The Effect Of Two Kinds Of Inorganic Corrision Inhibition And SDBS Complex Solution On The 304 Stainless Steel

In this work, we made a research on the inhibition effect of sodium tungstate?sodium dodecyl benzene sulfonate (SDBS) and their mixtures on 304 stainless steel in sodium chloride medium by electrochemical polarization curve method. The inhibition effect of complex inhibitor was also investigated by EIS and XPS method. The size of small pores were finally observed by scanning electron microscope. The results are as follows:(1)The Organic corrosion inhibitor SDBS and inorganic corrosion inhibitor Na2WO4 and NaNO2 belong to the anodic inhibitor, the three inhitors can all suppress the anode reaction so that the corrosion potential E?can move to the positive direction. The 304 stainless steel can form a stable passivation pitting potential Eb in basic solution of 0.585 g·L-1 NaCl. When The Organic and inorganic corrosion inhibitors of SDBS/Na2WO4/NaNO2 were added alone in the bassic solution, they all did not affect the existence of the stable potential Eb and the passivation regions of the 304 stainless steel. when the three inhibitors were used alone in the bassic solution, all of them could increase Eh of the 304 stainless steel, and could decrease passive current density.(2)We investigated the influence of concentration of corrision inhibitors, when the corrision inhibitor was used alone.When 0.1 g·L-1 SDBS was used, the 304 stainless steel showed highest pitting corrision potential, and the current density was smallest at the initial reaction process. When 0.4 g·L-1 Na2WO4 was used, the 304 stainless steel showed highest pitting corrision potential. The 304 stainless steel also exhibited highest pitting potential when 0.2 g·L-1 NaNO2was used alone, when further increasing the concentration of NaNO2to 0.4g·L-1, the pitting corrision inhibition effect on 304 stainless steel did not increase.(3)When 0.2 g·L-1 Na2WO4and 0.02 g·L-1 SDBS complex solution was used in basic solution of 0.585 g·L-1 NaCl, the stainless steel showed good synergistic inhibition effect. While high concentration of Na2WO4 and SDBS complex solution was used, the stainless steel did not show obvious synergistic inhibition effect. For the pitting corrision effect of 304 stainless steel, by keeping the soaking time constant,0.2 g·L-1 Na2WO4and 0.02 g·L-1 SDBS complex solution were added to basic sulution, leading to better stability than basic sulution was not added, the steel still showed excellent corrosion inhibition effect after 24 hours.(4)0.4 g·L-1 NaNO2 and 0.1 g·L-1 SDBS complex in 0.585 g·L-1 NaCl solution showed good synergistic inhibition effect on 304 stainless steel. When the concentration of NaNO2 was low, synergistic inhibition effect did not appear. For the pitting corrision effect of 304 stainless steel, by keeping the soaking time constant,0.4 g·L-1 NaNO2 and 0.1g·L-1 SDBS complex solution in basic solution showed better stability than the inhibiton solution of 0.1 g·L-1 SDBS/0.4 g·L-1 NaNO2 was used alone.