Thermal Spray Glossary H-N

Thermal Spray Glossary H-N

H

Hand Shield.
A protective device for shielding the eyes, face, and neck.
A hand shield is equipped with a filter plate and is designed to be held by hand.
Hardfacing.
A surfacing variation in which surfacing metal is deposited to reduce wear.
Helmet.
A device designed to be worn on the head to protect eyes, face, and neck from arc radiation, radiated heat, spatter, or other harmful matter.
HVOF/HVAF (High Velocity Oxygen Fuel/High Velocity Air Fuel).
A high velocity flame spray process.



I

Inert Gas.
A gas which does not normally combine chemically with the substrate or the deposit.
Typical examples are argon and helium.
Injection Angle.
Angle at which powder is injected into flame. Powder injected at 0( is injected perpendicular to the flame. Positive angles indicate injection in direction of flame; negative angles in direction against flame.
Interface.
The contact surface between the spray deposit and the substrate.
Interpass Temperature.
In multiple pass thermal spraying, the temperature (minimum or maximum as specified) of the deposited spray coating before a subsequent pass is started.
Ion.
An atom or group of atoms forming a molecule that carries a positive or negative charge as a result of having lost or gained one or more electrons.
Ionic Bond.
A primary bond arising from the electrostatic attraction between two oppositely charged ions.


J

Jet pulverizer.
A machine that comminutes metal pieces, ores, or agglomerates.
Jig.
Mechanism or fixture for holding a part and/or guiding the tool during machining, spraying or assembly operation.
Joint.
The location where two or more members meet, are to be met, or have been fastened together.
Joint clearnance.
The distance between the faying surfaces of a joing.
Joint design.
Joint deometry, including the required dimensions of the welded/brazed/bonded joint.
Joint geometry.
The shape and dimensions of a joint in cross section.
Journal.
The part of a shaft or axle that rotates or oscillates relative to a radial bearing. A journal is part of a larger unit, such as a crankshaft. It is preferred that the term "shaft" be kept for the whole unit.


K

Keying.
A nonstandard term for mechanical bond.
Knurling.
See Groove and Rotary Roughening, Threading and Knurling.



L

Lamella.
A thin layer, as in the overlayed particles in a thermal spray deposit.
Lamination.
See preferred term Lamella.
Lens.
See Filter Lens.
Locked-up Stress.
A nonstandard term for residual stress.
Low Pressure Plasma Spray.
See preferred term Vacuum Plasma Deposition.



M

Manifold.
See Cylinder Manifold.
Mask.
A device for protecting a substrate surface from the effects of blasting or adherence of a spray deposit.
Matrix.
The major continuous substance of a thermal spraying coating as opposed to inclusions or particles of materials having dissimilar characteristics.
Mechanical Bond.
The adherence of a thermal spraying deposit to a roughened surface by the mechanism of particle interlocking.
Melting Rate.
The weight or length of spray wire or rod melted in a unit of time.
Metallic Bond.
The principal bond that holds metals together and is formed between base metals and filler metals in all processes.
This is a primary bond arising from the increased spatial extension of the valence electron wave functions when an aggregate of metal atoms is brought close together.
See also Bonding Force, and Ionic Bond.
Metallizing.
See preferred term Thermal Spraying.
Metallurgical Bond.
A nonstandard term for metallic bond.
Molten Metal Flame Spraying.
A thermal spraying process variation in which the metallic material to be sprayed is in the molten condition. See Flame Spraying (FLSP).


N

Neat.
Unadulterated.
Neutral Flame.
An oxyfuel gas flame in which the portion used is neither oxidizing nor reducing.
See also Oxidizing Flame and Reducing Flame.
Nontransferred Arc.
An arc established between the electrode and the constricting nozzle.
The workpiece is not in the electrical circuit.
Nozzle.
(1) A device which directs shielding media, (2) a device that atomizes air in an arc spray gun, (3) the anode in a plasma gun, (4) the gas burning jet in a rod or wire flame spray gun.
Nozzle Accumulation.
Surfacing material deposited on the inner surface and on the exit end of the nozzle.