Thermal and electrochemical behavior of acidic pyrophosphate (NH₄)₂Zn(H₂P₂O₇)₂.2H₂O

A study on the acidic pyrophosphate dehydrate (NH₄)₂Zn(H₂P₂O₇)₂.2H₂O, has been reperformed in order to investigate its thermal and electrochemical behavior. The results of thermal analysis (TGA-DTA), X-ray diffraction and infrared spectra showed that (NH₄)₂Zn(H₂P₂O₇)₂.2H₂O decomposes into an amorphous phase at 460 °C, then around 910 °C, the appearance of another crystalline phase is found. X-ray diffraction and infrared spectra have shown that it is the cyclotetraphosphate Zn₂P₄O₁₂. The corrosion protection efficiency of (NH₄)₂Zn(H₂P₂O₇)₂.2H₂O using electrochemical measurements is also discussed in this paper. The satisfactory results confirm that this compound can be a good inhibitor of corrosion of mild steel in an acid medium.