Temperature stable hermetically sealed terminal

A hermetically sealed terminal construction comprising a support member having a base with at least one annular opening therein and a rounded annular shoulder at said opening, a first cylindrical sleeve in the form of an insert having a cylindrical body and an outwardly projecting annular flange surrounding said cylindrical body fitted in said opening and projecting outwardly from at least one side of said base with said annular flange seated against and welded to said base in the area of said annular shoulder, a second cylindrical sleeve surrounding said first sleeve in spaced relation thereto, said second cylindrical sleeve being integrally formed with said base and affixed at one end to said base in the area surrounding said opening, said sleeves defining an annular recess therebetween, an elongated terminal pin extending centrally through said sleeves, and a molded dielectric sealing member securing said terminal pin to said support member, said sealing member being bonded to said terminal pin and to the opposite surfaces of said base with integral portions thereof filling said first sleeve and said annular recess and bonded to the inner and outer surfaces of said sleeves, whereby to effectively increase the area of interface between said sealing member and said support member to thereby inhibit the formation of leakage paths from one side of the support member to the other due to thermal expansion and contraction of the parts.