Influence of Cold Spray Parameters on Bonding Mechanisms: A Review

Abstract

The cold spray process is governed by the impact of high velocity feedstock particles onto a substrate without melting. Hence, the bulk material properties are retained. However, it is challenging to achieve good adhesion strength. The adhesion strength depends on factors such as the cold spray process parameters, substrate conditions, coating/substrate interactions at the interface and feedstock material properties. This review examines fundamental studies concerning the adhesion mechanisms of cold spray technology and considers the effect of cold spray input parameters such as temperature, stand-off-distance, pressure, process gas, spray angle, and traverse speed of the cold spray torch on the bonding mechanism and adhesion strength. Furthermore, the effects of substrate conditions such as temperature, hardness, roughness and material on the adhesion mechanism are highlighted. The effect of feedstock properties, such as feed rate, shape and size are summarized. Understanding the effect of these parameters is necessary to obtain the optimal input parameters that enable the best interfacial properties for a range of coating/substrate material combinations. It is expected that feedstock of spherical morphology and small particle size (<15 μm) provides optimal interfacial properties when deposited onto a mirror-finished substrate surface using high pressure cold spray. Deep insights into each parameter exposes the uncovered potential of cold spray as an additive manufacturing method.

Effect of Gas Propellant Temperature on the Microstructure, Friction, and Wear Resistance of High-Pressure Cold Sprayed Zr702 Coatings on Al6061 Alloy

“…To further expand on the coating quality and inter-particle boundaries, Yu et al [71] has reported that the temperature generation along the interfacial regions of impacted Upon closer inspection of Figure 4, it can also be seen that the degree of deformation from the Zr coating to the Al interface was measured to be 56 µm. When contrasted to the findings of other CS works, the observed degree of plastic deformation observed indicates that the CS coating is indeed of high quality [63,69,70]. For example, in the work of Sun et al [63], similar findings of penetration depth were observed from CS Ti6Al4V and CoCrMo coatings on 6061-T651 Al alloy.…”

The effect of process temperature and powder composition on microstructure and mechanical characteristics of low-pressure cold spraying aluminum-based coatings

“…The higher the particle velocity during the impact, the higher the probability of forming an area of strong deformation, removing the surface oxide layer from the contact surfaces, and forming adhesive bonds [50]. The authors of many papers associate an increase in adhesive strength with an increase in particle velocity during the collision [51][52][53][54].…”

Applications and Developments of Thermal Spray Coatings for the Iron and Steel Industry

“…Coating methods are identified according to specific requirements such as desirable coating thickness; adhesion mechanism and essential mechanical strength; component geometry and chemistry; coating process conditions that are amenable to the component; and operating conditions of the coating [ 14 ]. In particular, thermal spray processes are widely proven in industries such as power generation, automotive, aerospace, marine, and petrochemical for protection and repair of components [ 15 ].…”