Beam Physical Vapor Deposition Research Articles

Characterization of Diamond-like carbon films produced by electron- beam physical vapor deposition

Diamond-like carbon (DLC) films were deposited at 300 °C, 400 °C and 500 °C on 304 L stainless steel substrates by electron-beam physical vapor deposition. The obtained coatings were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy and X-ray photo electron spectroscopy (XPS). The FTIR results demonstrate the presence of sp3 and sp2 vibrations corresponding to a diamond-like carbon phase and graphite, respectively. Raman and XPS analysis confirm a presence of high quantity of CC bonds in sp3 state in the deposited DLC films. Increasing the substrate temperature from 300 °C to 500 °C led to a decreasing of the hardness from 4.5 GPa to 3.2 GPa.

High-Temperature Creep Degradation of the AM1/NiAlPt/EBPVD YSZ System

The failure mechanisms of a NiAlPt/electron beam physical vapor deposition yttria-stabilized-zirconia thermal barrier coating system deposited on the AM1 single crystalline substrate have been investigated under pure creep conditions in the temperature range from 1273 K to 1373 K (1000 °C to 1100 °C) and for durations up to 1000 hours. Doubly tapered specimens were used allowing for the analysis of different stress states and different accumulated viscoplastic strains for a given creep condition. Under such experiments, two kinds of damage mechanisms were observed. Under low applied stress conditions (i.e., long creep tests), microcracking is localized in the vicinity of the thermally grown oxide (TGO). Under high applied stress conditions, an unconventional failure mechanism at the substrate/bond coat interface is observed because of large creep strains and fast creep deformation, hence leading to a limited TGO growth. This unconventional failure mechanism is observed although the interfacial bond coat/top coat TGO thickening is accelerated by the mechanical applied stress beyond a given stress threshold.