On the Relationship between Contact Resistance and Load Force for Electrode Materials with Rough Surfaces.

Higher contact resistance not only increases power consumption and temperature rise but also causes undesirable interconnectivity between electrode materials, which further influences the electrical lifespan and reliability of switching devices. However, relevant studies on the relationship between contact resistance and load force, and on the reduction of contact resistance by controlling the micro-structure of rough surfaces, especially for electrode materials with larger (root mean square) values, are very limited. In this study, the contact resistance calculation method, based on classical Holm theory in combination with the elastic and plastic deformation, was reviewed.

Contact welding strength measurement for metal electrode materials conducting inrush electrical current.

Contact welding is considered the major failure mechanism for electromechanical switch applications. There has been increasing demand to research the measurement method to characterize the anti-welding ability of metal electrode materials. In this paper, the contact welding phenomenon of closed electrodes is made to reoccur by using our novel designed test rig.

Modeling and Experimental Verification of Material Welding Characteristics for Low Current Switching Devices.

Material welding failure considerably influences the electrical lifetime and reliability of low current switching devices. However, relevant studies on methods for calculating the threshold welding current and welding area under milli-Newton scale load forces are very limited. In this paper, the welding characteristics of metal material, including the threshold welding current, welding area and welding force are studied by using theoretical calculations and experiments.

Investigations of the contact bounce behaviors and relative dynamic welding phenomena for electromechanical relay.

Dynamic welding, being the principal mechanism of sticking failure, correlates closely with the contact bounce of electromechanical relay. The typical waveforms of dynamic contact force and contact voltage at making and breaking process are obtained with the use of a new designed test rig. The variations in bounce time, bounce numbers, last bounce duration, and relevant welding force are investigated in the electrical endurance test.

Electrical properties and behaviors of cuprous oxide cubes under high pressure.

An accurate in situ electrical resistivity measurement of cuprous oxide cubes has been conducted in a diamond anvil cell at room temperature with pressures up to 25 GPa. The abnormal electrical resistivity variation found at 0.7-2.

Note: The effect of sample insulation on experiment precision of resistivity measurement in a diamond anvil cell.

By use of electrical field analysis method, the accuracy of electrical resistivity measurement with the van der Pauw method in a diamond anvil cell (DAC) was investigated for the situation that sample and gasket were electrically shorted. It is revealed that metal gasket could not be used in electrical measurement in DAC if the inside wall of the sample chamber was not insulated. When the shorted area was less than 20% of the inside wall of the sample chamber, the relative error was smaller than 10%.

In situ impedance measurements in diamond anvil cell under high pressure.

Two-electrode configuration was developed for in situ electrical impedance detecting on diamond anvil cell under high pressure. The metal gasket was used as one electrode and the risk coming from electrical short between sample and interside wall of the gasket was eliminated. The configuration was evaluated and proved to be effective by measuring the electric impedance of nanocrystalline ZnS under high pressure.