Cold Spray technology allows materials to be constructed layer upon layer.

Cold spray technology

Cold gas-dynamic spray technology, or Cold Spray technology, is a rapidly emerging industrial coatings technology.

• 12 December 2007 | Updated 14 October 2011

• The problem
• What CSIRO is doing
• How it works
• Outcomes
• Applications

CSIRO is developing novel applications for Cold Spray technology.

The problem

Conventional thermal spray processes preheat the material to be sprayed.

This means it reaches the object being coated in a semi-molten state and splashes across the surface.

As these ‘splats’ cool, they contract slightly, creating stresses or flaws at the interface and within the coating that can cause defects later.

What CSIRO is doing

CSIRO has established a well-equipped Cold Spray laboratory and is providing Australian industry with leading-edge applications of this technology.

Prior to its introduction into the production process, CSIRO tailors the technology for each application.

Each application may require research such as:

• identifying the best materials
• determining the best particle sizes
• discovering the best impact velocities
• examining gas dynamics
• investigating plastic deformation
• determining the appropriate spray nozzle configurations.

Our Cold Spray team has extensive experience with a variety of surface science and engineering technologies and has developed and commercialised technologies to extend tooling life.

How it works

Cold Spray materials typically:

• remain at or near room temperature until impact
• slam into the substrate at supersonic speeds (500-1 500 metres per second)
•  form a metallurgical bond
• do not undergo undesirable chemical changes and stresses.

Researchers believe the high velocity impact disrupts thin oxide films on the surface of the particles and substrate. This means their atomic structures come into intimate contact under momentarily high interfacial pressures.

Advantages of Cold Spray include:

• retaining initial properties of particles
• depositing oxygen-sensitive materials without vacuum
• low oxide content
• high density
• high thermal and electrical conductivity
• high hardness and cold work microstructure
• creating corrosion-resistant coatings
• depositing plastic coatings without the need for volatile solvents
• intermetallic coatings or repair (phase and compositional stability)
• depositing metal on ceramic or metal on glass
• ability to perform rapid prototyping.

Outcomes

This technology offers the opportunity for:

• direct fabrication of low-defect parts
• repairing defective areas without changing the structure
• joining chemically dissimilar materials with bonds that gradually transition from one material to the other
• a low-temperature alternative to welding
• building a composite component using different materials in different locations
• rapid prototyping.

Applications

Any industry using thermal spray systems could likely use Cold Spray technology.

Examples include:

• biomedical – prostheses with improved wear
• aerospace – fatigue-resistant coatings
• chemical – improved corrosion resistance
• mineral processing – improved corrosion and erosion resistance
• die casting – extending die life
• electronics – creating a heat sink or superconductive, magnestostrictive surfaces
• printing – copper coating on rollers
• oil and gas – improved corrosion resistance
• glass – platinum coating.

Read more about CSIRO's research into Machinery, Processes & Systems.