Here, we have introduced ferrofluid as a novel material comprising of ferromagnetic
nanoparticles as a corrosion inhibitor. Corrosion behavior of carbon steel in 1M HCl has
been studied as a function of various concentration of aqueous ferrofluid. The novel
ferrofluid has been specially synthesized to achieve the stability in acidic media when it is
mixed with HCl. This ferrofluid has been evaluated by gravimetric and polarization
measurement techniques. It was observed that the inhibition efficiency increases with
increasing ferrofluid concentration up to 1200 ppm and there after it remains constant. This
is confirmed by the decrease in corrosion rate from 2.6812 in blank to 0.2560 in 1200 ppm.
It is found that this system follows the Langmuir adsorption isotherm.