AVS 62nd International Symposium & Exhibition
    Applied Surface Science Tuesday Sessions
       Session AS+NS-TuM

Paper AS+NS-TuM5
Characterisation of Glass-To-Metal Interfaces using FIB and STEM

Tuesday, October 20, 2015, 9:20 am, Room 212D

Session: Chemical/Molecular Information from Sub-micron Features and Materials
Presenter: Paul Yates, University of Surrey, UK
Correspondent: Click to Email
Components needing electrical feed through seals are frequently made with glass-to-metal seals and have been for many years. They are often made with stainless steel and silicate glasses but, in order to save weight or for biomedical uses, titanium components are sometimes required. Silicate free glasses are required due to the deleterious reaction that occur between titanium and silicate glasses. The reactions in these systems are not fully understood. When characterising the interfaces and assessing interface quality the standard approach is to use cross sections and characterise with scanning electron microscopy and energy-dispersive x-ray spectroscopy. Although this can reveal micrometer scale processes it can not reveal the nano scale reactions that determine the bonding across the interface in many cases. In this work focussed ion beam milling and scanning transmission electron microscopy are used to attain nano scale information about selected areas of the interface between titanium and a strontium boroaluminate glass-ceramic. Additionally, reactions between the glass-ceramic and Kovar (Fe-29Ni-17Co), a common glass sealing alloy, are characterised. Oxidation of the Kovar surface creates an oxide, characterised with x-ray photoelectron spectroscopy and x-ray diffraction, that improves bonding across the interface compared to the native oxide.