Preparation and characterization of highly crystallized BaTiO3 layer on Ni nanoparticles

A uniform polycrystalline BaTiO3 layer is coated on Ni nanoparticles by an economic and effective one-step sol-precipitation method for future applications in next-generation multilayer ceramic capacitors. Using NaOH to provide strong alkaline conditions, a highly crystallized BaTiO3 layer is obtained with high efficiency. The influence of the BaTiO3 coating amount on the properties of Ni powders is examined. Transmission electron microscopy and energy-dispersive spectroscopy show that the BaTiO3 layer is continuous and uniform. X-ray photoelectron spectra of the Ba, O states show that a strong bonding was formed between the coating layer and the Ni surfaces. Through this bonding, BaTiO3 can heterogeneously nucleate and crystallize on the Ni surfaces. This polycrystalline BaTiO3 layer is very effective in protecting Ni from oxidation as well as increasing the shrinkage onset temperature of Ni nanoparticles. Moreover, these properties can be further improved by increasing the BaTiO3 coating amount. (C) 2015 The Japan Society of Applied Physics