Characterization (materials science)

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The characterization technique optical microscopy showing the micron scale dendritic microstructure of a bronze alloy Glockenbronze.jpg
The characterization technique optical microscopy showing the micron scale dendritic microstructure of a bronze alloy

Characterization, when used in materials science, refers to the broad and general process by which a material's structure and properties are probed and measured. It is a fundamental process in the field of materials science, without which no scientific understanding of engineering materials could be ascertained. [1] [2] The scope of the term often differs; some definitions limit the term's use to techniques which study the microscopic structure and properties of materials, [2] while others use the term to refer to any materials analysis process including macroscopic techniques such as mechanical testing, thermal analysis and density calculation. [3] The scale of the structures observed in materials characterization ranges from angstroms, such as in the imaging of individual atoms and chemical bonds, up to centimeters, such as in the imaging of coarse grain structures in metals.

Contents

While many characterization techniques have been practiced for centuries, such as basic optical microscopy, new techniques and methodologies are constantly emerging. In particular the advent of the electron microscope and secondary ion mass spectrometry in the 20th century has revolutionized the field, allowing the imaging and analysis of structures and compositions on much smaller scales than was previously possible, leading to a huge increase in the level of understanding as to why different materials show different properties and behaviors. [4] More recently, atomic force microscopy has further increased the maximum possible resolution for analysis of certain samples in the last 30 years. [5]

Microscopy

Optical microscopy image of aluminium Aluminium Microstructure.jpg
Optical microscopy image of aluminium
Image of a graphite surface at an atomic level obtained by an STM Graphite ambient STM.jpg
Image of a graphite surface at an atomic level obtained by an STM

Microscopy is a category of characterization techniques which probe and map the surface and sub-surface structure of a material. These techniques can use photons, electrons, ions or physical cantilever probes to gather data about a sample's structure on a range of length scales. Some common examples of microscopy techniques include:

Spectroscopy

Spectroscopy is a category of characterization techniques which use a range of principles to reveal the chemical composition, composition variation, crystal structure and photoelectric properties of materials. Some common examples of spectroscopy techniques include:

Optical radiation

X-ray

First X-ray diffraction view of Martian soil - CheMin analysis reveals feldspar, pyroxenes, olivine and more (Curiosity rover at "Rocknest", October 17, 2012). PIA16217-MarsCuriosityRover-1stXRayView-20121017.jpg
First X-ray diffraction view of Martian soil - CheMin analysis reveals feldspar, pyroxenes, olivine and more (Curiosity rover at "Rocknest", October 17, 2012).
X-ray powder diffraction of Y2Cu2O5 and Rietveld refinement with two phases, showing 1% of yttrium oxide impurity (red tickers) XRD+Rietveld-Fit-Y2Cu2O5.png
X-ray powder diffraction of Y2Cu2O5 and Rietveld refinement with two phases, showing 1% of yttrium oxide impurity (red tickers)

Mass spectrometry

Nuclear spectroscopy

PAC probing the local structure by using radioactive nuclei. From the pattern, electric field gradients are obtained that resolve the structure around the radioactive atom, in order to study phase transitions, defects, diffusion. Complexpacspectrum.png
PAC probing the local structure by using radioactive nuclei. From the pattern, electric field gradients are obtained that resolve the structure around the radioactive atom, in order to study phase transitions, defects, diffusion.

Other

Macroscopic testing

A huge range of techniques are used to characterize various macroscopic properties of materials, including:

(a) effective refractive indexes and (b) absorption coefficients of integrated circuits obtained via terahertz spectroscopy (a) effective refractive indexes and (b) absorption coefficients of the electronic chips.jpg
(a) effective refractive indexes and (b) absorption coefficients of integrated circuits obtained via terahertz spectroscopy

See also

Related Research Articles

<span class="mw-page-title-main">Analytical chemistry</span> Study of the separation, identification, and quantification of the chemical components of materials

Analytical chemistry studies and uses instruments and methods to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes. Qualitative analysis identifies analytes, while quantitative analysis determines the numerical amount or concentration.

<span class="mw-page-title-main">Microscopy</span> Viewing of objects which are too small to be seen with the naked eye

Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye. There are three well-known branches of microscopy: optical, electron, and scanning probe microscopy, along with the emerging field of X-ray microscopy.

<span class="mw-page-title-main">Spectroscopy</span> Study involving matter and electromagnetic radiation

Spectroscopy is the general field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory (LIGO)

<span class="mw-page-title-main">Scanning electron microscope</span> Type of electron microscope

A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography and composition of the sample. The electron beam is scanned in a raster scan pattern, and the position of the beam is combined with the intensity of the detected signal to produce an image. In the most common SEM mode, secondary electrons emitted by atoms excited by the electron beam are detected using a secondary electron detector. The number of secondary electrons that can be detected, and thus the signal intensity, depends, among other things, on specimen topography. Some SEMs can achieve resolutions better than 1 nanometer.

<span class="mw-page-title-main">Cathodoluminescence</span>

Cathodoluminescence is an optical and electromagnetic phenomenon in which electrons impacting on a luminescent material such as a phosphor, cause the emission of photons which may have wavelengths in the visible spectrum. A familiar example is the generation of light by an electron beam scanning the phosphor-coated inner surface of the screen of a television that uses a cathode ray tube. Cathodoluminescence is the inverse of the photoelectric effect, in which electron emission is induced by irradiation with photons.

<span class="mw-page-title-main">Surface science</span> Study of physical and chemical phenomena that occur at the interface of two phases

Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid–liquid interfaces, solid–gas interfaces, solid–vacuum interfaces, and liquid–gas interfaces. It includes the fields of surface chemistry and surface physics. Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis, semiconductor device fabrication, fuel cells, self-assembled monolayers, and adhesives. Surface science is closely related to interface and colloid science. Interfacial chemistry and physics are common subjects for both. The methods are different. In addition, interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces.

<span class="mw-page-title-main">Electron energy loss spectroscopy</span>

In electron energy loss spectroscopy (EELS) a material is exposed to a beam of electrons with a known, narrow range of kinetic energies. Some of the electrons will undergo inelastic scattering, which means that they lose energy and have their paths slightly and randomly deflected. The amount of energy loss can be measured via an electron spectrometer and interpreted in terms of what caused the energy loss. Inelastic interactions include phonon excitations, inter- and intra-band transitions, plasmon excitations, inner shell ionizations, and Cherenkov radiation. The inner-shell ionizations are particularly useful for detecting the elemental components of a material. For example, one might find that a larger-than-expected number of electrons comes through the material with 285 eV less energy than they had when they entered the material. This is approximately the amount of energy needed to remove an inner-shell electron from a carbon atom, which can be taken as evidence that there is a significant amount of carbon present in the sample. With some care, and looking at a wide range of energy losses, one can determine the types of atoms, and the numbers of atoms of each type, being struck by the beam. The scattering angle can also be measured, giving information about the dispersion relation of whatever material excitation caused the inelastic scattering.

<span class="mw-page-title-main">Synchrotron light source</span>

A synchrotron light source is a source of electromagnetic radiation (EM) usually produced by a storage ring, for scientific and technical purposes. First observed in synchrotrons, synchrotron light is now produced by storage rings and other specialized particle accelerators, typically accelerating electrons. Once the high-energy electron beam has been generated, it is directed into auxiliary components such as bending magnets and insertion devices in storage rings and free electron lasers. These supply the strong magnetic fields perpendicular to the beam which are needed to convert high energy electrons into photons.

A microprobe is an instrument that applies a stable and well-focused beam of charged particles to a sample.

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<span class="mw-page-title-main">X-ray nanoprobe</span>

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Polymer characterization is the analytical branch of polymer science.

Lipid bilayer characterization is the use of various optical, chemical and physical probing methods to study the properties of lipid bilayers. Many of these techniques are elaborate and require expensive equipment because the fundamental nature of the lipid bilayer makes it a very difficult structure to study. An individual bilayer, since it is only a few nanometers thick, is invisible in traditional light microscopy. The bilayer is also a relatively fragile structure since it is held together entirely by non-covalent bonds and is irreversibly destroyed if removed from water. In spite of these limitations dozens of techniques have been developed over the last seventy years to allow investigations of the structure and function of bilayers. The first general approach was to utilize non-destructive in situ measurements such as x-ray diffraction and electrical resistance which measured bilayer properties but did not actually image the bilayer. Later, protocols were developed to modify the bilayer and allow its direct visualization at first in the electron microscope and, more recently, with fluorescence microscopy. Over the past two decades, a new generation of characterization tools including AFM has allowed the direct probing and imaging of membranes in situ with little to no chemical or physical modification. More recently, dual polarisation interferometry has been used to measure the optical birefringence of lipid bilayers to characterise order and disruption associated with interactions or environmental effects.

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Ultrafast scanning electron microscopy (UFSEM) is an innovative consolidated facility that combines two microscopic modalities, Pump-probe microscopy and Scanning electron microscope, to gather temporal and spatial resolution phenomena. In fact, this technique is very wonderful at which ultrashort laser will be used for pump excitation of the material and the sample response will be detected by an Everhart-Thornley detector. Acquiring data depends mainly on formation of images by raster scan mode after pumping with short laser pulse at different delay times. The characterization of the output image will be done through the temporal resolution aspect. Thus, the idea is to exploit the shorter DeBroglie wavelength in respect to the photons which has great impact to increase the resolution about 1 nm. That technique is an up-to-date approach to study the dynamic of charge on material surfaces.

References

  1. Kumar, Sam Zhang, Lin Li, Ashok (2009). Materials characterization techniques. Boca Raton: CRC Press. ISBN   978-1420042948.
  2. 1 2 Leng, Yang (2009). Materials Characterization: Introduction to Microscopic and Spectroscopic Methods. Wiley. ISBN   978-0-470-82299-9.
  3. Zhang, Sam (2008). Materials Characterization Techniques. CRC Press. ISBN   978-1420042948.
  4. Mathys, Daniel, Zentrum für Mikroskopie, University of Basel: Die Entwicklung der Elektronenmikroskopie vom Bild über die Analyse zum Nanolabor, p. 8
  5. Patent US4724318 – Atomic force microscope and method for imaging surfaces with atomic resolution – Google Patents
  6. Brown, Dwayne (October 30, 2012). "NASA Rover's First Soil Studies Help Fingerprint Martian Minerals". NASA . Retrieved October 31, 2012.
  7. "What is X-ray Photon Correlation Spectroscopy (XPCS)?". sector7.xray.aps.anl.gov. Archived from the original on 2018-08-22. Retrieved 2016-10-29.
  8. R. Truell, C. Elbaum and C.B. Chick., Ultrasonic methods in solid state physics New York, Academic Press Inc., 1969.
  9. Ahi, Kiarash; Shahbazmohamadi, Sina; Asadizanjani, Navid (2018). "Quality control and authentication of packaged integrated circuits using enhanced-spatial-resolution terahertz time-domain spectroscopy and imaging". Optics and Lasers in Engineering. 104: 274–284. Bibcode:2018OptLE.104..274A. doi:10.1016/j.optlaseng.2017.07.007.