Synergistic effect of gamma-ray irradiation and calcium oxide on corrosion inhibition of aluminum dihydric tripolyphosphate on mild steel

Aluminum dihydric tripolyphosphate (ADTP) was irradiated by using a Co-60 gamma-ray source and a maximum dose up to 150 kGy, subsequently recombined with calcium oxide (CaO) by co-grinding, and the synergistic effects of gamma-ray irradiation and CaO on the anticorrosive performance of irradiated-ADTP on mild steel were studied. The efficiency of irradiated-ADTP and irradiated-ADTP/CaO as corrosion inhibitors for mild steel boards in 3.5% NaCl solution was determined by means of weight-loss determination, Tafel polarization and electrochemical impedance spectroscopy (EIS). The morphology of the irradiated-ADTP particles was observed by scanning electron microscopy (SEM). Results showed that irradiated-ADTP/CaO had good inhibiting properties for steel corrosion in the solution, with an efficiency of around 95% at gamma-ray absorbed dose of 150 kGy. But, the inhibiting efficiency of irradiated-ADTP in the absence of CaO decreased with the dose. The positive effect of the combination of gamma-ray irradiation and CaO was mainly attributed to the loosening lamellar structure of ADTP caused by gamma irradiation, which facilitated the neutralization reaction between ADTP and CaO.