Investigation On Vapor Phase Inhibitor Of Phytic Acid

The atmospheric corrosion can cause the degradation or failure of material, which not only bring enormous expense to national economy, but also make grievous effect on daily life and production. In order to decrease the corrosion of metal, many methods have been used to protect the metal, and vapor phase inhibitor is one of the better ways. However, with the increase of global environmental deterioration, more and more people pay attention to the development and use of chemicals, as well as the corrosion inhibitors. Therefore, the developing of environmentally friendly inhibitors has become the trend of scholars in the world. Because the evaluation method of the vapor phase inhibitor is still imperfect, the study of evaluation method also becomes the hot point.In this paper, a new type of environmentally friendly volatile corrosion inhibitor for carbon steel was prepared by extracting phytic acid from rice bran using dilute acid. Its inhibiting behavior on carbon steel in 3% brine was investigated by means of weight loss and electrochemical methods, as along with the inhibition mechanism.According to the characteristics of vapor phase inhibitors, the production processes of phytic acid can be simplified and improved, which can reduce production costs, meanwhile increase its inhibitor performence.Weight loss experiments show that the vapor phase inhibitor which extracts by the method mentioned exhibits good corrosion-inhibition effect for carbon-steel in 3% brine and inhibition efficiency can reach 90%,which is superior to commercial phytic acid. The results of linear polarization curve indicate that the way of using atmospheric corrosion monitoring (ACM) electrode can identify the vapor corrosion inhibitor of phytic acid quickly and simply.The testing data of polarization curve indicate that the extractive phytic acid mainly inhibits the anodic process of corrosion.In the Nyquist plots of Q235 steel with inhibitor, there are two capacitive loops at high frequency and one diffusion line at low frequency, exhibits the characteristic of Warburg impedance. The capacitive loop at high frequency part means the film covering the anode, and the line at low frequency part means the diffusion-controlled reaction, representing the ferric ion diffusing from inside to outside of corrosion inhibitor film brings the Warburg impedance.