Oxide Film Properties of Ni-Cr-Fe Alloys with Different Iron Content in High Temperature Water Environment

Oxide film properties of Ni-Cr-Fe alloys with different iron content in simulated PWR primary water environment with different water chemistry conditions were investigated by scan electron microscopy (SEM) and transmission electron microscopy (TEM). After 978 h of immersion in the high temperature water environment with 2.6 mg/L disolved hydrogen at 310 ℃, the resuts show that increasing the iron content in the alloys promoted the formation of the spinel oxide in the outer oxide layer and the growgh of local oxidation penetrations into the alloy matrix along the interface between the inner layer and alloy matrix. After 1 012 h of immersion in the high temperature water environment with 8 mg/L disolved oxydrogen at 310 ℃, the resuts show that increasing the iron content in the alloy promoted the formation of spinel needle-like oxides and decreased the amount of atactic NiO particles in the outer layer, besides, increased the thickness and porous area in the inner layer.