RF-thermal plasma assisted synthesis of metal-hybrid flakes

Abstract

Summary form only given.Multi-scale hybrid composite composed of nano-metal powders such as Ni, Ag, Si, Sn and graphene nano-flakes was fabricated by RF thermal plasma. Hemispherical nano-metal particles, size ranged from 20 to 300 nm depending on the type of metals, formed on graphene nano flakes surface were obtained by a simple process - physical mixing of raw materials in the thermal plasma zone. High-temperature RF thermal plasma enables the production of hybrid materials, which is attributed to selective evaporation of raw materials depending on the material property itself. The metal coverage ranged from 0.1 to 0.7 was achieved uniformly over the graphene nano flakes surface. There were several critical parameters for the nucleation and growth of nano-metals on graphene nano flakes such as plasma power, pressure, mixing ratio of metal and graphene nano flakes, and processing gases including plasma gas, quenching gas, carrier gas and sheath gas. Interestingly, the result from XRD indicates chemical bonding between nickel and silicon and graphene nano flakes at the interface. The hybrid material of nano-metal particles and graphene flakes is expected to be solutions for many practical issues of graphene compound such as a high electrical and thermal contact resistance between graphene nano flakes surface and a difficulty in a uniform dispersion over the volume.