Search Results for X-ray diffractometer

X-ray diffraction (XRD) is the most extensively used method for identifying and characterizing various aspects of metals related to the arrangements and spacings of their atoms for bulk structural analysis. XRD techniques are also applicable to ceramics, geologic materials, and most inorganic chemical compounds. This article describes the operating principles and types of XRD analyses, along with information about the threshold sensitivity and precision, limitations, sample requirements, and capabilities of related techniques. The necessary instrumentation for XRD analyses include the Debye-Scherrer camera and the X-ray diffractometer. The article also describes the uses of XRD analyses, such as the identification of phases or compounds in metals and ceramics; detection of order and disorder transformation; determination of lattice parameters and changes in lattice parameters due to alloying and temperature effects; measurement of residual stresses; characterization of crystallite size and perfection; characterization of preferred orientations; and determination of single crystal orientations.

X-ray powder diffraction (XRPD) techniques are used to characterize samples in the form of loose powders or aggregates of finely divided material that readily diffract x-rays in specified patterns. This article provides an introduction to XRPD, beginning with a review of sensing devices, including pinhole/Laue cameras, Debye-Scherrer/Gandolfi cameras, Guinier cameras, glancing angle cameras, conventional diffractometers, thin film diffractometers, Guinier diffractometers, and micro diffractometers. The article then describes several quantitative measurement methods, such as lattice parameter, absorption diffraction, spiking, and direct comparison, explaining where each may be used. It also identifies potential sources of error in XRPD measurements.

X-ray powder diffraction (XRPD) techniques are used to characterize samples in the form of loose powders, aggregates of finely divided material or polycrystalline specimens. This article provides a detailed account of XRPD. It begins with a discussion on XRPD instrumentation and the techniques used to characterize samples. The article then describes the principles, advantages, and disadvantages of various types of powder diffractometers. A section on the Rietveld method of diffraction analysis is then presented. The article discusses various methods and procedures for qualifying and quantifying phase mixtures in powder samples. It provides information on typical sensitivity and experimental limits on precision of XRPD analysis and other systematic sources of errors that affect accuracy. Some of the factors pertinent to the estimation of crystallite size and defects are also presented. The article ends with a few application examples of XRPD.

This article discusses various concepts of micro x-ray diffraction (XRD) used for the examination of materials in situ. The discussion covers the principles, equipment used, sample preparation procedure, considerations for calibrating a detector, steps for performing data analysis, and applications and interpretation of micro-XRD.

Neutrons are a principal tool for the study of lattice vibrational spectra in materials. This article provides a detailed account of fission and spallation methods of neutron production that are capable of producing sufficient intensity to be useful in neutron scattering research. It describes the instrumentation required for, and advancements made in, neutron powder diffraction. The article further explains the texture and residual stress (macrostresses and microstresses) problems that are analyzed using the neutron powder diffraction method. It also outlines the single-crystal neutron diffraction technique, and provides examples of the applications of neutron diffraction.

This article provides a detailed account of the concepts of single-crystal x-ray diffraction (XRD). It begins with a historical review of XRD methods, followed by a description of the various factors involved in crystal symmetry. The article then focuses on the phase problem in x-ray structural analysis and validation of the structural model. Some of the factors to be considered for performing experimental procedure are provided. The article presents several examples of applications of single-crystal XRD. The following sections cover the crystallographic problem in terms of structural analysis, software programs for crystal structure solution and refinement, and visualization of crystal structures. The article ends with a discussion on various databases available for single-crystal XRD analysis.

The concept of surface integrity for grinding operations can be extended to encompass six different groups of key factors: visual, dimensional, residual stress, tribological, metallurgical, and others. This article discusses the importance of these factors in the performance and behavior of finishing methods in various manufactured parts. Special emphasis is given to residual stresses and their influence on the final mechanical properties of a manufactured part.

This article provides a useful guide for measuring residual macrostress on coatings. The most commonly used measurement methods are mechanical deflection, X-ray diffraction, and hole-drilling strain-gage. After a discussion on the origins of residual stress, the article describes the fundamental principles and presents examples of practical measurements for each method.