Bonding and Stability of Metal/Ceramic Interfaces

1998 ◽  
Vol 4 (S2) ◽  
pp. 768-769
Author(s):  
U. Alber ◽  
R. Schweinfest ◽  
M. Riihle
Keyword(s):  
Materials Science ◽  
Mechanical Stability ◽  
Model System ◽  
Interface Model ◽  
Bending Tests ◽  
Four Point Bending ◽  
Analytical Electron ◽  
Metal Ceramic ◽  
Pure Cu ◽  
Ceramic Interfaces

Metal/ceramic interfaces play a crucial role in materials science and for various industrial purposes. In technical applications these interfaces are often exposed to high temperatures and different atmospheres. This often results in a change of the mechanical stability via the morphology and electronic structure of the interfaces. We present a comprehensive analytical electron microcopy (AEM) and fracture mechanics study of this connection on a metal/ceramic-interface model system: Cu/ α-Al2O3.The specimens were produced by UHV diffusion bonding of bulk Cu to (α-Al2O3 single crystals. Two different Cu materials were used, either pure Cu (noted: Cu) or Cu containing 83±12 ppm oxygen (noted: Cu(O)). After bonding the interfaces were annealed in an oxygen partial pressure at 1000°C between 20 and 120 h. Four point bending tests showed an increase of the fracture energy for the Cu(O)/α -Al2O3-interfaces compared to the Cu(O)/α-Al2O3-interfaces by a factor of 5±2.

Chemistry and Structure of Internal Interfaces in Inorganic Materials

1996 ◽  
Vol 453 ◽  
Author(s):  
M. Rühle ◽  
A. Recnik ◽  
M. Ceh
Keyword(s):  
Materials Science ◽  
Structural Information ◽  
Inorganic Materials ◽  
Polycrystalline Materials ◽  
Formation Mechanisms ◽  
Materials Properties ◽  
Metal Ceramic ◽  
Ceramic Interfaces ◽  
Modern Instrumentation ◽  
Detailed Chemical

AbstractPhysical properties of polycrystalline materials are controlled by intergranular as well as intragranular effects. In most cases materials' properties adhere to the bonding character of internal interfaces and plasticity of bulk parts. The nature of interfaces is in general difficult to understand, although they have far reaching consequences to overall properties of processed materials. To properly understand the effects brought by such interfaces one has to correlate particular properties with their local chemistry and structure. The availability of modern instrumentation that can provide a detailed chemical and structural information down to a subnanometer scale has helped greatly in tackling many fundamental problems in materials science. Our systematic studies of several metal/ceramic and ceramic/ceramic interfaces has given us a wealth of information that brings us closer to the answer on the formation mechanisms of the internal interfaces and other structural transformations in materials.

A library of convergent-beam electron diffraction patterns

1986 ◽  
Vol 44 ◽  
pp. 688-691
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Diffraction ◽  
Materials Science ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Transmission Electron ◽  
Yield Information ◽  
Analytical Electron ◽  
Diffraction Patterns ◽  
Convergent Beam ◽  
Electron Energy Loss

One of the most important advancements of the transmission electron microscopy (TEM) in recent years has been the development of the analytical electron microscope (AEM). The microanalytical capabilities of AEMs are based on the three major techniques that have been refined in the last decade or so, namely, Convergent Beam Electron Diffraction (CBED), X-ray Energy Dispersive Spectroscopy (XEDS) and Electron Energy Loss Spectroscopy (EELS). Each of these techniques can yield information on the specimen under study that is not obtainable by any other means. However, it is when they are used in concert that they are most powerful. The application of CBED in materials science is not restricted to microanalysis. However, this is the area where it is most frequently employed. It is used specifically to the identification of the lattice-type, point and space group of phases present within a sample. The addition of chemical/elemental information from XEDS or EELS spectra to the diffraction data usually allows unique identification of a phase.

Development of 200kV ultrahigh-resolution analytical electron microscope

1989 ◽  
Vol 47 ◽  
pp. 108-109
Author(s):  
T. Kaneyama ◽  
M. Naruse ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
Electron Microscope ◽  
Optical Constants ◽  
Materials Science ◽  
Objective Lens ◽  
The Finite Element Method ◽  
Ultrahigh Resolution ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Characteristic Features ◽  
Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

Development of high-performance objective lens polepiece for ultrahigh resolution Analytical Electron Microscope

1993 ◽  
Vol 51 ◽  
pp. 254-255
Author(s):  
K. Fukushima ◽  
T. Kaneyama ◽  
F. Hosokawa ◽  
H. Tsuno ◽  
T. Honda ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Performance ◽  
Open Space ◽  
Materials Science ◽  
Objective Lens ◽  
Ultrahigh Resolution ◽  
Science Field ◽  
Specimen Holder ◽  
Analytical Electron ◽  
Analytical Electron Microscope

Recently, in the materials science field, the ultrahigh resolution analytical electron microscope (UHRAEM) has become a very important instrument to study extremely fine areas of the specimen. The requirements related to the performance of the UHRAEM are becoming gradually severer. Some basic characteristic features required of an objective lens are as follows, and the practical performance of the UHRAEM should be judged by totally evaluating them.1) Ultrahigh resolution to resolve ultrafine structure by atomic-level observation.2) Nanometer probe analysis to analyse the constituent elements in nm-areas of the specimen.3) Better performance of x-ray detection for EDS analysis, that is, higher take-off angle and larger detection solid angle.4) Higher specimen tilting angle to adjust the specimen orientation.To attain these requirements simultaneously, the objective lens polepiece must have smaller spherical and chromatic aberration coefficients and must keep enough open space around the specimen holder in it.

Amorphous Films at Metal/Ceramic Interfaces

2003 ◽  
Vol 94 (3) ◽  
pp. 272-276 ◽  
Author(s):  
Amir Avishai ◽  
Christina Scheu ◽  
Wayne D. Kaplan
Keyword(s):  
Amorphous Films ◽  
Metal Ceramic ◽  
Ceramic Interfaces

Interface Electronic And Magnetic Structures Of Layered Fe In Contact With MgO

1991 ◽  
Vol 238 ◽  
Author(s):  
Young Keun Kim ◽  
Michael E. McHenry ◽  
Manuel P. Oliveria ◽  
Mark E. Eberhart
Keyword(s):  
First Principles ◽  
State Of The Art ◽  
Magnetic Moments ◽  
Magnetic Structures ◽  
Consistent Field ◽  
Structure Of Metal ◽  
Metal Ceramic ◽  
Layer Technique ◽  
Self Consistent Field ◽  
Ceramic Interfaces

ABSTRACTA model based on the state-of-the-art, first-principles layer Korringa-Kohn-Rostoker (LKKR) method has proven to be very effective in describing the electronic and magnetic structure of metal/ceramic interfaces. We have performed self-consistent field computations incorporating spin polarization both for Fe/MgO superlattice (bulk technique) and for MgO/Fe/MgO sandwich (layer technique) systems. Muffin-tin potentials were employed for both materials in our computations. Iron layer was embedded in MgO, the host material, to have a [110](100)Fe / [100](100)MgO contact configuration. A large enhancement of magnetic moments has been found at the interface.

Comparison of results obtained by static 3- and 4-point bending and flexural vibration tests on solid wood, MDF, and 5-plywood

Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 941-948 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Medium Density Fiberboard ◽  
Flexural Vibration ◽  
Solid Wood ◽  
Bending Tests ◽  
Four Point Bending ◽  
Flexural Vibration Test ◽  
The Difference ◽  
Vibration Tests

Abstract The flexural Young’s modulus of western hemlock, medium-density fiberboard, and 5-plywood (made of lauan) has been determined by conducting three- and four-point bending tests with various span lengths and by flexural vibration test. The Young’s modulus was significantly influenced by the deflection measurement method. In particular, the Young’s modulus was not reliable based on the difference between the deflections at two specific points in the specimen, although this test is standardized according to ISO 3349-1975 and JIS Z2101-2009.

Long-Term Reliability Assessment of Bioceramics for Artificial Joints Using Microdamage Monitoring by AE

2006 ◽  
Vol 309-311 ◽  
pp. 1191-1194
Author(s):  
Shuichi Wakayama ◽  
Teppei Kawakami ◽  
Junji Ikeda
Keyword(s):  
Critical Stress ◽  
Reliability Assessment ◽  
Physiological Saline ◽  
Bending Test ◽  
Unstable Fracture ◽  
Artificial Joints ◽  
Bending Tests ◽  
Four Point Bending

Microfracture process during bending tests of alumina ceramics used for artificial joints was evaluated by acoustic emission (AE) technique. Four-point bending tests were carried out in air, refined water, physiological saline and simulated body fluid. AE behavior during bending test inhibited the rapid increasing point of AE events and energy prior to the final unstable fracture. It was understood that the bending stress at the increasing point corresponds to the critical stress for maincrack formation. The critical stress was affected by water in environments more strongly than fracture strength. Consequently, it was suggested that the characterization of maincrack formation is essential for the long-term reliability assessment of load-bearing bioceramics.

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