Study On The Pyrazolone And Azole Corrosion Inhibition For Copper In NaHCO3 Medium

In this paper, six types of compounds have been synthesized, including three pyrazolone compounds of PAS,POTAS and PDTAS, two trazole containing pyrazolone compounds of PFAT and PAAT and one tetrazole compound of APPT. Their corrosion inhibition for copper in 5%NaHCO3 solution was studied by gravimetric measurements, potentio-dynamic polarization curves and electrochemical impedance. The paper has two parts: review section and experimental section.In review section ,the definition and the development of corrosion inhibitors are presented in this paper. we introduced the kinds of corrosion inhibitor, corrosion mechanism and measurements detecting performance of inhibition.In experimental section, the three pyrazolone compounds of PAS,POTAS and PDTAS, two trazole containing pyrazolone compounds of PFAT and PAAT and one tetrazole compound of APPT were synthesized. Their structures were characterized by IR spectrum. Their corrosion inhibition for copper in 5%NaHCO3 solution was studied by gravimetric measurements, potentio-dynamic polarization curves and electrochemical impedance spectroscopy(EIS). The corrosion kinetics and the effect of temperature on inhibition efficiency were also investigated. Their adsorption actions on the surface of copper and inhibition mechanism were discussed simply. We made some conclusions through experiment:(1) The six compounds had good performed for copper in 5%NaHCO3 solution. The results of experiment revealed that the efficiency of these compounds have increased with the increase of concentration, but the inhibition efficiency of these compounds reached maximum value at some concentration.(2) The result of potentiodynamic polarization showed that these compounds inhibited both anode and cathode corrosion reactions. These compounds of POTAS,PDTAS,PFAT and PAAT were mixed type inhibitors. But PAS and APPT inhibited mainly anode corrosion reactions and they were anodic type inhibitors. (3) The Nyquist plots from the impedance spectroscopy were good semicircles. This showed that the corrosion of copper in 5%NaHCO3 solution was controlled by transfer charge. The calculated values of corrosion efficiency were good agreement with polarization curves and weight loss measurements.(4) We have studied the relationship between temperature and inhibition efficiency of these compounds. The results showed that these compounds of PAS,POTAS,PDTAS,PFAT,PAAT and APPT had good inhibition efficiency in the temperature range researched, but the inhibition efficiency of these compounds was decreased with the crease of temperature.(5) The behavior of adsorption of these compounds on the copper surface has been discussed elementarily. The adsorbent isotherm of these compounds on the copper surface has been calculated.(6) The obtained values ofâ–³Gm showed adsorptions of these compounds on the copper surface were spontaneous. It also indicated that these compounds were physical adsorption on the copper surface.