Microstructural investigations on bonding mechanisms of cold-sprayed copper with SS316L steel

Abstract

The purpose of the study was to understand the adhesion mechanism between cold-sprayed copper and SS316L steel substrate. Coatings of 3-mm thickness were deposited by coldspraying on steel substrates prepared with different roughness values. To understand the bonding mechanism of the coating with substrates, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses were done on interfacial surfaces; exposed after the adhesion testing. Additionally, cross-sectional as-well-as top surface deformation behaviour of single copper particles deposited on steel substrates was investigated by using SEM/EDS, to elucidate the mechanism behind bonding. The results of the study validated that the adhesion is governed by both metallurgical bonding, as-well-as, mechanical interlocking, owing to the jetting formation. The mirror-polished surface resulted in a better adhesion strength as compared to the as-received and semi-polished surfaces, which was further validated by ultrasonic testing. Also, smaller-sized particles were found to be favourable for good adhesion strength.

Mechanical Properties of Cold Sprayed Aluminium 2024 and 7075 Coatings for Repairs

“…The average percentages of porosity measured from 20 readings of each coating were 1.148 ± 0.614% for Al-2024 and 0.006 + 0.009 − 0.006% for Al-7075. This is in line with reports from other researchers and industrial releases on the porosity of cold-sprayed materials [6,7]. Micrographs of each representative coating are shown in Figures 7 and 8.…”

“…A mixture of mechanisms were believed to be responsible for the bonding of coatings, mainly mechanical interlocking and metallurgical bonding due to adiabatic shear instability at powder particle-substrate interface [3][4][5]. Recent reports have been made on the investigation into the roles of mechanical interlocking and adiabatic shear instability in cold spray bonding mechanisms, and has presented contradictory hypotheses which will require further investigations [6][7][8]. The amount of interfacial bonded material sprayed at varying angles was also investigated and found to decrease with increasing spray angles [9].…”

Enhanced mechanical properties of molybdenum-coated aluminium via laser cladding

“…Therefore, the HVOF coating presents a lamellar structure with a lot of pores, cracks and unmelted particles, as illustrated in Figure 6(a). Furthermore, the bonding between the coating and substrate is related to severe plastic deformation during the impacting process [22,23]. Thus atomic diffusion is limited at the coating interfacial region, which leads to the formation of a mechanical bonding interface.…”

Effects of Different Post-Treatments on Arc Erosion Resistance of Cold-Sprayed AgC Composite Electric Contact

“…During this process, powder materials impact the substrate at an ultra-high speed and form a homogenous coating by plastic deformation. The whole process is conducted at near room temperature, thus it can fabricate versatile elements or alloy coatings with negligible oxidation [10,11]. Furthermore, due to the high speed of the powders, the coating presents uniform components and strong adhesion with substrates [12,13].…”