In an effort to reduce costs associated with automotive electrical connecto
rs, auto manufacturers have looked to tin-coated terminals as an effective
alternative to more expensive gold-coated terminals. Tin, however, is highl
y subject to a wear phenomenon known as fretting corrosion, which increases
the contact resistance and renders the terminals useless. One solution to
minimize fretting corrosion is to increase the terminal normal force. In or
dinary electrical terminals, an increased normal force leads to other probl
ems such as high insertion and removal forces. This work is a continuation
of previous research in which a Ni-Ti shape memory alloy (SMA) coil was dev
eloped in order to increase the high temperature normal force of tin-coated
terminals while maintaining moderate room temperature insertion forces. In
particular, this work addresses the cyclic stability of the SMA coil when
subjected to repeated temperature cycles over extended periods, the maximiz
ation of normal force provided by the coil for the amount of SMA used, and
the long-term high-temperature performance of the SMA. This research has re
sulted in the reduction of the SMA wire diameter by nearly 30%, an increase
in high temperature removal force of the terminal from approximately 20 N
without the SMA to 60 N with it, and an associated reduction in cost by nea
rly 50% over the previous design. To accomplish these improvements, the SMA
composition was changed from 55.1 wt% Ni to 49.7 wt% Ni, and the optimum t
raining temperature for the new composition was found to be 400 degreesC.