Interfacial metal/ceramic bonding mechanism for metallization of ceramics via cold spraying

摘要

Metallization of ceramics is drawing more and more attention in industries. The mechanisms involving high bonding strength between cold sprayed metallic coatings and ceramic substrates are not yet clear. In this study, aluminum (Al) particles and alumina (Al2O3) substrates were employed to reveal impact phenomena in cold spraying. Electron backscatter diffraction equipment (EBSD) and high-resolution transmission electron microscope (HRTEM) were used to investigate the interfacial microstructures of the Al particles and Al2O3 substrates. Computational fluid dynamics (CFD) and finite element analysis (FEA) were employed to quantitatively characterize the temperatures and plastic strains at the interfaces. The bonding strength of the Al coatings and Al2O3 substrates was measured and the analysis to the fracture morphologies was also conducted. The results show that the Al particles at the interfaces presented fine-grain and amorphous structures, and the Al2O3 substrates experienced a brittle rupture. The Al coatings bonded on the ceramic surfaces due to mechanical interlocking and heteroepitaxy. The results offer more details to understand the bonding mechanisms of metallic particles and ceramic substrates.