Corrosion behavior of brass in SCW-SDBS-TiO2 nanofluid

Abstract

A stable TiO2 nanofluid with absolute value of Zeta potential greater than 44 mV was prepared by using sodium dodecylbenzene sulfonate (SDBS) as a dispersing agent in this paper. Electrochemical methods and surface analysis were used to study the corrosion behavior of brass in simulated cooling water (SCW), simulated cooling water containing SDSB (SCW-SDBS), and TiO2 nanofluid (SCW-SDBS-TiO2 nanofluid). The results show that the total resistance Rsum of the brass electrode was smallest and increased slowly with time, and the corrosion current density was largest in SCW. The corrosion products on the brass surface were composed of the inner layer of Cu2O and the outer layer of Zn5(CO3)2(OH)6. In SCW-SDBS medium, the Rsum value of brass increased rapidly in the first 4 days and was significantly higher than that in SCW. A protective adsorption SDBS film was formed on the brass surface and minimized the corrosion rate of brass in SCW-SDBS medium. In SCW-SDBS-TiO2 nanofluid, the Rsum value of brass was higher than that in SCW, but significantly lower than that in SCW-SDBS medium. There was almost no SDBS adsorption film formed on the brass surface in SCW-SDBS-TiO2 nanofluid, which significantly reduced the corrosion inhibition performance of SDBS on brass. The competitive adsorption of negatively charged TiO2 nanoparticles and SDBS anions in the nanofluid on the brass surface might be the reason why the protective SDBS adsorption film was not easy to form on the brass surface in SCW-SDBS-TiO2 nanofluid.