Influence of Al2O3 content on microstructure, electrical conductivity and adhesion strength of cold sprayed Al-Al2O3 coatings on PEEK substrate

Abstract

Due to its low process temperature, cold spray (CS) is considered an excellent metallization method to deposit thick coatings on temperature-sensitive polymeric materials. However, in previous studies, the properties (such as electrical conductivity and adhesion strength) of the cold sprayed metallic coating on the polymeric substrate are relatively low. To address this issue, large-sized spherical Al2O3 particles were added into Al powder in different proportions (i.e. 0, 10, 20, 30, 40 wt%) to prepare dense Al-Al2O3 coatings on PEEK by CS. The effect of Al2O3 content on microstructure, deposition efficiency (DE), microhardness, electrical conductivity, and adhesion strength of Al-Al2O3 coatings was systematically studied. Results show that adding an appropriate amount of Al2O3 to the feedstock can effectively improve the Al-Al splat bonding, electrical conductivity, and adhesion strength of the prepared coating on PEEK substrate, which is attributed to the ‘in-situ tamping effect’ of spherical Al2O3 particles. Moreover, the molecular structure of the substrate was not damaged or affected after the impact of Al and Al2O3 particles during the CS process. The prepared Al-Al2O3 coating exhibits better performance and provides a novel approach for polymer metallization.