US Patent 7377690 High trigger temperature lithium intermetallic thermal sensors

A non-electrical intermetallic thermal sensor with trigger temperatures in a range of 360° F. to about 430° F., comprising, a hermetically sealed housing including at least one layer of electronegative metal disposed in the housing, wherein the electronegative metal comprises tin (Sn), and at least one layer of active lithium/magnesium alloy disposed in the housing, wherein each layer(s) of active lithium/magnesium alloy is disposed in abutting interface with each layer(s) of electronegative metal. The intermetallic thermal sensors of the present invention further include at least one diffusion barrier means for inhibiting the diffusion of the active lithium/magnesium alloy layer into the electronegative layer.