Abnormal Microstructure Evolution Behaviors of Annealed Ag-Co Alloy Film on Flexible Polyimide Substrates

Ag-Co alloy films were deposited on polyimide by magnetron sputtering. XRD, HRTEM and FESEM were used to characterize phase and surface morphology of Ag-Co alloy films. Surprisingly, the results showed that a large amount of polyhedral single crystal Ag nanoparticles were self-grown on the surface of Ag-Co alloy films, which is significantly different from the microstructure of Ag-Co alloy film on rigid substrates. Moreover, the average number and size of Ag particles are dependent on annealing temperature. These analysis results indicated that Co inhibits the growth of Ag grains and leads to the formation of Ag particles on the surface of the film. These nano-sized Ag particles and Ag-Co films are assembled into a new type of particles/ films with a convex structure.