Corrosion inhibition of a carbon steel in 2M H3PO4 medium by "tetrazole"-type organic compounds

The inhibiting effect of steel corrosion in a 2M H3PO4 medium by certain organic compounds of the tetrazole type was tested using electrochemical and gravimetric methods. The results obtained have shown that the dissolution rate of the steel depends on the molecular structure and on the concentration of the product. The comparison of inhibiting efficiencies shows that 1-phenyl-5-mercapto-1,2,3,4-tetrazole (PMT) is the best inhibitor of the tested tetrazole series. The inhibition mechanism and the parameters influencing the inhibiting efficiency of PMT are examined.