Non-destructive Analytical Tool Research Articles

Morphotropic domain structures and phase transitions in relaxor-based piezo-/ferroelectric (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 single crystals

The domain structures and phase transitions of relaxor-based piezo-/ferroelectric (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 [PMNT] single crystals, grown from high temperature solutions, have been analyzed by polarized light microscopy using an optical crystallographic approach. The substitution of Ti4+ ions for the B-site complex (Mg1/3Nb2/3)4+ ions in the relaxor PMN results in a long-range symmetry breaking, as revealed by the formation of birefringent macrodomains. The domain structures of the PMNT80/20 crystals indicate a primitive trigonal symmetry at room temperature with a weak birefringence. PMNT crystals with 50% Ti show tetragonal domain structures, reflecting the symmetry of PbTiO3. Single crystals of PMNT65/35 exhibit complex morphotropic domain structures, which are composed of both the trigonal and the tetragonal phase intimately mixed together. The domain structures, the sequence and temperature of phase transitions have been interpreted in relation to the morphotropic phase boundary behavior of the PMN-PT system. It is shown that in situ analysis of domain structures and phase transitions can be used as a nondestructive analytical tool for evaluating the local morphotropic composition and the properties, which sensitively depend upon the individual domains and the Ti4+ concentration. The analysis of morphotropic domain structures and phase transitions provides a better understanding of the microscopic mechanisms of the enhanced piezoelectric properties recently disclosed in PMNT and other relaxor-based piezocrystals.

High frequency scanning acoustic microscopy: a novel non-destructive surface analytical tool for assessment of coating-specific elastic moduli and tomographic study of subsurface defects

Acoustic microscopy has been used as a non-destructive analytical tool for characterising various coating/substrate systems. A novel high-frequency instrument especially developed for Materials Science engineers is presented, and its technical and theoretical specifications are described. In the acoustic signature mode (quantitative mode), local elastic moduli are extracted. The numerical results are compared to those obtained by depth-sensing indentation. In the imaging mode (qualitative mode), this technique allows without etching a clear distinction of the surface grain structure from the stress gradients at grain boundaries and from the mechanical anisotropy of differently oriented grains. Moreover, tomographic imaging of subsurface flaws is shown. Hidden scratch-induced cracks are revealed by comparison with standard metallographic microscope observations.

Nondestructive Analytical Tools for Characterization of Thin Titanium Silicide Films Prepared by Conventional and Direct Step Silicidation with Enhanced Transition

Nondestructive analytical tools (e.g., spectral ellipsometry, thermal wave analysis, atomic force analysis, etc.) have been used to characterize thin titanium silicide films. The parameters of silicide films (layer thickness, uniformity, phase transition, etc.) obtained using nondestructive tools are compared using traditional analytical techniques including four‐point probe, X‐ray diffraction, and cross‐sectional transmission electron microscopy. Properties of thin films prepared by an advanced one‐step annealing process featured by direct step silicidation with enhanced transition has been compared with that obtained from a conventional two‐step annealing process. This process produces thin films with improved surface roughness without causing the agglomeration and uncompleted phase transition failure. Optical properties such as refractive indexes, reflectivity, and dielectric constants of the thin films as obtained from spectroscopic ellipsometer measurements are reported in the wavelength range 0.25‐0.90 μm. © 1999 The Electrochemical Society. All rights reserved.

Characterisation of TiN and carbon-doped chromium thin film coatings by acoustic microscopy

Acoustic microscopy has been used as a non-destructive analytical tool for characterising bulk materials (fused silica, steel) and thin films (carbon-doped chromium, titanium nitride).In the acoustic signature mode (quantitative mode), elastic parameters such as Young's modulus and Poisson ratio local modulus are extracted. In the case of coatings, the variation of wave velocity as a function of operating frequencies (30 MHz–2 GHz) is modelled by an open system whose parameters (longitudinal and transversal velocity of the coating and the substrate, thickness of the coating) are adjusted. The numerical results are compared to those obtained by impact excitation and to depth-sensing instrumented indentation.In the imaging mode (qualitative mode), this technique allows a clear distinction of the surface grain structure from the stress gradients at grain boundaries and from the mechanical anisotropy of differently oriented grains, without etching. Moreover, tomographic imaging of subsurface flaws is shown. For example, hidden scratch-induced cracks are revealed by comparison with standard metallographic microscope observations.

Fourier transform Raman spectroscopy: evaluation as a non-destructive technique for studying the degradation of human hair from archaeological and forensic environments

Fourier transform (FT) Raman spectroscopy was evaluated as a non-destructive analytical tool for assessing the degradative state of archaeological and forensic hair samples. This work follows the successful application of FT-Raman spectroscopy to studies of both modern hair and ancient keratotic biopolymers, such as mummified skin. Fourteen samples of terminal scalp hair from 13 disparate depositional environments were analysed for evidence of structural alteration. Degradative change was evidenced by alteration to the amide I and III modes near 1651 and 1128 cm−1, respectively, and loss of definition to the (CC) skeletal backbone and the impact of environmental contaminants was noted. Copyright © 1999 John Wiley & Sons, Ltd.

A Case Study of Employing Spectroscopic Tools for Monitoring Reactions in the Developmental Stage of a Combinatorial Chemistry Library

Organic synthesis on solid-phase resins requires new applications of nondestructive analytical tools to monitor the progress of reactions. Herein we describe our novel approach to validate a five-step reaction sequence on resin. We have developed a protocol list that allows us to follow reactions step-by-step using different analytical procedures in the order of increasing experiment time. Results from these various techniques for each reaction step are contrasted and compared. The key to achieve definitive analytical data for the entire reaction sequence is the combined application of more than one analytical technique.

Surfactants in latex films; interactions with latex components and quantitative analysis using ATR and step-scan PAS FT-IR spectroscopy

This paper focuses on the behavior of low-molecular-weight surfactant molecules in latex films and how their distribution may influence coalescence and other film properties. Using recently developed spectroscopic non-destructive analytical tools, quantitative assessments concerning surfactant distribution and their interactions with latex components will be presented. Particular efforts will be given to recent developments in quantitative analysis using attenuated total reflectance (ATR) and step-scan photoacoustic (S 2-PAS) Fourier transform infrared (FT-IR) spectroscopy.

BSCAT: Code for simulation and for analysis of the RBS/NRA spectra

A beam of charged particles as a tool for non-destructive analysis of the structure and elemental composition of thin-surface layers is frequently used in material investigations. Nuclear methods such as RBS or NRA techniques have a good depth resolution and sufficient mass sensitivity. Many computer programs exist, like the RUMP [see L.R. Doolitle, Nucl. Instr. and Meth. B 9 (1985) 344] or DVBS [see V. Boháč and D.M. Shirokov, Nucl. Instr. and Meth. B 84 (1994) 497] codes, for simulation and for analysis of experimental results collected in measurements with beams of charged particles. A new computer code, called BSCAT (BackSCATtering), was created at the Institute of Nuclear Physics to analyze experimental spectra and to simulate new experiments. The BSCAT code, written in FORTRAN-77 and partially in C, can work on IBM personal computers or on larger computers such as CONVEX machines. As input for the program both Rutherford and non-Rutherford cross sections can be used and the stopping power function can be calculated by the Ziegler or the Montenegro formula. The program was used in the analysis of complex spectra of backscattered particles. Among other applications the BSCAT code was used for analysis of the spectrum of 2100 keV protons bombarding a thin carbon foil created by the IBAD technique on the surface of a Si {111} single crystal [ 12C(p, p) 12C and 28Si(p, p) 28Si resonance].

Computed tomography as a tool for non-destructive analysis of flow patterns in macroporous clay soils : A. W. J. Heijs, J. De Lange, J. F. T. Schoute & J. Bouma, Geoderma, 64(3–4), 1995, pp 183–196

Computed tomography as a tool for non-destructive analysis of flow patterns in macroporous clay soils : A. W. J. Heijs, J. De Lange, J. F. T. Schoute & J. Bouma, Geoderma, 64(3–4), 1995, pp 183–196

New approach to assess the cholesterol distribution in the eye lens: confocal Raman microspectroscopy and filipin cytochemistry.

Confocal Raman microspectroscopy (CRM) is a non-invasive, non-destructive, and sensitive analytical tool for the study of some aspects of the molecular organization of cells and tissues with high spatial resolution. Filipin, a polyene antibiotic, specifically binds to cholesterol, and its molecular structure predicts it to be Raman-active. The aim of the present study was to assess the potentialities of a combined CRM-filipin approach to study the distribution of cholesterol in the human eye lens. Paraformaldehyde-fixed human lenses were sliced (0.7 mm), incubated with filipin, and analyzed by CRM. Filipin proved to give a specific Raman signal at 1586 cm-1, hardly interfering with signals from lens proteins. The CRM-filipin approach proved to be extremely sensitive, allowing detection of cholesterol in the femtogram range. It has an excellent spatial resolution (0.2-0.5 micron 3) when using point measurements. Due to the intrinsic anisotropy of membranes in the eye lens and therefore of the cholesterol distribution, a line-scan approach has to be adopted when fiber-to-fiber changes in cholesterol are of interest. The distribution of filipin along the optical axis of four human eye lenses was compared with data from the literature. The combined CRM-filipin approach is a highly specific and sensitive method for the study of cholesterol within cells and tissues. The spatial resolution is high and can be adapted to the desired discriminative power. The gross distribution of filipin along the optical axis obtained in this study is similar to that found in biochemical studies.

Computed tomography as a tool for non-destructive analysis of flow patterns in macroporous clay soils

This article presents a review of applications of computed tomography (CT) in soil science and petroleum engineering. We discuss the use of CT images to obtain quantitative expressions for soil structure. We elucidate this approach with a case study of an infiltration experiment in an undisturbed clay soil. The clay sample was scanned in initially dry condition and after infiltration of water with a contrast agent. The sample was scanned in 150 adjacent slices in both cases. The three-dimensional macropore network was determined from the 150 CT images scanned before infiltration. The water distribution in the soil was determined from the CT images after completion of the infiltration experiment. The three-dimensional water content distribution in the three-dimensional macropore network was quantified and visualized by matching the dry and wet images. The three-dimensional water content distribution in the matrix was also quantified and visualized.

Depth profiling of porous silicon layers by attenuated total reflection spectroscopy

Attenuated total reflection spectroscopy is presented as a non-destructive analytical tool to investigate porous silicon layers. It is shown how depth-dependent information on the chemical composition of the layers can be obtained by performing reflectance measurements at various angles of incidence and doing careful parameter fits in suitable models for the concentration of impurities such as oxygen and hydrogen. Results for samples treated by laser radiation during etching are shown.

Chemical composition of porous silicon layers studied by IR spectroscopy

IR spectroscopy is presented as a non-destructive analytical tool to determine the chemical composition of porous silicon. Model spectra — based on Si-O, Si-H, O-Si-H and Si-Si vibrations and taking into account the topological effects due to the porous structure — are adjusted to measured infrared reflectance spectra by varying the relevant parameters. The obtained information on the hydrogen and oxygen concentration is compared to the photoluminescence behaviour of samples taken “as formed” as well as for thermally and anodically oxidized samples.

Magnetic Resonance Imaging: A Nondestructive Analytical Tool for Developmental Physiology

Magnetic Resonance Imaging: A Nondestructive Analytical Tool for Developmental Physiology

Laser Raman spectroscopy and its applications — especially in structural phase transitions

The usefulness of Raman spectroscopy as a powerful non-contact, nondestructive analytical tool has been well-demonstrated. A bird’s eye-view of various techniques used for the study of various types of structural phase transitions is given. A few modern applications of laser Raman spectroscopic studies have been mentioned. Thermal variations near critical transition region in the position, halfwidths, intensities and shapes of few thermo-sensitive bands in a few organic and inorganic salts and complexes have been used to deduce the critical exponents β and the activation energyU for orientational disorder of NCS− ions and CH3NH3 type groups.

Evaluation of a microcomputed tomography system to study trabecular bone structure

A new microcomputed tomography (micro-CT) system and thresholding procedure was evaluated as a tool for nondestructive analysis of trabecular bone. Images of 6-mm trabecular bone cubes acquired from the micro-CT system were compared with optical images of corresponding histologic sections to determine the accuracy of representation. The stereologic measures of bone volume fraction (PP) and trabecular plate density (PL) were used to quantify the comparisons. The results showed that the micro-CT measures of PP were not significantly different from those measured from histologic sections and therefore were very accurate. Measures of PL were different by approximately 14%, which translated into discrepancies in trabecular plate thicknesses of about 19 microns. This difference was significantly correlated to the microstructural characteristics of the specific specimen scanned. The precision of both measurements was excellent.

Variable angle spectroscopic ellipsometry: A non-destructive characterization technique for ultrathin and multilayer materials

In the most commonly used form of ellipsometry, a monochromatic collimated linearly polarized light beam is directed at an angle ϕ to the normal of a sample under study. The specularly reflected beam is, in general, elloptically polarized, and the state of polarization is analyzed using a second polarizer and photodetector. A rotating analyzer automated spectroscopic ellipsometer has been constructed in our laboratory. The angle of incidence can be set over a wide range of angles, with a precision and repeatibility of ±0.01°. A computer controls the monochromator, the azimuth of a stepper-motor-driven polarizer, a shutter, and the digitization of the detector signal. There are several other schemes used for acquiring ellipsometric data, and these are discussed in several sources. The purpose of this short review is to show how variable angle of incidence spectroscopic ellipsometry can be used as a powerful non-destructive tool for analysis of surfaces and multilayer films.

Monitoring Aerosol Elemental Composition in Particle Size Fractions in Case of Long-Range Transport

Collection of atmospheric samples was performed at Malta, a semi-remote environment in the Mediterranean, in case of long-range transport studies of pollutants and natural substances, Using PIXE as a non-destructive trace-element analytical tool, the elemental composition of these samples was determined. Atmospheric concentrations obtained in this study were of one magnitude higher than those observed over the open North Atlantic in purely marine air. For most of the anomalously enriched elements in the Mediterranean aerosol, the high concentrations can be explained by long-range transport.

A New Analytical Method and Its Application to Cylinder Seals

Material analysis is a basic task of archaeometry, but it is problematic in many ways: the analysis should be representative but should not destroy or damage the object: the analysis should be rapid and inexpensive in order to enable the study of large quantities of objects for statistical evaluation. Analyses based upon small subsamples tend to give random results, i.e. results not representative for the entire specimen, but analyses of the entire body should be truly non-destructive. EDS-XFA (energy dispersive X-ray fluorescence analysis) is one of the few non-destructive analytical tools giving chemical information on the average composition of a surface. Nearly 90% of all natural chemical elements can be detected provided they are present as major or minor constituents. Like all instrumental techniques, EDS-XFA is based upon a comparison of unknown samples with standards of known composition (for details see Bertin, 1978); quantitative analysis is possible when surface conditions (size, morphology, texture, etc.) of unknowns and standards are identical. Regarding archaeological objects, the sample surface should not be treated, smoothed or flattened, but has to be left in its original morphology (which varies from specimen to specimen) and this may influence the analytical results. These are therefore considered to be qualitative and are essentially used to establish groups of similar chemical composition (Fig. 1). This chemical classification, when applied to cylinder seals, is closely associated with mineral/rock species since a clear interdependence exists between mineral species and their composition. The mineralogical classification, however, is, by tradition, based upon physical properties of minerals like optics, hardness, etc., and not primarily on their chemistry.

Resonance Raman spectroscopy as an analytical probe for biological chromophores: Spectra of four Cu-etioporphyrins

Summary Resonance Raman spectra have been obtained for the position isomers Cu-etioporphyrins I, II, III, and IV, as solids dispersed in KBr matrices. The spectra of the four molecules differ markedly in the 650–850 cm −1 region, enabling the substances to be distinguished. The potential of resonance Raman spectroscopy as a sensitive and non-destructive analytical tool is illustrated.