WHAT IS COLD SPRAY?
The Process; Cold spray, Gas dynamic cold spray, supersonic particle deposition, is a high-energy solid-state coating and powder consolidation process. Cold spray uses an electrically heated high-pressure carrier gas, (like nitrogen or helium), to accelerate metal powders through a supersonic nozzle. The powder then forms a coating or free-standing component (Additive Manufacturing).
The bonding mechanism of cold spray is a combination of mechanical interlocking and metallurgical bonding from re-crystallization at highly strained particle interfaces.
Cold gas spraying is the most recent method in the field of thermal spraying. Compared with conventional thermal spray processes, cold gas spraying offers special advantages, as the spraying material is neither fused nor melted during the process, so the effect of heat on the coating and the substrate material is very low.
The high kinetic energy of the particles and the high degree of deformation during the impact on the substrate that is connected with it, allows the manufacturing of homogenous and very dense coatings. The range of coating thicknesses varies from 100 micron up to 5 centimeters or more.
Metallic coatings are the main product. The coatings have physical and chemical properties similar to the properties of the base material.
The spray powders are injected into the nozzle with a powder feeder and carrier gas, and are accelerated to a particle speed of up to 1200 m/s in the main gas stream.
In the highly focused spray jet particles impinge the - in most cases no special surface preparation - surface of the component, deform the particles and form a strongly adhesive/cohesive and low-oxide coating.
Cold Spray can create mixtures of metallic / nonmetallic materials to form a coating or free-standing structure.
Some Cold Spray Applications:
Characteristics of Cold Spray
Cold spray is an efficient method for the application of Metals, Metal Alloys, and Metal blends for numerous applications: