Evaluation of Parameters for Assessment of Inter-Splat Bond Strength in Cold-Sprayed Coatings

Abstract

The quality and performance of cold spray coatings are largely determined by the extent and strength of bonding between the adjacent splats. Usually, the extent of inter-splat bonding is only qualitatively estimated by examining the polished and etched sectioned surfaces of the coated sample. Thus, there is a clear need for indirect techniques to quantitatively estimate the extent of inter-splat bonding so that they can serve as quality control tools. In this study, elastic modulus, electrical conductivity, and critical load for inter-splat debonding as determined using a scratch test are considered as possible parameters for the estimation of the extent of inter-splat bonding using four different cold spray coatings (Ag, Cu, 316 Stainless Steel, and Zn) as model coatings. It is demonstrated that all the three parameters are capable of quantifying the extent of inter-splat bonding.

The influence of process parameters and heat treatment on the properties of cold sprayed silver coatings

“…9a and 10). The above postulate is also supported by an earlier work [34] wherein the critical load for inter-splat debonding measured using scratch test was nearly 3½ times higher in the Ag coating as compared to Cu coating in the as coated condition.…”

Microstructure and mechanical properties of cold sprayed 7075 deposition during non-isothermal annealing

“…This is in good agreement with previous studies [37][38][39][67][68][69][70] that showed annealing at high temperatures can recover the loss of ductility in the deposited materials by reducing the porosity in the microstructure.…”

“…2a shows an elongated void located at a particle/particle boundary. It is important to note that although the coating quality is good, even limited porosity can have a detrimental effect on the final mechanical properties of CSP depositions [35][36][37][38][39]. This topic will be discussed further in Section 3.4.4.…”

Processing-structure-property relationships in electron beam physical vapor deposited yttria stabilized zirconia coatings

“…35 Since the YSZ coatings exhibit inclined columnar structure under certain conditions depending on the VIA, the scratch test was performed in two opposite directions, and the average L c values have been reported. A scanning electron microscope ͑SEM, S-4300SE/N, Hitachi, Japan͒ was used for examining the surface morphology and the crosssectional microstructures.…”