SYNTHESIS OF CARBON NANOTUBES ON STAINLESS STEEL 304 SUBSTRATES BY THERMAL CVD METHOD: EFFECT OF HCL SURFACE ETCHING ON CNT GROWTH

Abstract

Multi-walled carbon nanotubes were directly grown by thermal chemical vapor deposition on as received and hydrogen chloride treated Stainless Steel 304 substrates without application of an external catalyst. To study effect of hydrogen chloride etching on growth of CNTs, three samples were used with different variations in etching and they were (1) SS 304 substrate dipped and sonicated in concentrated hydrogen chloride for 10 minutes. (2) SS 304 substrate only dipped in concentrated hydrogen chloride for 10 minutes. (3) SS 304 substrate as received untreated with hydrogen chloride. Synthesis of CNTs was carried out in a thermal chemical vapor deposition set up with growth temperature of 800 °C and C2H2 as carbon carrier gas. Scanning electron microscopy observations suggests that carbon nanotubes were there in each substrate but CNTs coverage density and CNTs diameter was different. Untreated SS 304 substrate shows maximum CNTs coverage density and minimum CNTs diameter. Hydrogen chloride sonicated SS 304 substrate shows more amorphous carbon and less CNTs.