Editing Materials science (section)

==Fundamentals==
{{anchor|Fundamentals of materials science}}
{{anchor|Fundamentals of materials science|materials paradigm}}
[[File:Materials science tetrahedron;structure, processing, performance, and proprerties.svg|thumb|upright=1.14|The materials paradigm represented in the form of a tetrahedron]]
A material is defined as a substance (most often a solid, but other condensed phases can be included) that is intended to be used for certain applications.<ref>[http://www.nature.com/nmat/authors/index.html "For Authors: Nature Materials"] {{webarchive|url=https://web.archive.org/web/20100801234616/http://www.nature.com/nmat/authors/index.html |date=2010-08-01 }}</ref>  There are a myriad of materials around us; they can be found in anything from<ref>Callister, Jr.,  Rethwisch. "Materials Science and Engineering – An Introduction" (8th ed.). John Wiley and Sons, 2009 pp.5–6</ref> new and advanced materials that are being developed include [[nanomaterials]], [[biomaterial]]s,<ref>Callister, Jr.,  Rethwisch. Materials Science and Engineering – An Introduction (8th ed.)uildings and cars to spacecraft. The main classes of materials are [[metal]]s, [[semiconductor]]s, [[ceramic]]s and [[polymer]]s.. John Wiley and Sons, 2009 pp.10–12</ref> and [[Photovoltaic cell|energy materials]] to name a few.<ref>{{Cite journal |last1=Goodenough |first1=John B. |last2=Kim |first2=Youngsik |date=2009-08-28 |title=Challenges for Rechargeable Li Batteries |url=http://dx.doi.org/10.1021/cm901452z |journal=Chemistry of Materials |volume=22 |issue=3 |pages=587–603 |doi=10.1021/cm901452z |issn=0897-4756}}</ref>

The basis of materials science is studying the interplay between the structure of materials, the processing methods to make that material, and the resulting material properties. The complex combination of these produce the performance of a material in a specific application. Many features across many length scales impact material performance, from the constituent chemical elements, its [[microstructure]], and macroscopic features from processing. Together with the laws of [[thermodynamics]] and [[kinetics (physics)|kinetics]] materials scientists aim to understand and improve materials.

===Structure===
Structure is one of the most important components of the field of materials science. The very definition of the field holds that it is concerned with the investigation of "the relationships that exist between the structures and properties of materials".<ref>{{Cite book |last=Zagorodni |first=Andrei A. |title=Ion Exchange Materials: Properties and Applications |publisher=Elsevier |year=2006 |isbn=978-0-08-044552-6 |location=Amsterdam |pages=xi |language=en}}</ref> Materials science examines the structure of materials from the atomic scale, all the way up to the macro scale.<ref name=":1" /> [[Characterization (materials science)|Characterization]] is the way materials scientists examine the structure of a material. This involves methods such as diffraction with [[X-ray]]s, [[electron]]s or [[neutron]]s, and various forms of [[spectroscopy]] and [[chemical analysis]] such as [[Raman spectroscopy]], [[energy-dispersive X-ray spectroscopy|energy-dispersive spectroscopy]], [[chromatography]], [[thermal analysis]], [[electron microscope]] analysis, etc.

Structure is studied in the following levels.

====Atomic structure====
Atomic structure deals with the atoms of the materials, and how they are arranged to give rise to molecules, crystals, etc. Much of the electrical, magnetic and chemical properties of materials arise from this level of structure. The length scales involved are in angstroms ([[Angstrom|Å]]). The chemical bonding and atomic arrangement (crystallography) are fundamental to studying the properties and behavior of any material.

=====Bonding=====
{{Main|Chemical bonding}}
To obtain a full understanding of the material structure and how it relates to its properties, the materials scientist must study how the different atoms, ions and molecules are arranged and bonded to each other. This involves the study and use of [[quantum chemistry]] or [[quantum physics]]. [[Solid-state physics]], [[solid-state chemistry]] and [[physical chemistry]] are also involved in the study of bonding and structure.

=====Crystallography=====
{{Main|Crystallography}}
[[File:Perovskite.jpg|thumb|Crystal structure of a perovskite with a chemical formula ABX<sub>3</sub><ref>{{cite journal |title= Energetics and Crystal Chemical Systematics among Ilmenite, Lithium Niobate, and Perovskite Structures |author= A. Navrotsky |journal= Chem. Mater. |date= 1998 |volume= 10 |issue= 10 |pages= 2787–2793 |doi= 10.1021/cm9801901}}</ref>]]
Crystallography is the science that examines the arrangement of atoms in crystalline solids. Crystallography is a useful tool for materials scientists. One of the fundamental concepts regarding the crystal structure of a material includes the [[unit cell]], which is the smallest unit of a crystal lattice (space lattice) that repeats to make up the macroscopic crystal structure. Most common structural materials include [[Parallelepiped|parallelpiped]] and hexagonal lattice types.<ref>Callister, Jr.,  Rethwisch. "Materials Science and Engineering – An Introduction" (8th ed.) John Wiley and Sons, 2009</ref> In [[single crystal]]s, the effects of the crystalline arrangement of atoms is often easy to see macroscopically, because the natural shapes of crystals reflect the atomic structure. Further, physical properties are often controlled by crystalline defects. The understanding of crystal structures is an important prerequisite for understanding [[crystallographic defect]]s. Examples of crystal defects consist of dislocations including edges, screws, vacancies, self inter-stitials, and more that are linear, planar, and three dimensional types of defects.<ref>Callister, Jr.,  Rethwisch. "Materials Science and Engineering – An Introduction" (8th ed.). John Wiley and Sons, 2009</ref> New and advanced materials that are being developed include [[nanomaterials]], [[biomaterial]]s.<ref>Callister, Jr.,  Rethwisch. Materials Science and Engineering – An Introduction (8th ed.)</ref> Mostly, materials do not occur as a single crystal, but in polycrystalline form, as an aggregate of small crystals or grains with different orientations. Because of this, the [[Powder diffraction|powder diffraction method]], which uses diffraction patterns of polycrystalline samples with a large number of crystals, plays an important role in structural determination. Most materials have a crystalline structure, but some important materials do not exhibit regular crystal structure.<ref>{{Cite journal |last=Gavezzotti |first=Angelo |date=1994-10-01 |title=Are Crystal Structures Predictable? |url=http://dx.doi.org/10.1021/ar00046a004 |journal=Accounts of Chemical Research |volume=27 |issue=10 |pages=309–314 |doi=10.1021/ar00046a004 |issn=0001-4842}}</ref> [[Polymer]]s display varying degrees of crystallinity, and many are completely non-crystalline. [[Glass]], some ceramics, and many natural materials are [[Amorphous solid|amorphous]], not possessing any long-range order in their atomic arrangements. The study of polymers combines elements of chemical and statistical thermodynamics to give thermodynamic and mechanical descriptions of physical properties.

====Nanostructure====
{{Main|Nanostructure}}
[[File:Buckminsterfullerene-perspective-3D-balls.png|thumb|left|upright=0.7|[[Buckminsterfullerene]] nanostructure]]
Materials, which atoms and molecules form constituents in the nanoscale (i.e., they form nanostructures) are called nanomaterials. Nanomaterials are the subject of intense research in the materials science community due to the unique properties that they exhibit.

Nanostructure deals with objects and structures that are in the 1 – 100&nbsp;nm range.<ref>{{cite journal |url= http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=BJIOBN00000200000400MR17000001&idtype=cvips&gifs=Yes |author= Cristina Buzea |author2= Ivan Pacheco |author3= Kevin Robbie |name-list-style= amp |title= Nanomaterials and Nanoparticles: Sources and Toxicity |journal= Biointerphases |volume= 2 |date= 2007 |pages= MR17–MR71 |doi= 10.1116/1.2815690 |pmid= 20419892 |issue= 4 |url-status= live |archive-url= https://archive.today/20120703014917/http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=BJIOBN00000200000400MR17000001&idtype=cvips&gifs=Yes |archive-date= 2012-07-03 |arxiv= 0801.3280 |s2cid= 35457219 }}</ref>  In many materials, atoms or molecules agglomerate to form objects at the nanoscale. This causes many interesting electrical, magnetic, optical, and mechanical properties.

In describing nanostructures, it is necessary to differentiate between the number of dimensions on the [[Nanoscopic scale|nanoscale]].

[[Nanotextured surface]]s have ''one dimension'' on the nanoscale, i.e., only the thickness of the surface of an object is between 0.1 and 100&nbsp;nm.

Nanotubes have ''two dimensions'' on the nanoscale, i.e., the diameter of the tube is between 0.1 and 100&nbsp;nm; its length could be much greater.

Finally, spherical [[nanoparticle]]s have ''three dimensions'' on the nanoscale, i.e., the particle is between 0.1 and 100&nbsp;nm in each spatial dimension. The terms nanoparticles and [[ultrafine particle]]s (UFP) often are used synonymously although UFP can reach into the micrometre range. The term 'nanostructure' is often used, when referring to magnetic technology. Nanoscale structure in biology is often called [[ultrastructure]].

====Microstructure====
{{Main|Microstructure}}
[[File:Pearlite.jpg|thumb|right|Microstructure of pearlite]]
Microstructure is defined as the structure of a prepared surface or thin foil of material as revealed by a microscope above 25× magnification. It deals with objects from 100&nbsp;nm to a few cm. The microstructure of a material (which can be broadly classified into metallic, polymeric, ceramic and composite) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behavior, wear resistance, and so on.<ref>{{Cite journal |last1=Filip |first1=R |last2=Kubiak |first2=K |last3=Ziaja |first3=W |last4=Sieniawski |first4=J |date=2003 |title=The effect of microstructure on the mechanical properties of two-phase titanium alloys |url=http://dx.doi.org/10.1016/s0924-0136(02)00248-0 |journal=Journal of Materials Processing Technology |volume=133 |issue=1–2 |pages=84–89 |doi=10.1016/s0924-0136(02)00248-0 |issn=0924-0136}}</ref> Most of the traditional materials (such as metals and ceramics) are microstructured.

The manufacture of a perfect [[crystal]] of a material is physically impossible. For example, any crystalline material will contain [[crystallographic defect|defects]] such as [[Precipitation (chemistry)|precipitates]], grain boundaries ([[Hall–Petch|Hall–Petch relationship]]), vacancies, interstitial atoms or substitutional atoms.<ref>{{Citation |title=Crystal Structure Defects and Imperfections |date=2021-10-01 |url=http://dx.doi.org/10.31399/asm.tb.ciktmse.t56020001 |work=Crystalline Imperfections: Key Topics in Materials Science and Engineering |pages=1–12 |access-date=2023-10-29 |publisher=ASM International|doi=10.31399/asm.tb.ciktmse.t56020001 |isbn=978-1-62708-389-8 |s2cid=244023491 }}</ref> The microstructure of materials reveals these larger defects and advances in simulation have allowed an increased understanding of how defects can be used to enhance material properties.

====Macrostructure====
Macrostructure is the appearance of a material in the scale millimeters to meters, it is the structure of the material as seen with the naked eye.

===Properties===
{{Main|List of materials properties}}
Materials exhibit myriad properties, including the following.
:*Mechanical properties, see [[Strength of materials]]
:*Chemical properties, see [[Chemistry]]
:*Electrical properties, see [[Electricity]]
:*Thermal properties, see [[Thermodynamics]]
:*Optical properties, see [[Optics]] and [[Photonics]]
:*Magnetic properties, see [[Magnetism]]
The properties of a material determine its usability and hence its engineering application.

===Processing===
Synthesis and processing involves the creation of a material with the desired micro-nanostructure. A material cannot be used in industry if no economically viable production method for it has been developed. Therefore, developing processing methods for materials that are reasonably effective and cost-efficient is vital to the field of materials science. Different materials require different processing or synthesis methods. For example, the processing of metals has historically defined eras such as the [[Bronze Age]] and [[Iron Age]] and is studied under the branch of materials science named ''physical [[metallurgy]]''. Chemical and physical methods are also used to synthesize other materials such as [[polymer]]s, [[ceramic]]s, [[semiconductor]]s, and [[thin film]]s. As of the early 21st century, new methods are being developed to synthesize nanomaterials such as [[graphene]].<ref name="z969">{{cite journal | last1=Mbayachi | first1=Vestince B. | last2=Ndayiragije | first2=Euphrem | last3=Sammani | first3=Thirasara | last4=Taj | first4=Sunaina | last5=Mbuta | first5=Elice R. | last6=khan | first6=Atta ullah | title=Graphene synthesis, characterization and its applications: A review | journal=Results in Chemistry | volume=3 | date=2021 | doi=10.1016/j.rechem.2021.100163 | doi-access=free | page=100163}}</ref>

===Thermodynamics===
{{Main|Thermodynamics}}
[[File:Eutektikum new.svg|thumb|left|upright=1.15|A phase diagram for a binary system displaying a eutectic point]]
Thermodynamics is concerned with [[heat]] and [[temperature]] and their relation to [[energy]] and [[Work (thermodynamics)|work]]. It defines [[macroscopic scale|macroscopic]] variables, such as [[internal energy]], [[entropy]], and [[pressure]], that partly describe a body of matter or radiation. It states that the behavior of those variables is subject to general constraints common to all materials. These general constraints are expressed in the four laws of thermodynamics. Thermodynamics describes the bulk behavior of the body, not the microscopic behaviors of the very large numbers of its microscopic constituents, such as molecules. The behavior of these microscopic particles is described by, and the laws of thermodynamics are derived from, [[statistical mechanics]].

The study of thermodynamics is fundamental to materials science. It forms the foundation to treat general phenomena in materials science and engineering, including chemical reactions, magnetism, polarizability, and elasticity.<ref>{{Cite journal |last=Liu |first=Zi-Kui |date=2020 |title=Computational thermodynamics and its applications |journal=Acta Materialia |volume=200 |pages=745–792 |doi=10.1016/j.actamat.2020.08.008 |bibcode=2020AcMat.200..745L |s2cid=225430517 |issn=1359-6454|doi-access=free }}</ref> It explains fundamental tools such as [[phase diagram]]s and concepts such as phase [[Thermodynamic Equilibrium|equilibrium]].

===Kinetics===
{{Main|Chemical kinetics}}
[[Chemical kinetics]] is the study of the rates at which systems that are out of equilibrium change under the influence of various forces. When applied to materials science, it deals with how a material changes with time (moves from non-equilibrium to equilibrium state) due to application of a certain field. It details the rate of various processes evolving in materials including shape, size, composition and structure. [[Diffusion]] is important in the study of kinetics as this is the most common mechanism by which materials undergo change.<ref>{{Cite book |last1=Kärger |first1=Jörg |url=http://dx.doi.org/10.1002/9783527651276 |title=Diffusion in Nanoporous Materials |last2=Ruthven |first2=Douglas M. |last3=Theodorou |first3=Doros N. |date=2012-04-25 |publisher=Wiley |doi=10.1002/9783527651276 |isbn=978-3-527-31024-1}}</ref> Kinetics is essential in processing of materials because, among other things, it details how the microstructure changes with application of heat.