On the optical properties of bismuth oxide thin films prepared by pulsed laser deposition

The optical properties of bismuth oxide films prepared by pulsed laser deposition (PLD), absorption in the photon energy range 2.50-4.30 eV and optical functions (n, k, epsilon(1), and epsilon(2)) in the domain 3.20-6.50 eV, have been investigated. As-prepared films (d = 0.05-1.50 mum) are characterized by a mixture of polycrystalline and amorphous phases. The fundamental absorption edge is described by direct optical band-to-band transitions with energies 2.90 and 3.83 eV The dispersion of the optical functions provided values of 4.40-6.25 eV for electron energies of respective direct transitions. In the spectral range 400-1000 nm, bismuth oxide films show a normal dispersion, which can be interpreted in the frame of a single oscillator model. (C) 2004 Elsevier B.V. All rights reserved.

Ferroelectricity in epitaxial pulsed laser deposited bismuth-layered perovskite thin films of different crystallographic orientations

Epitaxial thin films Of various bismuth-layered perovskites SrBi(2)Ta(2)O(9), Bi(4)Ti(3)O(12), BaBi(4)Ti(4)O(15), and Ba(2)Bi(4)Ti(5)O(18) were deposited by pulsed laser deposition onto epitaxial conducting LaNiO(3) or SrRuO(3) electrodes on single crystalline SrTiO(3) substrates with different crystallographic orientations or on top of epitaxial buffer layers on (100) silicon. The conductive perovskite electrodes and the epitaxial ferroelectric films are strongly influenced by the nature of the substrate, and bismuth-layered perovskite ferroelectric films with mixed (100), (110)- and (001)-orientations as well as with uniform (001)-, (116)- and (103)- orientations have been obtained. Structure and morphology investigations performed by X-ray diffraction analysis, scanning probe microscopy, and transmission electron microscopy reveal the different epitaxial relationships between films and substrates. A clear correlation of the crystallographic orientation of the epitaxial films with their ferroelectric properties is illustrated by macroscopic and microscopic measurements of epitaxial bismuth-layered perovskite thin films of different crystallographic orientations.

Lead-bismuth eutectic corrosion behaviors of ferritic/martensitic steels in low oxygen concentration environment

In order to investigate the compatibility of candidate structural materials with liquid metals, two kinds of ferritic/martensitic steels were chosen to contact with lead–bismuth eutectic in sealed quartz–glass tubes. The corrosion exposures were for 500 and 3000 h. Results showed that the oxidation layer and carbide dissolution layer on the two steels grew with contact time under oxygen unsaturated condition. Short-term corrosion behavior of a newly developed steel showed better lead–bismuth eutectic corrosion resistance than T91 at 873 K.

Effects of temperature and strain rate on the tensile behaviors of SIMP steel in static lead bismuth eutectic

In order to assess the susceptibility of candidate structural materials to liquid metal embrittlement, this work investigated the tensile behaviors of ferritic-martensitic steel in static lead bismuth eutectic (LBE). The tensile tests were carried out in static lead bismuth eutectic under different temperatures and strain rates. Pronounced liquid metal embrittlement phenomenon is observed between 200 °C and 450 °C. Total elongation is reduced greatly due to the liquid metal embrittlement in LBE environment. The range of ductility trough is larger under slow strain rate tensile (SSRT) test.