The synergistic inhibition by nonionic surfactant Tw-20 and polyacrylic acid (PAAC) for pure iron in HCl solution is studied by using stable state polarization curves

polarization Resistace ( R p) and EIS.The results show that Tw-20 has marked synergism with PAAC on the inhibition of corrosion of iron in HCl solution. It is found that a small amount of Tw-20 could improve the protection efficiency of low-concentration PAAC in Fe/HCl system from 68?% to above 92?%.The synergistic inhibition mechanism of Tw-20 and polyacrylic acid is studied. It is show that Tw-20 is adsorpted on the iron-solution interface

improving the surface moisten degree of the iron and dispersibility of polyacrylic acid in the solution. The adsorption of polacrylic acid on the iron surface is thus improved and in this way

the inhibition characteristic of polacrylic acid is greatly improved.