Search Publications

Displaying 1251 - 1275 of 1323

Accurate Texture Measurements on Thin Films Using a Powder X-Ray Diffractometer

June 1, 1999

Author(s)

Mark D. Vaudin

A fast and accurate method that uses a conventional powder x-ray diffractometer has been developed for measuring crystalline texture. A θ - 2θscan of a Bragg peak from the textured planes is collected and also a θ scan, or rocking curve, using the same

Analysis of Residual Stress State in Thermal Barrier Coatings

June 1, 1999

Author(s)

Tze-Jer Chuang, Lin-Sien H. Lum

To enhance thermal efficiency of a system in high temperature structural applications, thermal barrier coatings (TBC) are often applied on the metallic substrate to protect the component from deterioration while increasing the operating temperature of the

Estimation of Characteristic Parameters of a Grain-Bridging Model for Crack-Extension

June 1, 1999

Author(s)

Ralph Krause

An alternative method of analysis was developed to estimate characteristic parameters of a published grain-bridging model for crack-extension resistance (R-curve) and to enable estimations of standard deviations of the perameters, which determine to a

Grain Boundary Crack Growth in Interconnects With an Electric Current

June 1, 1999

Author(s)

C Y. Liu, S K. Lee, Tze J. Chuang

Failure of thin-film interconnects poses a great concern in semiconductor devices. Due to the high electric current density in interconnects, electromigration-induced atomic flux is recognized as an important failure mechanisms. For wide polycrystalline

Some Remarks on Improved Analysis for Flexural Creep with Application to Sialon Ceramics

June 1, 1999

Author(s)

Tze J. Chuang

An earlier paper co-authored by the present author contains a major assumption in the analytical method that not be valid in a general class of structural ceramics. A more-rigorous mathematical analysis without this assumption has been performed, and the

Bond Lengths in Strained Semiconductor Alloys

May 1, 1999

Author(s)

Joseph C. Woicik

The bond lengths in a series of strained, buried Ga1-xInxAs thin-alloy films grown coherently on GaAs(001) and InP(001) substrates have been determined by high-resolution extended x-ray absorption fine-structure and diffraction anomalous fine-structure

Reliability of Structural Parameters Determined from DAFS Data Using the Iterative Dispersion Integral Algorithm

May 1, 1999

Author(s)

J O. Cross, W Elam, Joseph Woicik, L B. Sorensen

The iterative Kramers-Kronig (IKK) dipersion integral lgorithm is commonly used to isolate the complex resonant scattering amplitude δf= f' + if from measured diffraction anomalous fine structure (DAFS) intensity data, where the imaginary part f is

Tensile Creep and Rupture of Silicon Nitride

May 1, 1999

Author(s)

Ralph Krause, William E. Luecke, J French, B Hockey, Sheldon M. Wiederhorn

We have characterized the tensile creep, rupture lifetime, and cavitation behavior of a commercial, gas-pressure-sintered silicon nitride in the temperature range 1150 to 1400 C and stress range 70 to 400 MPa. Individual creep curves generally show primary

The Local Structure of Ferroelectric Pb 1-x Ge x Te

May 1, 1999

Author(s)

Bruce D. Ravel, Eric J. Cockayne, K M. Rabe

The narrow band-gap semiconductor Pb_{1-x}Ge_xTe has a low-temperature ferroelectric rhombohedral phase whose average structure is a distorted rock salt structure. We have measured the Extended X-ray-Absorption Fine-Structure spectra of Pb_{1-x}Ge_xTe with

Generation of Different UHMWPE Particle Shape by Wear Through Surface Texturing

April 1, 1999

Author(s)

H. W. Fang, M C. Shen, U Cho, John A. Tesk, A Christou, Stephen M. Hsu

Ultra-high molecular weight polyethylene (UHMWPE) wear particles in replaced joints have been linked to biochemical reactions that eventually lead to loosening of prosthesis. Several studies have shown that UHMWPE produces a wide range of particle sizes

Effect of Electrode Layer on the Polydomain Structure of Epitaxial PbZr 0.2 Ti 0.8 O 3 Thin Films

March 15, 1999

Author(s)

S P. Alpay, V Nagarajan, Leonid A. Bendersky, Mark D. Vaudin, S Aggarwal, R Ramesh, Alexander L. Roytburd

PbZr 0.2Ti 0.8O 3(PZT) thin films with and without La 0.5Sr 0.5CoO 3(LSCO) electrodes were grown epitaxially on (001) SrTiO 3 (STO) at 650 C by pulsed laser deposition. The domain structure of the 400 nm thick PZT films with different electrode layer

Local Environments of Three Forms of Ba 2 Ycu 3 O 6+x

March 12, 1999

Author(s)

Winnie K. Wong-Ng, M Melamud, Lawrence H. Bennett

The Wigner-Seitz local atomic cell construction procedure, provides a topological means for comparing series of related structures in terms of the number and type of nearest neighbors. We used this construction to further our understanding of the chemical

Crystal Structures and Reference Powder Patterns of BaR 2 ZnO 5 (R=La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, and Tm)

March 1, 1999

Author(s)

James A. Kaduk, Winnie Wong-Ng, W Greenwood, J Dillingham, B H. Toby

Reference x-ray patterns and the crystal structure of the lanthanide compounds, BaR 2ZnO 5, in which R=La, Nd, Sm, Eu, Gd, Dy, Ho, Y, and Er, were studied by x-ray Rietveld refinement technique. A structural trend was confirmed for this series of compounds

Microstructural Changes in YSZ Deposits During Annealing

March 1, 1999

Author(s)

Andrew J. Allen, J Ilavsky, Gabrielle G. Long, Jay S. Wallace, C C. Berndt, H Herman

Various methods have been applied to the microstructural characterization of thermally-sprayed depostis. However, coexisting anisotropic distributions of intra-splat cracks and interlamellar pores, and the broad size range of rounded globular pores, have

The Role of Feedstock Particle Size on the Microstructural Behavior of Plasma-Sprayed YSZ Deposits During Annealing

March 1, 1999

Author(s)

H Boukari, Andrew J. Allen, Gabrielle G. Long, J Ilavsky, Jay S. Wallace, C C. Berndt, H Herman

We have studied the microstructure of thick plasma-sprayed yttrium-stabilized zirconia deposits fabricated from different initial feedstock particle size (32, 47, 56 and 88) m in a series of mulitiple and Porod small-angle neutron scattering experiments

VAMAS Technical Working Area #3

March 1, 1999

Author(s)

George D. Quinn, E F. Begley

Technical Working Area #3, Ceramics of the Versailles Advanced Materials and Standards (VAMAS) project has conducted 12 projects and 12,000 experiments over 12 years. This website explains TWA3, and lists the key accomplishments and publications from the

Barium Hollandite-Type Compounds Ba x Fe 2x Ti 8-2x O 16 with x= 1.143 and 1.333

February 23, 1999

Author(s)

J. M. Loezos, Terrell A. Vanderah, A R. Drews

Experimental X-ray powder diffraction patterns and refined unit cell parameters for two barium hollandite-type compounds. Ba xFe 2xTi 8-2xO 16, with x = 1.143 and 1.333, are reported here. Compared to the tetragonal parent structure, both compounds exhibit

Ceramic Measures: News of the Ceramic Processing Characterization Consortium, February 1999

February 1, 1999

Author(s)

S Jahanmir

Newsletter, Ceramic Measures: News of the Ceramic Processing Characterization Consortium, February 1999, Vol. 3, Issue 1.

The Use of Cyclic Phosphazene Additives to Enhance the Performance of the Head/Disk Interface

January 29, 1999

Author(s)

H J. Kang, Q Zhao, F E. Talke, D J. Perettie, B M. DeKoven, T A. Morgan, Daniel A. Fischer, Stephen M. Hsu, C S. Bhatia

Phase separation of phosphazene additives in perfluoropolyalkylether (PFPAE) lubricants is investigated as a function of additive concentration and lubricant layer thickness. The tribological behavior of various phosphazene additive/lubricant mixtures is

Wear Induced Molecular Orientation in Ultra High Molecular Weight Polyethylene (UHMWPE) Measured by Soft X-Ray Adsorption

January 29, 1999

Author(s)

Daniel A. Fischer, S Sambasivan, M C. Shen, Stephen M. Hsu

Molecular orientation in ultra high molecular weight polyethylene (UHMWPE) when it is subjected to wear is important in understanding the basic wear processes for this material. Current methods of inferring or deducing orientation information for UHMWPE

Effects of Wear Motion on Ultra High Molecular Weight Polyethylene (HMWPE) Molecular Orientation

January 28, 1999

Author(s)

S Sambasivan, Daniel A. Fischer, M C. Shen, Stephen M. Hsu

In a human hip joint, the motion is complex and consists of flexion/extension, abduction, and adduction. Laboratory studies have shown that these motions increase wear significantly. The aim of this study is to measure the change in molecular orientation

Simple Empirical Cluster Expansion Hamiltonians for Modeling Cation Order-Disorder in A(B'^d1/3B2/3)O3 Perovskites Such as Pb(Mg1/3Nb2/3)O3

January 15, 1999

Author(s)

Benjamin P. Burton

Brute force exploration of the simple cubic effective cluster interaction space indicates that linear triplet interaction is both necessary and sufficient to stablizde a P3ml ground state, and a P3ml Fm - 3m transition at 4.5183

Effect of Film Composition on the Orientation of (Ba,Sr)TiO 3 Grains in (Ba,Sr) y TiO 2+y Thin Films

January 12, 1999

Author(s)

Debra L. Kaiser, Mark D. Vaudin, L D. Rotter, John E. Bonevich, J T. Armstrong

(Ba,Sr) yTiO 2+y thin films with 0.34 {1-xSr xTiO 3 (x {aproximately equal to} 0.06) and an amorphous phase. The orientation of the tetragonal Ba 1-xSr xTiO 3 grains (pure a axis, pure c axis, or a mix of the two) was found to be strongly dependent upon

Assessment of Particle Size Measurement Techniques and Procedures: I. Identification and Characterization of a Model Powder System

January 1, 1999

Author(s)

Ajitkumar Jillavenkatesa, Vincent A. Hackley, G Y. Onoda

Particle size distribution of a powder system has been observed to be dependent upon the instrument and technique used for analysis. Often, different instruments based upon the same fundamental principle give different results for the same powder. This

Ceramic Whisker Reinforcement of Dental Resin Composites

January 1, 1999

Author(s)

H H. Xu, T A. Martin, Joseph M. Antonucci, F Eichmiller