Preparation of metal–ceramic composites by sonochemical synthesis of metallic nano-particles and in-situ decoration on ceramic powders

•One-pot metal nanoparticle synthesis and decoration on several ceramic powders.•Preparation of high-load metal–ceramic composites.•Different parameters were examined.•The metal nanoparticles mainly spherical and partly form dendritic agglomerates.•Spark Plasma Sintering of the composite powders led to dense metal–ceramic bodies. Copper and nickel nanoparticles were synthesized using reducing agents in the presence of direct high energy ultra-sonication. The metallic nanoparticles were decorated on various ceramic substrates (e.g. α-Al2O3, and TiO2) leading to metal reinforced ceramics with up to 45% metallic content. Different parameters, such as the amount of precursor material or the substrate, as well as the intensity of ultrasound were examined, in order to evaluate the percentage of final metallic decoration on the composite materials. All products were characterized by means of Inductively Coupled Plasma Spectroscopy in order to investigate the loading with metallic particles. X-ray Diffraction and Scanning Electron Microscopy were also used for further sample characterization. Selected samples were examined using Transmission Electron Microscopy, while finally, some of the powders synthesized, were densified by means of Spark Plasma Sintering, followed by a SEM/EDX examination and an estimation of their porosity.