Ceramics, Glass, Polymers, and Composites Lecture

Vocabulary flashcards covering the manufacturing processes, structural properties, and classifications of ceramics, glass, polymers, and composite materials from the lecture transcript.

Ceramics

A family of materials characterized by brittle behavior, high strength, electrical and thermal insulation, and very high melting points.

Ionic and Covalent Bonding

The primary chemical bonds found in ceramics that prevent atomic slip by forcing like charges together or sharing electrons, resulting in high melting points and brittleness.

Green Part

A temporary, weak, and unstable shaped object created by compacting powders or granules before the material is sintered or fired.

Sintering

The manufacturing process where particles are heated in a kiln to permanently fuse them via diffusion, creating a strong solid part.

Slip Casting

A ceramic shaping process where a slurry (slip) is poured into a porous mold; the mold absorbs water, causing a layer of clay to build up on the interior surface.

Amorphous

A microstructural state lacking a crystalline unit cell or repeating atomic arrangement, typical of materials like glass and certain liquids.

Silica ($SiO_2$)

The main constituent of glass, making up at least $50\%$ of its composition.

Surface Flaws/Cracks

Microscopic defects present on the surface of ceramics and glass that make them sensitive to fracture under tensile stress.

Float Glass

A process for manufacturing perfectly flat window glass by pouring molten glass onto a bath of molten tin.

Tempering

The process of rapidly cooling (quenching) glass from a hot state to generate compressive stresses at the surface, significantly increasing its strength.

Laminated Glass

Safe glass constructed by placing a thin polymer layer between sheets of glass to contain fragments upon impact.

Polymers

Materials made of long chains of covalently bonded atoms, often featuring a carbon-carbon backbone.

Mers

The smallest repeating structural units in a polymer, analogous to unit cells in metals.

Linear Polymers

Polymer structures consisting of simple, straight chains that are the easiest to decoil and stretch, offering high ductility but low strength.

Cross-linked Polymers

Polymer morphologies where chains are connected to each other, resulting in significantly higher strength and rigidity but reduced ductility.

Thermoplastics

Polymers that can be repeatedly melted and resolidified, making them easier to recycle compared to other plastic types.

Thermosets

Polymers that form permanent chemical networks during curing; they do not melt when reheated and are difficult to recycle.

Glass Transition Point ($T_g$)

The specific temperature below which a polymer behaves as a brittle, glassy solid and above which it behaves as a ductile, rubbery material.

Crystallinity (in Polymers)

The degree to which polymer chains are aligned in a repeating pattern, which increases the material's density and strength while lowering ductility.

PHA (Polyhydroxyalkanoate)

A biodegradable polymer derived from bacteria that store the material as the equivalent of fat.

Composites

Combinations of different material classes (e.g., metal and ceramic) formulated to blend properties like strength, ductility, and weight.

Fiber-Reinforced Composite

A material consisting of high-strength fibers (like carbon or glass) embedded in a matrix material.

Rule of Mixtures

A method to calculate the properties of a composite by summing the property of each phase multiplied by its volume fraction (e.g., $E_{composite} = E_{fiber}V_{f} + E_{matrix}V_{m}$).

Anisotropic Properties

Mechanical characteristics that vary depending on the direction of loading, common in unidirectional fiber-reinforced composites.

Isotropic Properties

Mechanical properties that are the same in all directions, often achieved in composites by layering fiber plies in alternating orientations.

Prepreg

Fiber sheets that have been pre-impregnated with resin, requiring only heat and pressure to cure into a final part.

Autoclave

A pressurized oven used in composite manufacturing to accelerate the cross-linking or curing process.