Design and micro mechanical properties of nano-SiO2 strengthened composite coatings towards remanufacturing

Nano-SiO₂ particles strengthened Ni-based composite coating was designed and prepared on steel substrate. The structures and nanoparticle content of the nano-SiO₂/Ni composite coating were determined by SEM, EDS and TEM; and the micro mechanical properties were tested by nano-indentation technique. The results show that 56% of particles in the solution are dispersed in size of less than 100 nm, the content of nanoparticles co-deposited in the coating doubles and structure of the coating is more compact and uniform than that of Ni coating. Nano-SiO₂/Ni coating exhibits excellent micro mechanical properties, and the nanohardness and elastic modulus are 7.81 GPa and 198 GPa, respectively, which are attributed to finer crystal strengthening, dispersion strengthening and high-density dislocation strengthening of nano-SiO₂ particles to the composite coatings. Foundation item: Project (50235030) supported by the National Natural Science Foundation of China; Project (G1999065009) supported by the National Basic Research Program of China