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Displaying 1151 - 1175 of 1721

Fracture Toughness of Toughened Silicon Nitride by ASTM C 1421

June 1, 2003
Author(s)
George D. Quinn, J Swab, M J. Motyka
The fracture toughness of a commercial sintered reaction-bonded silicon nitride was measured by the three complementary test methods in ASTM C 1421. Precracks ranged from tiny artificial flaws introduced by Knoop indentation to millimeter long precracks in

Monitoring Polymer/Clay Nanocomposites Compounding Using a Dielectric Slit Die

May 30, 2003
Author(s)
Anthony J. Bur, S C. Roth, M M. McBrearty
A new in-line process monitoring instrument, a dielectric slit die, was used to examine compounding of polymer/clay nanocomposites. It is a multi-purpose sensing device for measuring polymer dielectric, rheological and optical properties during extrusion

Blazing a Trail

May 1, 2003
Author(s)
Peter K. Schenck, Debra L. Kaiser
In this paper we discuss the application of pulsed laser deposition (PLD) to combinatorial materials research on inorganic thin films. The modifications to an existing PLD apparatus converting it to a dual beam dual target PLD system for the production of

Comprehensive Microstructural Characterization and Predictive Property Modeling of Plasma-Sprayed Zirconia Coatings

May 1, 2003
Author(s)
A Kulkarni, Z G. Wang, T Nakamura, S Sampath, A N. Goland, H Herman, Andrew J. Allen, J Ilavsky, Gabrielle G. Long, J Frahm, R W. Steinbrech
Quantitative microstructure characterization to better understand processing-microstructure-property correlations is of considerable interest in plasma sprayed coating research. This paper quantifies, by means of small-angle neutron scattering (SANS) data

Comprehensive Microstructural Characterization and Predictive Property Modelling of Plasma-Sprayed Zirconia Coatings

May 1, 2003
Author(s)
A Kulkarni, Z G. Wang, T Nakamura, S Sampath, A N. Goland, Gabrielle G. Long, H Herman, J. Allen, J Ilavsky, G J. Long, J Frahm, R W. Steinbrech
hieving control of the microstructure of plasma-sprayed thermal-barrier coating (TBC) systems offers an opportunity to tailor coating properties to demanding applications. Accomplishing this requires a fundamental understanding of the correlations between

Near the Static Fatigue Limit in Glass

May 1, 2003
Author(s)
Sheldon M. Wiederhorn, A Dretzke, J Rodel
The atomic force microscope is used to explore the nature of fracture surfaces in soda lime silicate glass formed near or below the apparent crack growth threshold. Conventional theory suggests that cracks in glass will blunt when subjected to stresses

A Model System for Interfacial Reactions in LTCC Materials

April 1, 2003
Author(s)
Lawrence P. Cook, Winnie K. Wong-Ng, Peter K. Schenck, Mark D. Vaudin, J Suh
Over the past decade, ceramic packaging materials have continued to increase in both chemical and structural complexity. At processing temperatures of 800 C to 900 C, the possibilities for interactions at interfaces between dissimilar materials are

A New Octahedral Tilt System in the Perovskite Phase Ca 3 Nb 2 O 8

April 1, 2003
Author(s)
L M. Cranswick, W G. Mumme, I E. Grey, Robert S. Roth, P Bordet
The perovskite-related phase Ca 3Nb 2O 8, when grown as single crystals from a calcium vanadate flux, incorporates a smallamount of vanadium from the flux to form the composition Ca 3Nb 2-xV xO 8 with x = 0.025 . The crystals have pseudo-cubicsymmetry with

Flux Pinning and Properties of Solid-Solution (Y,Nd) 1+x Ba 2-x Cu 3 O 7-d Superconductors

April 1, 2003
Author(s)
T J. Haugan, M E. Fowler, J C. Tolliver, Paul N. Barnes, Winnie K. Wong-Ng, Lawrence P. Cook
The effect of chemical composition variations on the flux pinning and physical properties of (Y,Nd)1+xBa2-xCu3O7-d superconductors was studied in powders processed by solid-state reaction and equilibrated in air at 910 C. An extended region of single-phase

High-Accuracy Determination of the Dependence of the PhotoluminescenceEmission Energy on Alloy Composition in Al x Ga 1-x As Films

April 1, 2003
Author(s)
Lawrence H. Robins, J T. Armstrong, Ryna B. Marinenko, Albert J. Paul, J G. Pellegrino, Kristine A. Bertness
In an effort to improve the accuracy of photoluminescence (PL)spectroscopy as a composition (Al mole fraction) measurement method forthe Al xGa 1-xAs alloy system, the PL peak emission energy,E PL,peak, was measured at room temperature for a set of MBE

Singular Grain Boundaries in Alumina and Their Roughening Transition

April 1, 2003
Author(s)
C W. Park, D C. Yoon, J Blendell, C A. Handwerker
The shapes and structures of grain boundaries formed between the basal (0001) surface of large alumina grains and randomly oriented small alumina grains are shown to depend on the additions of SiO 2, CaO, and MgO. If a sapphire crystal is sintered at 1620

Asymptotic Behavior of a Strain Percolation Model for a Deforming Metal

March 1, 2003
Author(s)
Y Shim, Lyle E. Levine, R M. Thomson, D E. Kramer
In this paper, we present a recent advance in theoretical understanding of a deforming metal, using a strain percolation model which possibly explains spasmodic, fine slip line burst events occurring in the metal. The model addresses how the additional

Cracking and the Indentation Size Effect for Knoop Hardness of Glasses

March 1, 2003
Author(s)
George D. Quinn, P Green, K Xu
The Knoop Hardness of five glasses as measured over a wide range of indentation loads. Hardness decreased with increasing load in accordance with the classic indentation size effect (ISE). At moderate loads, cracking dramatically altered the indentation
Displaying 1151 - 1175 of 1721