Materials and Processes: Surface Properties, Friction, Wear, and Lubrication

Vocabulary practice flashcards covering surface characteristics, surface texture components, manufacturing flaws, friction, wear types, surface hardening treatments, and lubrication methods from the lecture notes.

Surface

The outside part or uppermost layer of something, which is touched when holding an object.

Surface Texture

The deviation from the nominal or normal surface of an object, comprised of roughness, waviness, lay, and flaws.

Roughness

The small, finely spaced deviations from the nominal surface.

Waviness

Surface deviations of much larger spacing than roughness.

Lay

The predominant direction or pattern of the surface texture, determined by the manufacturing method used to create the surface.

Flaws

Irregularities that occur occasionally on the surface, including defects such as cracks, scratches, and inclusions.

Surface Integrity

The surface condition of a workpiece after being modified by a manufacturing process (such as welding, machining, or casting), which can alter both the part's surface and the subsurface layer.

Void (Manufacturing Flaw)

A hole or cavity defect within a material or weld that can compromise component safety and visual quality.

Friction

A resistive force that acts between two surfaces in contact, directed opposite to the direction of the applied force.

Wear

The progressive loss of material from a surface, commonly caused by abrasion, fatigue, or corrosion.

Abrasive Wear

A type of wear that occurs when a hard, rough surface slides across a softer surface, or when grit such as sand or dirt rubs between the contacting surfaces.

Surface Fatigue Wear

Wear caused by repeated cyclic loading and unloading on a surface, such as the contact stress exerted by steel train wheels on a railway track.

Fatigue Fracture Zones

The distinctive developmental regions visible on a fatigue fracture face, consisting of the initiation zone (origin with pitting), the progression zone, and the final fracture zone.

Corrosion Wear

Wear resulting from chemical or electrochemical degradation and deterioration of a metal surface.

Carburizing

A surface-hardening method that involves heating a low-carbon steel part in a carbon-rich environment at approximately $875\,^\circ\text{C}\text{ to }925\,^\circ\text{C}$ to diffuse carbon into the outer layer while keeping the core tough and ductile.

Nitriding

A surface treatment process used to increase surface hardness by creating a hard layer of nitride ceramic on the surface.

Carbonitriding

A surface treatment in which both carbon and nitrogen are absorbed into a steel surface, typically by heating in a furnace atmosphere containing carbon and ammonia.

Lubrication

The introduction of a fluid layer between two contacting surfaces to separate them, thereby reducing friction and wear.

Surface

The outside part or uppermost layer of something, representing what one touches when holding an object.

Surface Texture

The deviation from the normal surface of an object.

Roughness

Small, finely spaced deviations from the nominal surface.

Waviness

Deviations from the surface of much larger spacing.

Lay

The predominant direction or pattern of the surface texture, determined by the manufacturing method used to create the surface.

Flaws

Irregularities that occur occasionally on a surface, including cracks, scratches, inclusions, and similar defects.

Surface Integrity

The surface condition of a workpiece after being modified by a manufacturing process such as welding, machining, or casting.

Surface Cracks

A common type of manufacturing flaw that can compromise component safety and alter its appearance.

Voids

Holes that form as manufacturing defects within a material or weld, impacting both component safety and appearance.

Friction

A force that acts between two surfaces in contact, acting in the opposite direction of the applied force.

Wear

The loss of material from a surface, primarily caused by abrasion, fatigue, or corrosion.

Abrasive Wear

Wear that occurs when a hard, rough surface slides across a softer surface, or when sand or dirt rubs between the surfaces.

Surface Fatigue Wear

Wear caused by repeated mechanical loading and unloading on a surface, such as the high pressure exerted by steel train wheels on a rail track.

Corrosion Wear

Wear caused by the chemical degradation and corrosion of a metal surface.

Carburizing

A surface-hardening process involving heating a low-carbon steel component in a carbon-rich environment at approximately $875$ to $925\,^\circ\text{C}$ so carbon diffuses into the surface while the internal region remains tough and ductile.

Nitriding

A surface-hardening method used to create a layer of hard nitride ceramic directly on the surface of a metal part.

Carbonitriding

A case-hardening treatment in which both carbon and nitrogen are absorbed into a steel surface, typically by heating in a furnace atmosphere containing carbon and ammonia.

Lubricant

A substance that introduces a layer of fluid between two contacting surfaces to eliminate direct contact and reduce wear and friction.