Introduction to Materials Science: Crystal Structures and Materials Groups

Materials science flashcards covering crystal structures, unit cells, materials groups (metals, ceramics, polymers, composites), and carbon allotropes based on the lecture notes by dr. Linda Beenaerts' lecture notes.

Materiaalkunde

The study of technical materials and their properties, focusing on the relationship between a material's structure and its application in a product.

Technical materials (Technische materialen)

The specific materials used to create products, constructions, machines, and other engineered objects.

Long Range Order (LRO)

A characteristic of crystalline materials where atoms are arranged in a regular, repeating pattern over large distances.

Short Range Order (SRO)

A characteristic of amorphous materials, such as glass and certain plastics, where atoms lack long-range repetition but may have localized organization.

Unit cell (Eenheidscel)

The smallest structural unit of a crystal identified by three sides ($a$, $b$, and $c$) and three angles ($\alpha$, $\beta$, and $\gamma$).

Cubic system (Kubisch)

A crystal system where the axial relationships are $a = b = c$ and the interaxial angles are $\alpha = \beta = \gamma = 90^\circ$.

Hexagonal system (Hexagonaal)

A crystal system where the axial relationships are $a = b \neq c$ and the interaxial angles are $\alpha = \beta = 90^\circ$ and $\gamma = 120^\circ$.

KRC (BCC)

Kubus ruimtelijk gecentreerd (Body Centered Cubic); a metallic unit cell structure found in materials like $\alpha\text{-Fe}$, $V$, $Cr$, $Mo$, and $W$.

KVC (FCC)

Kubus vlak gecentreerd (Face Centered Cubic); a metallic unit cell structure found in materials like $\gamma\text{-Fe}$, $Al$, $Ni$, $Cu$, $Ag$, $Pt$, and $Au$.

HDP (HCP)

Hexagonaal dichtste pakking (Hexagonal Close-Packed); a metallic unit cell structure found in materials like $Be$, $Mg$, $Zn$, and $Zr$, characterized by an …ABAB… stacking sequence.

Coordination Number (CN)

The number of nearest neighboring atoms in contact with a specific atom; it serves as a measure of atomic packing efficiency.

Atomic Packing Factor (APF)

The fraction of volume in a unit cell occupied by atoms, calculated as \frac{(\text{# atoms per unit cell}) \times (\text{volume of 1 atom})}{\text{volume of unit cell}}. For KVC and HDP, this value is $0.74$.

Allotropy

The phenomenon where certain solid elements can exist in more than one crystal structure depending on temperature and/or pressure.

White tin ($\beta\text{-Sn}$)

The allotropic form of tin that is stable at room temperature, featuring a tetragonal body-centered lattice.

Gray tin ($\alpha\text{-Sn}$)

The allotropic form of tin stable at temperatures below $13.2\,^\circ\text{C}$, featuring a cubic diamond lattice and appearing in powder form.

Tinpest

The spontaneous transformation of white tin into powdery gray tin when held at very low temperatures for a long period.

Ceramic materials

Inorganic, non-metallic materials with complex crystal structures often following formulas like $MX$, $MX_2$, or $M_2X_3$.

Cation ($r_K$)

A positively charged metal ion, which is typically smaller in radius than an anion.

Anion ($r_A$)

A negatively charged non-metal ion, which is typically larger in radius than a kation.

Graphite

An allotrope of carbon consisting of parallel layers with hexagonal structures held together by covalent bonds within the planes and Van der Waals interactions between them.

Diamond

A high-pressure stabilized form of carbon where each atom is covalently bonded to four others in a tetrahedral arrangement, resulting in extreme hardness.

Buckminsterfullerene ($C_{60}$)

A carbon molecule containing 20 hexagons and 12 pentagons, named after R. Buckminster Fuller; it crystallizes in an FCC lattice.

Carbon nanotubes

Also known as buckytubes, these consist of a single rolled-up layer of graphite with lengths up to a thousand times larger than their diameter.

Theoretical Density formula

\frac{(\text{# atoms per unit cell}) \times (\text{atomic mass of 1 atom})}{\text{volume of the unit cell}}.