Search Results for photo spectrometry

Spark source mass spectrometry (SSMS) is an analytical technique used for determining the concentration of elements in a wide range of solid samples, including metals, semiconductors, ceramics, geological and biological materials, and air and water pollution samples. This article discusses the basic principles of spark source technique; SSMS instrumentation such as ion source, electric sector, and magnetic sector; sample preparation; and test procedures of SSMS. Some of the related techniques to SSMS are laser ionization mass spectrometry and laser-induced resonance ionization mass spectrometry. The ions produced in SSMS are detected by either the photometric method or electrical detection method and quantitatively measured by techniques such as internal standardization techniques, isotope dilution, multi element isotope dilution, and dry spike isotope dilution. The detected spark source spectrum contains all the elemental data of the tested sample. Finally, the article exemplifies the applications of SSMS.

This article provides information on the chemical characterization of surfaces by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). It describes the basic theory behind each of these techniques, the types of data produced from each, and some typical applications. The article explains the strengths of AES, XPS, and TOF-SIMS based on data obtained from the surface of a slightly corroded stainless steel sheet.

This article provides a detailed account of X-ray spectroscopy used for elemental identification and determination. It begins with an overview of the operating principles of X-ray fluorescence (XRF) spectrometer, as well as a comparison of the operating principles of wavelength-dispersive spectrometer (WDS) and energy-dispersive spectrometer (EDS). This is followed by a discussion on the mechanism and effects of X-ray radiation, X-ray emission, and X-ray absorption. The article then discusses components used, operation, and applications of WDS and EDS. Some of the factors and processes involved in sample preparation for XRF analysis are also included. The article further provides information on the practical procedure for and the applications of WDS and EDS qualitative and quantitative analyses.

This article provides a clear but nonexhaustive description of the general principle of atomic emission, with a particular focus on instrumentation, and summarizes the main characteristics of the inductively coupled plasma optical emission spectrometer technique. Basic atomic theory as well as the instrument characteristics and their influence on the instrument performances are presented. The advantages, drawbacks, and developments of this technique are discussed, and, finally, alternative techniques and examples of applications are provided.

This article introduces the fundamental concepts and the essential components of liquid chromatography (LC). It discusses the different modes of LC, such as liquid-solid chromatography, liquid-liquid chromatography, bonded-phase chromatograph, normal-phase chromatography, reversed-phase chromatography, ion-exchange chromatography, ion-pair chromatography, and size-exclusion chromatography. The article also includes a discussion on the qualitative and quantitative analyses and the applications of LC.

This article describes some of the common elemental composition analysis methods and explains the concept of referee and economy test methods in failure analysis. It discusses different types of microchemical analyses, including backscattered electron imaging, energy-dispersive spectrometry, and wavelength-dispersive spectrometry. The article concludes with information on specimen handling.

This article describes the analytical methods for analyzing surfaces for corrosion and corrosion inhibition processes as well as failure analysis based on surface structure and chemical identity and composition. The principles and applications of the surface-structure analysis techniques, namely, optical microscopy, scanning electron microscopy, scanning tunneling microscopy, and atomic force microscopy, are reviewed. The article discusses the principles and applications of chemical identity and composition analysis techniques. These techniques include the energy dispersive X-ray spectroscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy, ion scattering spectroscopy, reflectance Fourier transform infrared absorption spectroscopy, Raman and surface enhanced Raman spectroscopy, and extended X-ray absorption fine structure analysis.

This article is a compilation of terms and definitions related to materials characterization.

This article is a compilation of abbreviations, symbols, and tradenames for terms related to the properties, selection, processing, and applications of the most widely used nonmetallic engineering materials.

This article is a compilation of definitions of terms related to materials characterization techniques.

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) is an analytical technique for elemental determinations in the concentration range of major to trace based on the principles of atomic spectroscopy. This article provides a description of the basic atomic theory, and explains the analytical procedures and various interference effects of ICP, namely, spectral, vaporization-atomization, and ionization. It provides a detailed discussion on the principal components of an analytical ICP system, namely, the sample introduction system; ICP torch and argon gas supplies; radio-frequency generator and associated electronics; spectrometers, such as polychromators and monochromators; detection electronics and interface; and the system computer with appropriate hardware and software. The article also describes the uses of direct-current plasma, and provides examples of the applications of ICP-AES.

Ultraviolet/visible (UV/VIS) absorption spectroscopy is a powerful yet cost-effective tool that is widely used to identify organic compounds and to measure the concentration of principal and trace constituents in liquid, gas, and solid test samples. This article emphasizes the quantitative analysis of elements in metals and metal-bearing ores. The instrumentation required for such applications consists of a light source, a filter or wavelength selector, and some type of visual or automated sensing mechanism. The article examines common sensing options and provides helpful information on how to set up and run a variety of UV/VIS absorption tests.

Electron probe microanalysis (EPMA) makes it possible to combine structural and compositional analysis in one operation. This article describes the basic concepts of microanalysis and the processing of EPMA that involves the measurement of the characteristic X-rays emitted from a microscopic part of a solid specimen bombarded by a beam of accelerated electrons. It provides information on the various aspects of energy-dispersive spectrometry (EDS) and wavelength-dispersive spectrometry (WDS), and elucidates the qualitative analysis of the major constituents of EDS and WDS. The article includes information on the analog and digital compositional mapping of elemental distribution, and describes the strengths and weaknesses of WDS and EDS spectrometers in X-ray mapping. It also outlines the application of EPMA for solving various problems in materials science.

Scanning electron microscopy (SEM) has unique capabilities for analyzing fracture surfaces. This article discusses the basic principles and practice of SEM, with an emphasis on its applications in fractography. The topics include an introduction to SEM instrumentation, imaging and analytical capabilities, specimen preparation, and the interpretation of fracture features. SEM can be subdivided into four systems, namely, illuminating/imaging, information, display, and vacuum systems. The article also describes the major criteria and techniques of SEM specimen preparation, and the general features of ductile and brittle fracture modes.

This article introduces various techniques commonly used in the characterization of semiconductors, namely single-crystal, polycrystalline, amorphous, oxide, organic, and low-dimensional semiconductors and semiconductor devices. The discussion covers material classification, fabrication methods, sample preparation, bulk/elemental characterization methods, microstructural characterization methods, surface characterization methods, and electronic characterization methods.

Infrared (IR) spectra have been produced by transmission, that is, transmitting light through the sample, measuring the light intensity at the detector, and comparing it to the intensity obtained with no sample in the beam, all as a function of the infrared wavelength. This article discusses the sampling techniques and applications of IR spectra as well as the molecular structure information it can provide. The discussion begins with a description of the general principle of IR spectroscopy. This is followed by a section on commercial IR instruments. Sampling techniques and accessories necessary in obtaining the infrared spectrum of a material are then discussed. The article presents various techniques and methods involved in IR qualitative analysis and quantitative analysis. It ends with a few examples of the applications of IR spectroscopy.

Infrared (IR) spectroscopy is a useful technique for characterizing materials and providing information on the molecular structure, dynamics, and environment of a compound. This article provides the basic principles and instrumentation of IR spectroscopy. It discusses the sampling techniques of IR spectroscopy, namely, attenuated total reflectance spectroscopy, diffuse reflectance spectroscopy, infrared reflection-absorption spectroscopy, emission spectroscopy, and photoacoustic spectroscopy, and chromatographic techniques. Explaining the qualitative analysis of IR spectroscopy, the article provides information on spectral absorbance-subtraction, analysis of components in spectral matrix mixture, and determination of exact peak location of broad profiles. It discusses the quantitative analysis that mainly includes Beer's law for single compound in single wave number. The article also exemplifies the applications of IR spectroscopy.

This article discusses the installation of the most commonly used force-monitoring devices, namely, load cells and piezoelectric force sensors. It describes the purpose and operation of commonly used displacement sensors, such as linear variable differential transformers, proximity sensors, photoelectric sensors, and ultrasonic sensors. The article provides information on the sensors used for detecting tool breakages and flaws in parts, the measurement of material flow during sheet metal forming, and lubrication. It also describes the operating stages of machine vision systems used for automated quality-control purposes. The theory of eddy-current-based material properties evaluation is also discussed.