Effect of surfactant and particle size on thickness and hardness of nanocomposite coating Sn/Ag for bus duct conductor

Abstract

Bus duct conductor is one of the key components under “Bus-Way-System”. Tin plated copper is the currently used material, but improvement is needed to reduce heat generation due to contact resistance and increase efficiency. In this study, silver nanoparticles (AgNP) of size 10 nm or 100 nm were ultrasonically dispersed in deionized water with the addition of sodium dodecyl sulfate (SDS) or cetyltrimethylammonium bromide (CTAB). The dispersed solution was then mixed with commercial stannous tin plating solution and nanocomposite AgNP/Sn coating were plated on copper substrate via ultrasonic assisted electroplating. Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX) and Knoop microhardness tester were used to study the effect of AgNP size and surfactant on the nanocomposite coating. From SEM cross section images, nanocomposite with 10 nm AgNP appeared denser than that of coating with 100 nm AgNP possibly due to smaller size particles are easier to be co-deposited. For addition of 10 nm AgNP, the thickness increased from 13.82 µm to 21.77 µm (without surfactant), 19.73 µm (with SDS), and 17.64 µm (with CTAB). As for Knoop Hardness (HK0.01), the value increased from 18.5 to 44.80 (without surfactant), 41.82 (with SDS) and 21.92 (with CTAB). It seems that SDS is better surfactant than CTAB for electroplating of AgNP/Sn coating due to higher hardness of coating. The results show successful fabrication of nanocomposite Sn/Ag coating with improvement in hardness compared to Sn coating, and thickness of coating is more than the thickness required for bus duct conductor, i.e more than 3 µm.