STIMULATED DECOMPOSITION OF FE(OH)2 IN THE PRESENCE OF AVT CHEMICALS AND METALLIC SURFACES RELEVANCE TO LOW-TEMPERATURE FEEDWATER LINE CORROSION

Alkalizing agents cyclohexylamine, morpholine, and hydrazine accelerate the base-induced decomposition of Fe(OH)2 even at high pH levels by lowering the activation energy of the reaction. Efficient evolution of hydrogen is observed from Fe(OH)2 suspension in the presence of hydrazine, while weakly stimulated evolution is observed in the presence of cyclohexylamine and morpholine. ft appears that the concentration and complexing abilities of the additives critically determine the yield of hydrogen. Nickel-containing surfaces such as NiO and Monel 400dagger alloy (UNS N04400) apart from pure nickel also increase the H-2 yield from Fe(OH)2 suspensions. These observations are related to corrosion occurring in the low-temperature portion of feedwater circuits of power plants.