Potential Effects of the World Economy on Contact Resistance

摘要

The effects on contact resistance of dormant storage of silver and copper rivet contacts for extended periods and of exposure to elevated temperatures were evaluated. Storage of contacts for periods of 1 month or less caused limited increase in contact resistance. Storage for periods of a year led to severe and unacceptable increases in contact resistance. The increased resistance in both materials was associated with visible optical discoloration of the contact surfaces. For comparison theoretical calculated contact resistance values were calculated and compared to data from clean, ready to use contacts. Heating to over 200°C caused some increase in the contact resistance of copper contacts while a variety of silver materials showed little increase. Nickel parts, although having higher resistance than the other materials in the clean condition, showed less increase in resistance than copper after the high temperature exposure. Contact resistance is an important contact property in itself which is affected by holding periods and heating. It can also be used as a diagnostic tool to characterize the cleanliness, consistency and functionality of contact surfaces for electrical contact applications.