Laser glazing is a process in which a thin layer of surface material of a solid is melted, then rapidly cooled; this can be achieved by moving a sample across a focused laser beam. A brief study of some properties of electrodeposited gold that are important to electric contacts was made in which laser glazing was performed on nickel and copper-nickel-tin substrates. It was found that the intrinsic porosity of thin gold coatings and their resistance to abrasive wear were degraded by laser glazing compared to these characteristics when unglazed substrates were used. This can be ascribed to the surface roughening and waviness, and to the softening produced by the thermal treatment.<>
{"title":"Wear and porosity of electrodeposited gold contacts: the effect of laser glazing the substrate metal","authors":"M. Antler, M.H. Drozdowicz","doi":"10.1109/HOLM.1989.77928","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77928","url":null,"abstract":"Laser glazing is a process in which a thin layer of surface material of a solid is melted, then rapidly cooled; this can be achieved by moving a sample across a focused laser beam. A brief study of some properties of electrodeposited gold that are important to electric contacts was made in which laser glazing was performed on nickel and copper-nickel-tin substrates. It was found that the intrinsic porosity of thin gold coatings and their resistance to abrasive wear were degraded by laser glazing compared to these characteristics when unglazed substrates were used. This can be ascribed to the surface roughening and waviness, and to the softening produced by the thermal treatment.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128969119","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}
S. Simko, A. Lee, S. Gaarenstroom, A. A. Dow, C. A. Wong
The reactions of atmospheric pollutants with silver-based switching contact materials produce corrosion products which can adversely affect the contact's electrical behavior. In the present study, three silver-based contact materials-Ag/Cu/Ni, Ag/Ni, and Ag/MgO/NiO-were exposed to an accelerated corrosion environment containing SO/sub 2/, H/sub 2/S, NO/sub 2/, and Cl/sub 2/. An elevated temperature and high humidity were also maintained. Both electrical degradation and corrosion film growth characteristics were studied as functions of exposure time. It was found that contact resistance increases rapidly with the initial corrosion film formation, silver chlorides and silver sulfides are the major corrosion products formed in the accelerated aging environment, and corrosion film thickness and uniformity have strong effects on contact resistance.<>
{"title":"Film formation on silver-based switching contacts","authors":"S. Simko, A. Lee, S. Gaarenstroom, A. A. Dow, C. A. Wong","doi":"10.1109/HOLM.1989.77936","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77936","url":null,"abstract":"The reactions of atmospheric pollutants with silver-based switching contact materials produce corrosion products which can adversely affect the contact's electrical behavior. In the present study, three silver-based contact materials-Ag/Cu/Ni, Ag/Ni, and Ag/MgO/NiO-were exposed to an accelerated corrosion environment containing SO/sub 2/, H/sub 2/S, NO/sub 2/, and Cl/sub 2/. An elevated temperature and high humidity were also maintained. Both electrical degradation and corrosion film growth characteristics were studied as functions of exposure time. It was found that contact resistance increases rapidly with the initial corrosion film formation, silver chlorides and silver sulfides are the major corrosion products formed in the accelerated aging environment, and corrosion film thickness and uniformity have strong effects on contact resistance.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117211648","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}
The influence of the metallic-phase arc discharge on contact performance was studied for breaking Ag contacts. Measured parameters were whole arc duration (metallic-phase plus gaseous-phase arc duration), metallic-phase arc duration, contact resistance, bridge energy, and electrode material mass change. The tests were carried out under the various conditions of air pressure and contact current. The experimental results showed that the contact resistance increased when the arc duration in the metallic-phase arc region grew, and it was high and almost became constant when the arc reached the transition border to the gaseous phase. The material loss and transfer is log-proportional to the accumulated metallic-phase arc duration, irrespective of the air pressure condition. The effect of whole arc duration was not clear in the material mass change when the air pressure was varied. From many test results, it is concluded that the material mass change mainly depends on the metallic-phase arc rather than the whole arc duration. This means that the metallic-phase arc duration affects the material loss and transfer and the constant resistance, while the gaseous-phase arc has little influence.<>
{"title":"Role of the metallic phase arc discharge on arc erosion in Ag contacts","authors":"H. Sone, T. Takagi","doi":"10.1109/HOLM.1989.77920","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77920","url":null,"abstract":"The influence of the metallic-phase arc discharge on contact performance was studied for breaking Ag contacts. Measured parameters were whole arc duration (metallic-phase plus gaseous-phase arc duration), metallic-phase arc duration, contact resistance, bridge energy, and electrode material mass change. The tests were carried out under the various conditions of air pressure and contact current. The experimental results showed that the contact resistance increased when the arc duration in the metallic-phase arc region grew, and it was high and almost became constant when the arc reached the transition border to the gaseous phase. The material loss and transfer is log-proportional to the accumulated metallic-phase arc duration, irrespective of the air pressure condition. The effect of whole arc duration was not clear in the material mass change when the air pressure was varied. From many test results, it is concluded that the material mass change mainly depends on the metallic-phase arc rather than the whole arc duration. This means that the metallic-phase arc duration affects the material loss and transfer and the constant resistance, while the gaseous-phase arc has little influence.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124545301","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}
It is noted that contact resistance increase in a contaminated atmosphere is generally attributed to corrosion film growth. However, its usual measurement does not reveal the basic conduction phenomena which occur at the contact point. Results on electrical conduction through Cu/sub 2/S films from 430 to 4500 AA thick grown on copper samples in a controlled atmosphere were reported. The study is based on the analysis of the current-voltage characteristics of the contact point using a fully automatic device which avoids electrical or mechanical breakdowns. It is shown that the contact point has an equivalent circuit composed of serial elements: diode, thermoelectric voltage, and contact resistance. The diode parameters resulting from the junction between Cu/sub 2/S (semiconductor) and copper (metal) are determined. The main result is a relationship between reverse current density and the thickness of the film that can explain and predict film breakdown. Furthermore, dynamic contact resistance is shown to depend on current level and direction; its limit (static resistance) is reached with a higher current level value or with gold-flashed film.<>
{"title":"Electrical conduction through Cu/sub 2/S corrosion films on copper contacts","authors":"N. Ben Jemaa, J. Queffelec, D. Travers","doi":"10.1109/HOLM.1989.77934","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77934","url":null,"abstract":"It is noted that contact resistance increase in a contaminated atmosphere is generally attributed to corrosion film growth. However, its usual measurement does not reveal the basic conduction phenomena which occur at the contact point. Results on electrical conduction through Cu/sub 2/S films from 430 to 4500 AA thick grown on copper samples in a controlled atmosphere were reported. The study is based on the analysis of the current-voltage characteristics of the contact point using a fully automatic device which avoids electrical or mechanical breakdowns. It is shown that the contact point has an equivalent circuit composed of serial elements: diode, thermoelectric voltage, and contact resistance. The diode parameters resulting from the junction between Cu/sub 2/S (semiconductor) and copper (metal) are determined. The main result is a relationship between reverse current density and the thickness of the film that can explain and predict film breakdown. Furthermore, dynamic contact resistance is shown to depend on current level and direction; its limit (static resistance) is reached with a higher current level value or with gold-flashed film.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116319263","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}
Metallic-phase duration and transition ratio to gaseous phase were investigated for Pd contacts under the variation of closed contact current I/sub o/, load inductance L (0.2-2.3 mH), and source voltage E (6-48 V). The results obtained were compared with results for Ag and W contacts, reported for the same circuit conditions. Experiments have revealed that the boundary closed contact current I/sub ob/, at which the transition ratio is 50%, decreases with increase of L and E in the same manner as for Ag and W contacts. The metallic phase duration t/sub m/ was found to increase rapidly with I/sub o/ in the vicinity of I/sub ob/, in a similar manner to Ag contacts. For Pd contacts, the degree of slope change of the t/sub m/-I/sub o/ curve, at the point where the transition ratio attains about 100%, tends to be larger than that for W and smaller than that for Ag.<>
{"title":"Transition boundary from metallic to gaseous phase in Pd break arc","authors":"K. Yoshida, A. Takahashi","doi":"10.1109/HOLM.1989.77939","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77939","url":null,"abstract":"Metallic-phase duration and transition ratio to gaseous phase were investigated for Pd contacts under the variation of closed contact current I/sub o/, load inductance L (0.2-2.3 mH), and source voltage E (6-48 V). The results obtained were compared with results for Ag and W contacts, reported for the same circuit conditions. Experiments have revealed that the boundary closed contact current I/sub ob/, at which the transition ratio is 50%, decreases with increase of L and E in the same manner as for Ag and W contacts. The metallic phase duration t/sub m/ was found to increase rapidly with I/sub o/ in the vicinity of I/sub ob/, in a similar manner to Ag contacts. For Pd contacts, the degree of slope change of the t/sub m/-I/sub o/ curve, at the point where the transition ratio attains about 100%, tends to be larger than that for W and smaller than that for Ag.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128819901","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}
The electrical properties of a stationary electric contact are closely related to phenomena occurring in the very small contact spots of the interface. Contact spots in aluminium-aluminium interfaces that have passed heavy direct currents have been studied. The size, shape, and appearance of the spot fractures were found to be correlated to the surface roughness and to the recorded voltage and resistance characteristics. Rough contact surfaces caused irregularly shaped contact spots to develop, while high and unstable resistances were always associated with large contact spots. The latter observation indicates that the electrical conductivity of the contact spots has been reduced by the electrical stresses: the spots have aged. Aging of a contact point leads to the formation of new current paths through the interface, in the vicinity of the original ones. The aging rate increases rapidly with increasing voltage drop across the interface.<>
{"title":"Experimental study of the conducting spots in aluminium contact interfaces","authors":"M. Runde, E. Hodne, B. Tøtdal","doi":"10.1109/HOLM.1989.77941","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77941","url":null,"abstract":"The electrical properties of a stationary electric contact are closely related to phenomena occurring in the very small contact spots of the interface. Contact spots in aluminium-aluminium interfaces that have passed heavy direct currents have been studied. The size, shape, and appearance of the spot fractures were found to be correlated to the surface roughness and to the recorded voltage and resistance characteristics. Rough contact surfaces caused irregularly shaped contact spots to develop, while high and unstable resistances were always associated with large contact spots. The latter observation indicates that the electrical conductivity of the contact spots has been reduced by the electrical stresses: the spots have aged. Aging of a contact point leads to the formation of new current paths through the interface, in the vicinity of the original ones. The aging rate increases rapidly with increasing voltage drop across the interface.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128524009","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}
Sliding electric contact experiments show that, in dusty environments, liquid lubricants appear to perform better than wax lubricants. Experimental and theoretical analysis indicates that high permittivity of the lubricants plays an important role in attracting dust. The mixture of dust particles and wax could be very harmful to the contact, especially under low normal force. Dust particles floated on the surface of liquid droplets appear to have high mobility, which reduces the dust problem. Electric current flowing through the contacts possibly melts the wax and decreases contact resistance. On the contrary, electric current weakens the mobility and floating ability of dust on the liquid surface, which leads to an increase in resistance. Simply reducing the contact size can cause the embedding of dust into wear tracks in low normal force applications.<>
{"title":"Dust effects on various lubricated sliding contacts","authors":"Ji-gao Zhang, Chun-Hui Mei, Xiao-Min Wen","doi":"10.1109/HOLM.1989.77918","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77918","url":null,"abstract":"Sliding electric contact experiments show that, in dusty environments, liquid lubricants appear to perform better than wax lubricants. Experimental and theoretical analysis indicates that high permittivity of the lubricants plays an important role in attracting dust. The mixture of dust particles and wax could be very harmful to the contact, especially under low normal force. Dust particles floated on the surface of liquid droplets appear to have high mobility, which reduces the dust problem. Electric current flowing through the contacts possibly melts the wax and decreases contact resistance. On the contrary, electric current weakens the mobility and floating ability of dust on the liquid surface, which leads to an increase in resistance. Simply reducing the contact size can cause the embedding of dust into wear tracks in low normal force applications.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126900447","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}
The authors have previously reported (see Proc. 14th Int. Conf. on Electric Contacts, p.233-7, 1988) that, when Pd contacts are operated using mechanical break-make actions without switching load current in the air, palladium-oxides are formed on the contact surfaces by mechanochemical reaction caused by mechanical actions, and they cause serious deterioration of contact resistance. In the present work, the formation of the same products is reported on Ag-Pd70% and Ag-Pd50% contacts after tests involving operation 100000 times. Significant increase of contact resistance, however, was not observed. On the other hand, it is also found that the products show nonlinearity of contact resistance according to measuring current in both dynamic and static measurement. Temperature calculation shows that softening of the electrodes is not the main cause of the observed phenomenon. Thermal dissolution of the products is proposed as a possible cause.<>
作者以前曾报道(见第14编)。con . on Electric Contacts, p.233-7, 1988)指出，在没有在空气中开关负载电流的情况下，使用机械开断动作操作Pd触点时，由于机械动作引起的机械化学反应，在触点表面形成了氧化钯，导致触点电阻严重恶化。在本工作中，报告了Ag-Pd70%和Ag-Pd50%触点经过10万次操作试验后形成相同产品。然而，没有观察到接触电阻的显著增加。另一方面，在动态和静态测量中也发现产品的接触电阻随测量电流的变化呈现非线性。温度计算表明，电极的软化不是观察到的现象的主要原因。产物的热溶解被认为是可能的原因。
{"title":"Formation of palladium-oxides by mechanochemical reaction on Pd and Ag-Pd alloy contacts","authors":"M. Hasegawa, K. Sawa","doi":"10.1109/HOLM.1989.77938","DOIUrl":"https://doi.org/10.1109/HOLM.1989.77938","url":null,"abstract":"The authors have previously reported (see Proc. 14th Int. Conf. on Electric Contacts, p.233-7, 1988) that, when Pd contacts are operated using mechanical break-make actions without switching load current in the air, palladium-oxides are formed on the contact surfaces by mechanochemical reaction caused by mechanical actions, and they cause serious deterioration of contact resistance. In the present work, the formation of the same products is reported on Ag-Pd70% and Ag-Pd50% contacts after tests involving operation 100000 times. Significant increase of contact resistance, however, was not observed. On the other hand, it is also found that the products show nonlinearity of contact resistance according to measuring current in both dynamic and static measurement. Temperature calculation shows that softening of the electrodes is not the main cause of the observed phenomenon. Thermal dissolution of the products is proposed as a possible cause.<<ETX>>","PeriodicalId":441734,"journal":{"name":"Proceedings of the Thirty Fifth Meeting of the IEEE Holm Conference on Electrical Contacts","volume":"3 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":"124546661","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}
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