Glossary Terms

Alloy

An alloy is defined as a blend of metals (or other elements) in a solid solution.

Alloy Powder

An alloy powder is created from a single molten alloy.

Amorphous materials

A material made up of particles that lack long range order. It does not exhibit an ordered structure be deposited to create an excellent corrosion and wear resistant material.

Bond Strength

Bond strength refers to the adhesion power between the coating and substrate. For cold spray applications, this is typically >10 kilopounds per square inch (KSI).

Carrier Gas

A carrier gas is a gas conveying the metal powder from the powder feeder to the surfacing gun.

Chemical Compatibility

The measure of how stable a certain substance is when mixed with one or more additional substances.

Coating Strength

Coating strength is also referred to as spray deposit strength. Typical values achieved exceed 40 ksi.

Combustion

The rapid chemical combination of a substance with oxygen, involving the production of heat and light.

Composite Powder

A composite powder that combines metal particles with two or more individual materials

Conductivity

The ability of a body structure to transmit an electric impulse, most often presenting as heat and light.

Corrosion

Corrosion is the chemical (or the electrochemical) reaction of the substrate with its environment leading to its deterioration. A typical example of electrochemical corrosion is rust.

Critical Velocity

The critical velocity is the speed at which a spray of metal particles transitions from eroding the target surface to coating it instead

De Laval Nozzle

A de Laval nozzle is a nozzle that converts heat energy in the gas to kinetic energy (speed!). A slow, high-temperature gas goes in, and a fast and lower-temperature gas comes out.

Density

The measure of mass per unit volume. Cold spray has the ability to apply a dense surface coating which is durable and corrosion resistant.

Deposition Rate

The deposition rate refers to the weight of material deposited onto the substrate over a given time. This is usually measured in kilograms/hr (kg/h) or pounds/hr (lb/h).

Ductility

The ability for a solid material to deform under tensile stress, often related to materials that can easily be stretched into wire.

Elastic Deformation

Elastic deformation occurs in the material below the yield strength and is fully recovered when the load is removed. This is very similar to stretching and releasing a spring.

Electromagnetic Interference (EMI) Shielding

This barrier occurs when using conductive or magnetic materials to form a barrier against electromagnetic fields. Electromagnetic shielding that also blocks radio frequencies is known as RF shielding.

Feed Rate

The feed rate is when the consumable alloy, metal, or composite powder is “fed through” the cold spray system

Field Repair

The portability of cold spray systems allows you to take the solution to the component, which is a highly cost-effective way to handle extensive component repairs. Repairing in the field is referred to as a “field repair.”

Gas Flow Rate

The gas flow rate is when the gas, usually measured in liters per minute, flows through the cold spray de Laval nozzle.

Grain Structure

The arrangement of differently oriented particles. When using cold spray technology, the angle of application and force at which particles are applied creates a unique grain structure.

Heat-Affected Zone (HAZ)

The HAZ refers to the substrate area that increases in temperature due to the coating application. Cold spray has an inappreciable heat input, thereby minimizing the heat-affected zone on the substrate

Helium

Helium is a low-density, inert gas used for filling balloons and airships. It is often used in the cold spray process due to its high speed of sound.

Mechanical Interlocking

Mechanical interlocking is a mechanical “blending” of the impacting particles and the substrate or previously deposited layers of particles that effectively interlock the layers. This interlocking result can transfer load and resist motion, even if the particles are not metallurgically bonded to the substrate or other particles.

Metal Powder

A metal powder is a powder consisting of a single, pure metal. The size for cold spray powders ranges from five to one hundred micrometers in diameter.

Metallurgical Bon

A metallurgical bond is a type of chemical bond between atoms in a metallic element. Metallic bonding yields specific property characteristics in metals, such as conductivity, ductility, and strength.

Nanomaterials

A material that measures between 1 and 100 nanometers, cold spray with nanomaterials offers improved physical and mechanical properties and forms significantly stronger structural bonds.

Nitrogen

Like helium, nitrogen is also an inert gas often used as a carrier gas in cold spray. Nitrogen constitutes over 78% of the earth’s atmosphere, yet it will not support life, nor is it combustible. Nitrogen gas is cheap and widely available. However, it cannot achieve the particle speeds that helium can

Overspray

Overspray is the small amount of feedstock not deposited on the substrate. Cold spray technology achieves tightly focused particle spray paths, which minimizes the overspray.

Oxidation

This is the chemical reaction on the metal’s surface that occurs at high temperatures. Cold spray process temperatures are low enough that no oxidation of metal occurs in the deposition process, leading to minor to no oxide contamination in the coating

Plastic Deformation

Plastic deformation occurs when a metal particle changes shape due to applied stress, pressure, heat, or force. These forces break atomic bonds, and the deformation is permanent.

Porosity

Porosity is also known as the amount of void space in a material, usually below 1% for cold spray coatings.

Process Gas

The process gas provides the driving force for accelerating the metal powders. The process gas is heated before being blended with the carrier gas and injected into the De Laval nozzle

Recrystallization

Recrystallization is the new grain formation within the metal, often occurring to replace highly deformed (strained) grains. Dynamic recrystallization during the cold spray process can result in nanograin formation, which resists dislocation movement (high strength).

Substrate

The substrate is the base material to which the coating is applied

Thermal Barrier

Thermal barrier coatings are often applied to metal surfaces operating at elevated temperature levels. Often used for aero-tech components, thermal barriers allow for prolonged exposure to extreme temperatures and assist in extending part life by reducing exposure and risk of oxidation.

Thermal Dissipation

Also known as heat transfer, thermal dissipation occurs when heat energy moves from a high temperature object into a lower temperature object which changes the thermal energy of both materials involved in the transfer.

Wear

Wear refers to the loss of material from a component surface due to some mechanical action such as erosion, abrasion, or fatigue.