel processing approaches to synthesize a high-performance material using powder metallurgy. A basic Pd-Ag-Cu composition was modified with metalloid additions to attain a fine grain size in combination with rapid solidification techniques. The internal grain structure was ideal for supersolidus sintering, having a dendritic arm spacing on the order of 1 mu m. The result is a fully dense alloy with attractive properties for electrical contact applications, including good conductivity, strength, wear, and corrosion resistance, comparable to or better than traditionally formed palladium-gold-silver-copper alloys. The addition of metalloids to the basic ternary system optimizes properties such as hardness and aids sinterability; yet the alloy can be fabricated without additional expense.<<ETX>>","PeriodicalId":191800,"journal":{"name":"Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114668524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}