Cold spray fundamentals

Cold spray is a cutting-edge technology for surface coatings, component repair, and additive manufacturing, particularly suited for metallic materials. Using a stream of compressed gases like nitrogen or helium it propels input powder particles at supersonic speeds onto a substrate to create uniform, dense, strongly bonded deposits without melting the material. This solid-state process minimizes all thermal effects and suppresses undesired phenomena typically occurring in thermal spray or laser-based additive manufacturing processes.

Owing to its advantages, cold spray technology is rapidly being embraced across industries such as aerospace, automotive, defense, energy, marine, and medical. Its versatility allows e.g. applying wear-resistant, corrosion-resistant, and functional coatings; repairing worn or damaged components to extend their service life; and additive manufacturing to build or redesign complex parts layer-by-layer.

More about cold spray

Cold spray technology is often ranked as one of the high-temperature thermal spray methods. However, as opposed to its generation-older counterparts, it does not use melting to process the materials. Instead, it works by propelling micron-sized metal particles to supersonic high speeds using compressed gases such as nitrogen or helium, delivered through a specially designed convergent-divergent nozzle.

Upon colliding with a component surface, the particles undergo intense plastic deformation at extreme strain rates, allowing them to bond tightly without melting. This solid-state bonding process results in dense, strong deposits, while effectively avoiding many detrimental phenomena encountered in the high-temperature thermal spray or laser-based additive manufacturing methods.

Because cold spray operates at relatively low temperatures compared to traditional thermal spray or welding techniques, it preserves the original microstructure and properties of both the particles and the base material. This makes the technology ideally suited for coating temperature-sensitive materials such as aluminum, copper, titanium, and even polymers, without causing thermal damage, oxidation, or distortion.

The resulting coatings offer excellent adhesion, low porosity, and high hardness, enhancing wear resistance, corrosion protection, and overall durability. Additionally, this process allows for precise control of coating thickness and material placement, enabling repairs of damaged parts as well as additive manufacturing of complex shapes with minimal machining. Its ability to deposit a wide range of metals and alloys with minimal environmental impact makes cold spray a versatile and sustainable solution in industries ranging from aerospace and automotive to electronics and medical implants.

Applications

Thick protective or functional surface coatings 

Repair and dimensional restoration of damaged components 

Additive manufacturing without dimensional constraints 

Main benefits

  • solid-state deposition without melting or significant heat input
  • deposits of high density, hardness, strong mechanical bonding and compressive residual stresses enhancing lifetime and durability
  • versatility in processed materials including metals, alloys, and composites
  • very high process efficiency and high productivity with rapid deposition rates, order of magnitude higher than laser-based additive methods
  • no component thermal distortion, ability to coat temperature-sensitive materials such as titanium, copper, polymers, and composites
  • minimal surface preparation required, perfect machinability of the deposits
  • no oxidation, chemical or phase changes of the materials, negligible porosity
  • environmentally friendly, no combustion or toxic waste
  • no problems with reflective metals or blends with different melting temperatures