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Characterization (materials science)

Study of material structure and properties

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Characterization in materials science is 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. 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, while others use the term to refer to any materials analysis process including macroscopic techniques such as mechanical testing, thermal analysis and density calculation. 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.

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. More recently, atomic force microscopy has further increased the maximum possible resolution for analysis of certain samples in the last 30 years.

01Microscopy

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:

Optical microscopy image of aluminium
Optical microscopy image of aluminium
Image of a graphite surface at an atomic level obtained by an STM
Image of a graphite surface at an atomic level obtained by an STM

02Spectroscopy

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

Mass spectrometry

Nuclear spectroscopy

Other

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

03Macroscopic testing

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

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.
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.
(a) effective refractive indexes and (b) absorption coefficients of integrated circuits obtained via terahertz spectroscopy
(a) effective refractive indexes and (b) absorption coefficients of integrated circuits obtained via terahertz spectroscopy
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Sources and credits

This article is adapted from the Wikipedia article Characterization (materials science), written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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