Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Abstract In order to evaluate the influence of preform preparation processes on thermal cycle stability glass-to-metal seals, this work embraced two different methods produce for seals. For conventional powder metallurgy (PM) method, molten glass was quenched form frits, then frits were ball milled prepare powders. These powders pressed into green bodies and heated preforms. While casting-machining (CM) cast a graphite mold annealed before accurate machining contrast PM CM method provided an ultralow-porosity structure low porosity seal region. Field emission scanning electron microscope (FE-SEM) conducted investigate bubbles cracks in Furthermore, cycling tests confirmed that these tremendously regions strongly affected To support understanding cracking damage features samples observed by FE-SEM extended finite element (XFEM) used simulate crack initiation propagation. The experimental results demonstrated seals made from preforms occurred region near sealing interface. However, initiated preforms, which verified XFEM simulation results. addition, little degradation leakage rate until 105 cycles, while found after 70 indicating decreased resulting hermetic failure.