Strength-Flaw Relationship of Corroded Pristine Silica Studied by Atomic Force Microscopy

1994 ◽  
Vol 332 ◽  
Author(s):  
Qian Zhong ◽  
Daryl Inniss ◽  
Charles R. Kurkjian
Keyword(s):  
Optical Fibers ◽  
Strength Degradation ◽  
Force Microscopy ◽  
Silica Glasses ◽  
Spatially Resolved ◽  
Atomic Force ◽  
Silica Fibers ◽  
Surface Flaws ◽  
Relationship Of ◽  
Microscopic Surface

ABSTRACTGlass strength is controlled by microscopic surface flaws. Attempts to quantify the strengthflaw relationship for corroded silica fibers have been unfruitful, principally because of the difficulty in identifying the nanometer-sized, strength-controlling flaws on a uniformly corroded surface. In this paper, studies on corrosion of pristine silica optical fibers by HF vapor are presented. The HF-treated fibers exhibit strength degradation and contain well-defined, spatially-resolved surface flaws, which are characterized with an atomic force microscope. Excellent strength agreement is obtained for all chemically corroded fibers when the flaws are modeled as partially embedded hemispheres (i.e., blunt flaws). The implication of these results to the corrosion and fatigue process of silica glasses is discussed, since all previous analyses have assumed the strength-controlling flaws to be sharp.

High-resolution transmission electron microscopic investigations of molybdenum thin films on faceted α-Al2O3

2005 ◽  
Vol 38 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Leonore Wiehl ◽  
Jens Oster ◽  
Michael Huth
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Epitaxial Relationship ◽  
Electron Microscopic ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Α Al2o3 ◽  
Relationship Of

Epitaxially grown Mo films on a faceted corundum (α-Al2O3)mplane were investigated by transmission electron microscopy. Low- and high-resolution images were taken from a cross-section specimen cut perpendicular to the facets. It was possible to identify unambiguously the crystallographic orientation of these facets and explain the considerable deviation (∼10°) of the experimental interfacet angle, as measured with atomic force microscopy (AFM), from the expected value. For the first time, proof is given for a smooth \{10\bar{1}1\} facet and a curvy facet with orientation near to \{10\bar{1}\bar{2}\}. Moreover, the three-dimensional epitaxial relationship of an Mo film on a faceted corundummsurface was determined.

Atomic Force Microscopy Studies on Optical Fibers

1997 ◽  
pp. 179-188
Author(s):  
M. John Matthewson ◽  
Vincenzo V. Rondinella ◽  
James Colaizzi
Keyword(s):  
Atomic Force Microscopy ◽  
Optical Fibers ◽  
Force Microscopy ◽  
Atomic Force

Spatially resolved electrical measurements of SiO2 gate oxides using atomic force microscopy

1993 ◽  
Vol 62 (7) ◽  
pp. 786-788 ◽  
Author(s):  
M. P. Murrell ◽  
M. E. Welland ◽  
S. J. O’Shea ◽  
T. M. H. Wong ◽  
J. R. Barnes ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electrical Measurements ◽  
Gate Oxides ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force

Nanoscale Modification Of Amorphous Diamond-Like Carbon Film Surfaces

1995 ◽  
Vol 416 ◽  
Author(s):  
T. W. Mercer ◽  
N. J. Dinardo ◽  
J. P. Sullivan ◽  
T. A. Friedmann ◽  
M. P. Siegal ◽  
...  
Keyword(s):  
Carbon Film ◽  
Carbon Films ◽  
Scanning Tunneling ◽  
Plasmon Energy ◽  
Electron Dose ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force ◽  
Potential Applications ◽  
Electron Energy Loss

ABSTRACTScanning Tunneling and Atomic Force Microscopy (STM, AFM) of amorphous tetrahedral carbon films (a-tC) film surfaces grown by pulsed laser deposition indicate extreme flatness and uniform electronic properties.1 This is consistent with the observed predominance of sp3 (diamond-like) bonding in these materials.2 Potential applications of a-tC films may be enhanced with the ability to modify their surfaces on the nanoscale. Exploiting the metastable nature of the sp3 hybridized state of carbon, the high flux electron beam from an STM tip was used to modify ˜100 nm regions; processing in air or in vacuum produces similar results. STM and AFM maps of the modified regions indicate stable morphologic and electronic structures consistent with a local transformation to sp2 (graphitic) hybridization. Surface potentiometric mapping of these regions indicates a correlation between electron dose and a lowering of the surface potential. In addition, spatially-resolved electron energy loss spectroscopy of the modified areas performed with a Scanning Auger Microscope shows plasmon energy shifts that confirm an elevated sp2 content in the modified regions.3

Activation Energy for Strength Degradation of Fused Silica Optical Fibers

1998 ◽  
Vol 531 ◽  
Author(s):  
Yunn-Shin Shiue ◽  
M. John Matthewson
Keyword(s):  
Activation Energy ◽  
Optical Fibers ◽  
Pure Water ◽  
Strength Degradation ◽  
Fused Silica ◽  
Static Fatigue ◽  
Buffer Solution ◽  
Silica Fibers ◽  
Apparent Activation Energies ◽  
Stress Dependent

AbstractThe strength degradation behavior of fused silica optical fiber is well known to be sensitive to the temperature and an apparent activation energy can be determined. In addition, it has been observed that the activation energy also depends on the applied stress and the nature of the environment. However, no consistent model for this behavior has emerged. We propose a chemical kinetics model which accounts for the temperature dependence of the dissociation of water which predicts that degradation should be faster in pH 7 buffer than in pure water. Static fatigue of fused silica fibers in both water and pH 7 buffer solution has been carefully studied as a function of temperature to test the model. The apparent activation energies are stress dependent, and, while the dependency is not clear, different environments give different dependencies. These observations support the proposed model.

Preparation of epitaxial SrBi2Nb2O9 and SrBi2Ta2O9 thin films by the coating-pyrolysis process

1999 ◽  
Vol 14 (7) ◽  
pp. 3090-3095 ◽  
Author(s):  
T. Nagahama ◽  
T. Manabe ◽  
I. Yamaguchi ◽  
T. Kumagai ◽  
S. Mizuta ◽  
...  
Keyword(s):  
Thin Films ◽  
Epitaxial Films ◽  
Yttria Stabilized Zirconia ◽  
Pyrolysis Process ◽  
Stabilized Zirconia ◽  
Epitaxial Relationship ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polycrystalline Thin Films ◽  
Relationship Of

Epitaxial and polycrystalline thin films of bismuth layer-structured ferroelectrics, SrBi2Nb2O9 (SBN) and SrBi2Ta2O9 (SBT), were prepared on single-crystal SrTiO3(001) and polycrystalline yttria-stabilized zirconia substrates, respectively, by the coating-pyrolysis process. The epitaxial relationship of the films and substrates was SBN, SBT (001)//SrTiO3(001) and SBN, SBT [100]//SrTiO3[100],[010], where pseudotetragonal indices were adopted for SBN and SBT. The lattices of the epitaxial films were found to be slightly strained owing to stress from the substrate. Atomic force microscopy observations showed that the epitaxial films as well as polycrystalline films consisted of round-shaped, islandlike grains of submicrometer size.

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