FAQ

Glossary

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A

Abradable Seals

A seal made from mating two soft metal, or metal containing soft graphite, surfaces together using friction and pressure.

Abrasion

To wear away by friction.

Adhesion

A binding force that holds together molecules of substances whose surfaces are in contact or near proximity.

Alumina

Aluminum oxide; a ceramic used in powder or rod form in thermal spray operations.

Anode

The electrode maintained at a positive electrical potential.

Arc

A luminous discharge of electrical current crossing the gap between two electrodes.

Arc spraying

A thermal spraying process using an arc between two consumable electrodes of surfacing materials as a heat source and a compressed gas to atomize and propel the surfacing material to the substrate.

Atmospheric Plasma Spraying (APS)

A plasma spray method done in open air.

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B

Bio-active

Any material that encourages growth, such as bone growth, when implanted in the body. Bio-active material is used as a coating on dental and orthopaedic implants in order to create a bond to bone in the body.

Bio-inert

Any material that does not harm and is not rejected by the body when implanted. This material is often used as a surface coating on dental and orthopaedic implants.

Bond strength

The force required to pull a coating free of a substrate, usually expressed in kPa (psi).

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C

Carbide

A chemical compound formed between carbon and a metal or metals; examples include tungsten carbide, tantalum carbide, titanium carbide, chromium carbide. One of the hardest examples is boron carbide.

Cathode

The electrode maintained at a negative electric potential.

Ceramic

Any of the various hard, heat-resistant, and corrosion resistant coatings made up of non-metallic materials.

Cermets

A mixture of ceramics and metals used as a thermal spray material.

Coating

(1) The act of building a deposit on a substrate, (2) The spray deposit.

Composite coating

A coating consisting of two or more dissimilar spray materials which may or may not be layered.

Controlled atmosphere chamber

An enclosure or cabinet filled either with an inert gas or evacuated to below atmospheric pressure, in which thermal spraying can be performed to minimize or prevent oxidation of the coating or substrate.

Corrosion

To wear away gradually, especially by chemical action.

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D

Deposition rate

The weight of material deposited in a unit of time.

Dielectric coatings

A coating that serves as a non-conductor of electricity.

Dry Film Coating

Dry film lubricants coatings are designed to create a permanent lubricated surface to impede galling and the seizing of components, making them especially valuable to the automotive industry.

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E

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F

Feed rate

A nonstandard term for spray rate.

Flame spray

A thermal spray process in which an oxyfuel gas flame is the source of heat for melting the surfacing material. Compressed gas may or may not be used for atomizing and propelling the surfacing material to the substrate.

Fretting

Surface damage resulting from relative motion between surfaces in contact under pressure.

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G

Gradated coating

A thermal spray deposit composed of mixed materials in successive layers that progressively change in composition from the constituent material lot to the surface of the sprayed deposit.

Grit blasting

The preparation of a substrate for the thermal spray process by blasting with sharp irregular shaped grains to produce a pitted surface.

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H

Hardfacing

A surfacing variation in which the surfacing metal is deposited to reduce wear.

Heat Dissipation Coatings

Micro Dyne’s heat dissipation coatings transfer heat away from a substrate, resulting in improved efficiencies, performance and longevity of the coated parts, making these coatings particularly desirable to the automotive industry.

HVOF (High Velocity Oxygen Fuel)

A high velocity flame spray process.

Hydroxyapatite (HA)

Hydroxyapatite (HA) largely consists of calcium and phosphorous. This composition allows HA to function in the biomedical industry as a coating that promotes osseointegration between bone and various orthopedic implants.

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I

Inert gas

A gas that does not normally combine with the substrate or the deposit.

Interface

The contact surface between the spray deposit and the substrate.

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J

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K

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L

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M

Mask

A device for protecting a substrate surface from the effects of blasting or adherence of a spray deposit.

Mechanical bond

The adherence of a thermal spray deposit to a roughened surface by the mechanism of interlocking particles.

Metallic bond

The principal bond that holds metals together and is formed between base metals and filler metals in all processes.

Metallurgical bond

(see above)

Molten metal flame spraying

A thermal spraying process variation in which the metallic material to be sprayed is in the molten state. (see flame spray)

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N

Near Net Shapes

In the thermal spray process, the substrate is removed after application to leave a seamless, solid shape.

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O

Osseointegration

The characteristic of hydroxyapatite and titanium that allow those substances to organically fuse with human bone.

Overspray

The excess spray material that is not deposited on the part being sprayed.

Oxide

A chemical compound; the combination of oxygen with a metal forming a ceramic; ex. Aluminum oxide.

Oxyfuel gas spraying

A nonstandard term for flame spraying.

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P

Plasma Spraying

A thermal spray process in which a nontransferred arc is used as the source of heat that ionizes a gas which, in turn, melts and propels the coating material to the work piece.

Plasma

An electrically neutral, highly ionized gas composed of electrons, ions, and neutral particles.

Particle size

The average diameter of a given powder or grit granule.

Particle size distribution

Classification of powdered materials as determined by various testing methods, defining the particle sizes and quantities in a given sample.

Powder

Material manufactured into finely divided particles. When blended for thermal spraying, powder falls within a specific mesh range, usually finer than 120 mesh (125 microns).

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Q

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R

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S

Spalling

The flaking or separation of a sprayed coating.

Splat

A single sprayed particle that resembles a thin, flattened drop of liquid, under magnification.

Spray-cast

A moving mass of dispersed liquid droplets or heat softened particles deposited on a substrate.

Substrate

Any material to which a thermally sprayed deposit is applied.

Synthetic Bone Materials

Materials, such as hydroxyapatite and titanium, that exhibit properties similar to those of human bone.

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T

Thermal Spraying

A group of processes in which finely divided metallic or nonmetallic surfacing materials are deposited in a molten or semi-molten state onto a substrate to form a deposit.

Thermal Barrier Coatings

A group of ceramic coatings, including Yttria Stabilized Zirconia (YSZ) and Magnesium/Zirconate, used to protect the substrate in extreme heat environments.The heat rejection properties of TBCs excel in applications to an excess of 3000 °F. TBCs have been used successfully on piston tops, valves, exhaust systems, etc.

Torch

A device used for fusing sprayed coatings; it mixes and controls the flow of gases.

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U

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V

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W

Wear

To damage, erode or consume by long, hard use.

Wire flame spraying

A thermal spray process variation in which the surfacing materials are in wire form. (See flame spray)

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X

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Y

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Z

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