Synthesis of smooth low friction graphitic nanoparticle film by vacuum arc deposition

Abstract

Formation of smooth low friction carbon onion nanoparticle film was carried out using vacuum arc deposition. Carbon onions were synthesized by the arc discharge of carbon rod as a cathode and deposited directly onto the substrate in a vacuum. The process of carbon onion synthesis and nanoparticle film growth was investigated using transmission electron microscopy (TEM), atomic force microscopy (AFM), and quadrupole mass spectrometer (QMS). It was observed that isolated carbon onions were successfully synthesized by pulsed arc discharge of the carbon rod as a cathode under relatively low pressure of 10−7 Pa. The synthesized isolated carbon onions around the cathode were in flight in vacuum and deposited onto the substrate. A smooth carbon onion nanoparticle film with surface roughness (Ra) of 0.37 nm was gradually formed on a graphite substrate by 100 pulse shots of the arc discharge. A smooth nanoparticle film was achieved due to the mixture of the deposition of carbon onions and amorphous carbon in this process, where amorphous carbons were filled between carbon onions interparticle. AFM friction measurements in the vacuum revealed that the synthesized nanoparticle film possessed lower friction coefficient than graphite, which was attributed to the low adhesive force and smooth surface roughness of the carbon onion nanoparticle film.