Effect of gamma-irradiation on the properties of aluminum dihydrogen triphosphate

The effect of gamma irradiation on the properties of aluminum dihydrogen triphosphate (ADTP) in the dose range of 0 to 150 kGy was studied by X-ray diffraction (XRD) analysis, thermal analysis, acid–base titration, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Although the XRD and SEM results indicated that there were no significant effects on the crystal structure and the surface morphology of ADTP, thermal analysis revealed that the crystal transition of Al(PO3)3 from Type-B to Type-A did not occur at a high temperature in irradiated ADTP. EIS results showed that high-dose gamma irradiation (100 kGy and 150 kGy, 60Co) improved the corrosion inhibition ability of ADTP on tinplate steel. SEM was used to investigate the surface of tinplate steel panels after immersion in ADTP extracts for 69 h, and revealed that many slices were formed on the surface. The slices were attributed to the formation of Fe2P3O10. Inter-slice gaps may be the reason for the lower corrosion resistance of ADTP compared with the resistance of some toxic pigments containing lead and chromium. Overall, high doses of gamma irradiation improved the corrosion resistance of ADTP