Glass-Ceramic to Metal Sealing with New Ni-Pt-Re Alloy Electrical Contact Pins

Glass-ceramic (GC)-to-metal seals provide a hermetic barrier in components with long-term high-reliability requirements. A GC-to-metal materials system is being developed with a stainless steel outer shell, a lithium borosilicate GC, and a new pin alloy composed of Ni-Pt-Re. This novel materials system improves thermal processing margin and reduces detrimental reactions between the GC and pin alloy during sealing compared to legacy materials systems. A broad processing window has been developed -- hermetic assemblies are produced with GC thermal expansion coefficients between 12 and 16 ppm/deg C. Hermeticity is maintained after thermal cycling exposure and high temperature/high pressure static experiments as well. The GC/pin interface microstructure exhibited minimal interaction between the pin and GC with only a thin layer of Zn-rich material formed at the interface. Finite element modeling predictions of axial tensile stresses correlate well with observed microcracking in the radial direction from the pin into the GC. Other testing and analysis of this new GC-to-metal seal system, including pin solderability and pin microhardness, will be discussed.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.