A study on the CNTs-Ag composites prepared based on spark plasma sintering and improved electroless plating assisted by ultrasonic spray atomization

Carbon nanotubes reinforced silver composites (CNTs-Ag composites) are considered as a promising candidate for high-performance contact materials with the potential properties of low contact resistance, high thermal conductivity and excellent mechanical performance. While at present the dispersion of CNTs in silver matrix and the interfacial bonding of the composites remain problems to be resolved or enhanced. In this study, silver nanoparticles coated carbon nanotubes (Ag@CNTs) were synthesized through an improved electroless plating method assisted by ultrasonic spray atomization, which inhibited excessive growth of silver particles and led to much more uniform nanometer grain-sized coating. The Ag@CNTs were solution ball-milled (SBM) with Ag powders and then were densified by spark plasma sintering (SPS). The composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). The results showed the CNTs dispersion in Ag matrix was improved benefitting from the homogeneous Ag nanoparticles distribution on CNTs, and correspondingly, the hardness and electrical conductivity were significantly improved. The mechanism may result from the combination of more homogeneous CNTs dispersion and tighter interface bonding in composite materials.