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Parts, Hybrids, and Packaging, IEEE Transactions on

Issue 1 • Date March 1975

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Displaying Results 1 - 13 of 13
  • Who's Who in G-PHP

    Page(s): 2
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    Freely Available from IEEE
  • Foreword: Special Issue on Contacts

    Page(s): 3
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    Freely Available from IEEE
  • The Microplastic Behavior of Several Precious Metal Electrical Contact Alloys

    Page(s): 29 - 35
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    Measurements have been made of the microyield and transient creep behavior of three commonly used precious alloy spring contact materials. These tests were done to determine how resistant the alloys were to contact force loss while stored for long times in a stressed condition. The alloys studied were Neyoro G, Paliney 7, and Neyoro 28A. Test temperatures from -58°F(223K) to 212°F(373K) and stresses up to the proportional limit were studied. Neyoro G and Paliney 7 in the age hardened condition were both found to be very resistant to microplastic deformation. Even for stresses equaling the proportional limit, contact force relaxation over several years is predicted to be only a few percent. Neyoro 28A is much less resistant to deformation. View full abstract»

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  • Base Metal Contacts: An Exploratory Study of Separable Connection to Tin-Lead

    Page(s): 35 - 44
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    A study was made of solder plated butt contacts to determine the feasibility of designing separable connectors for high reliability low energy circuits without gold or other precious metals. The chemical reactivity of tin-lead and the penetrability of films that formed on it were determined. It is little degraded by sulfur vapor, 02, SO2, H2S, CO, and NH3. However, films from NO2 and Cl2can grow to large thickness, limited only by time and concentration of the reactant. Corrosion of tin-lead was promoted by a synthetic dust and by salt spray. The penetrability of tin-lead depends on contact pressure, and, owing to creep, on temperature and time. Except at light loads with certain geometries, 0.025 mm (0.001 inch) tin-lead is penetrated nearly to the copper substrate. Reconnection to such spots may be less reliable than to fresh areas, particularly if the contacts are aged between separation and remating. The ability of films on tin-lead to be broken is dependent on contact geometry, load, and wipe. The most effective geometries are cones and short (2.5 ram) wedges having an acute included angle (60°), followed by cones and wedges with an obtuse angle (120°), followed by hemispheres of increasing radius (0.38 to 1.5 mm). The cones and wedges had rounded tips of 0.05 mm radius. The order of merit may be different with thickly plated contacts (much in excess of 0.025 mm); but thick coatings are undesirable on contacts because of their deformability. When good contact is obtained, however, as in the mating of clean surfaces, the ranking of probe geometries in maintaining good contact in aggressive atmospheres is different, with the 1.5 mm radius hemisphere being best. It may be possible to design reliable butt connectors with tin-lead coated contacts for critical applications. However, additional studies need to be undertaken. These include: development of field experience in varied environments, study of long term behavior of mated contacts such as cold welding at elevated temperature, and rematability of contacts that have been aged in corrosive environments between initial use and subsequent matings. View full abstract»

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  • The Molten Metal Bridge Stage of Opening Electrical Contacts

    Page(s): 4 - 10
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    Measurements on the formation and rupture of the molten metal bridge have been made for a number of contact materials, for currents of 8A to 11KA and for contact opening accelerations of 0.4X 103ms-2 to 16.0X 103ms-2. The bridge has three regimes: The initial melting period, a stable period, and an unstable period during which it eventually ruptures. The bridge behavior during these three periods is explained in terms of the interaction between power input into the bridge, hydrodynamic and surface tension elfects, and magnetic pinclh effects. The shortest bridges occur at both the highest current [11KA) and at the lowest current (8A). The longest bridges occur for currents in the range 500A to 1000A. The bridges that show the longest unstable regime occur for opening acceh;rations between 0.5 X 103 ms-2 and 2.0X 103ms-2 View full abstract»

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  • The Effect of Environment on Electrical Contacts: A Discussion at the 1973 Holm Seminar

    Page(s): 57 - 67
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    A central theme of the Holm Seminar in 1973 was the effect of environment on electric contacts. In addition to several technical papers, a panel discussion was conducted on this topic. This paper is a transcript of the discussion. View full abstract»

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  • Design of a Reliable Separable Power Connector With Base Metal Contacts for Telephone Equipment Applications

    Page(s): 45 - 52
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    This paper reviews the technical development of a high reliability base metal connector and illustrates an effort to convert contact research into physical product using design judgment and expedient testing. Topics include normal force, corrosion susceptibility, contact lubrication, crimp termination, and performance testing. View full abstract»

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  • Mercury Contacts-Bridging and Sticking Phenomena

    Page(s): 15 - 20
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    The flow behavior of a viscous substance between two parallel circular contacts, assuming that one of the contacts moves slowly relative to the other, has been analyzed. It has been shown that if the force of separation is less than a certain minimum calculated value, the contacts will stick. The shape of the moving liquid column between the contact surfaces depends upon surface-tension and viscosity. The equilibrium bridge shape, which is defined as the shape of the liquid meniscus between the contacts after the moving contact has stopped, depends on surface-tension and the pressure difference between the fluid and external pressure. This analysis may be useful in the analysis of the flow characteristics of molten metal bridges in electrical contacts and in explaining the behavior of mercury wetted contacts. View full abstract»

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  • Effect of Light Elements (N, C, O) in Tantalum on Tantalum Film Capacitor Properties

    Page(s): 67 - 72
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    The results of this study demonstrate that addition of either carbon or nitrogen to tantalum is desirable not only for meeting the 50 volt dc leakage current criterion used on 230 V tantalum film capacitors, but also for optimizing capacitor reliability. Since both dopants lower the capacitance density by about 1% and 0.35% for each atomic (at',, % of N or C, respectively, the amounts added to tantalum should be kept as low as possible. Two at % of nitrogen or three at % carbon are sufficient to realize their beneficial, effect on capacitor leakage current and capacitor reliability, while addition of oxygen (up to 20 at %) does not improve capacitor quality. Possible effects of nitrogen and carbon doping on the electronic structure (band structure) of the anodic oxide will be discussed. View full abstract»

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  • A Technique for Measuring Net Charge Through Transient Arcs which Occur Across a Contact Breaking an Inductive Load

    Page(s): 53 - 57
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    When a contact interrupts the circuit to a relay winding or another inductive load, severe cathode erosion can occur due to transient arcs associated with high voltage breakdown. Since the volume of this erosion is a function of the net charge conducted through the transient arcs and since the approximate erosion rate per coulomb is known for most contact materials, the contact erosion life can be estimated from a knowledge of the net charge transfer per operation. This paper presents a circuit technique to readily measure the net charge passage per operation without analytical treatment. The circuit uses current probes to monitor the arc current transient, integrates all positive and negative arc current surges separately, and subtracts the two results to yield an output proportional to the net charge flow through all the arcs resulting from the single inductive break. The detection circuitry has a response time of 2.5 ns; however, the holding time. characteristics are such that the output can be readily mete-ed using a digital voltmeter. A plot of measured Palladium cathode erosion under different load conditions versus that predicted using the net charge measuring circuit is presented to illustrate that the correlation is good. View full abstract»

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  • Arc Duration in the Anodic Case

    Page(s): 11 - 14
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    The anode arc is a source of erosion in electrical contacts. The erosion is thought to be proportional to the arc duration. This paper investigates the anodic arc length. A new experimental technique is described to measure arc duration. This method provided better statistics and better time resolution. By applying this technique to different metals, the experimental fact that these arcs are a succession of bursts of fixed duration became evident, The distribution of the number of arcs versus their length can be discussed in terms of the average number of bursts per unit time. Only two parameters for a given metal are sufficient to calculate the average arc length in any given circumstance. A classification o': different metals versus their tendency to sustain long anode arcs is presented. View full abstract»

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  • Intermittent Opens in Electrical Contacts Caused by Mechanically Induced Contact Motion

    Page(s): 72 - 76
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    Shock and vibration have been known to induce contact motion in electrical connectors and thereby cause failures or intermittent disturbances. This paper provides a theoretical analysis of the possibility of obtaining intermittent opens or high resistance caused by mechanically induced contact motion. Intermittent disturbances having time durations of less than one nanosecond are considered. Five possible mechanisms of creating intermit:ent opens are considered. They are: 1. Contact bounce 2. Contact sliding over surface irregularities 3. Contact sliding onto an insulating particle 4. Particle migration through contact area 5. Particle initially in the contact zone. Each possible mechanism is developed fully anc the important parameters are explored. Two actual connectors are evaluated for the possibility of obtaining intermittent opens for each of the five cases. The results of the evaluation are presented in this paper. View full abstract»

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  • A Correlation of Material Toughness, Thermal Shock Resistance, and Microstructure of High Tungsten, Silver-Tungsten Composite Materials

    Page(s): 21 - 29
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    The electrical erosion resistance of composite silver-tungsten materials seems to improve with finer dispersions of the silver and tungsten; however, these materials with the finer dispersions exhibit a higher tendency to fail by catastrophic crack propagation during arc erosion testing. A fracture mechanics approach is taken to determine Gfc, the critical strain .energy release rate for crack extension under plane strain conditions for several compositions and particle size distributions of silver-tungsten materials. A qualitative analysis of resistance to crack propagation in the same materials under severe arcing agrees with the Glc measurements. The fracture toughness of these materials has also been compared to the microstructure by quantitative metallography. A relationship of Glcand the mean free path between tungsten particles has been found to agree on only a porton of the materials. A more complex term involving contiguity, volume fraction silver and mean free path has a good correlation with Glc for all the materials. View full abstract»

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Aims & Scope

This Transaction ceased production in 1977. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

Full Aims & Scope