Normal force reduction in electronic circuits

Elevated temperature heat-aging tests were performed on dual cantilever beam gold-plated-over-nickel, phosphor bronze electrical contacts. The normal force provided by the beam was directly measured before and after heat aging. A series of curves relating change of normal force with time was obtained for the temperature range 100-200°C. These curves showed that the normal force reduces with time. The rate of this reduction was found to increase with elevated temperature. The results of the tests are used to develop an empirical relationship for the behavior of the normal force with time and temperature