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 certa in organic compounds of the tetrazole type was tested using electroche mical and gravimetric methods. The results obtained have shown that th e dissolution rate of the steel depends on the molecular structure and on the concentration of the product. The comparison of inhibiting eff iciencies shows that 1-phenyl-5-mercapto-1,2,3,4-tetrazole (PMT) is th e best inhibitor of the tested tetrazole series. The inhibition mechan ism and the parameters influencing the inhibiting efficiency of PMT ar e examined.