Microstructure and deuterium permeation resistance of the oxide scale prepared by initial oxidation method on vacuum solar receiver

Deuterium permeation resistant scales on vacuum solar receiver were developed by initial oxidation method. The initial oxidation atmosphere was produced by the H2–H2O mixtures at 827 °C, with a low oxygen partial pressure of about 10− 19 Pa. The phases and morphologies of the oxide scales were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), X photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The formation of an oxide scale was observed with an inner layer essentially composed of chromium oxide and an outer layer mainly consisting of Mn1.5Cr1.5O4 spinels. The deuterium permeation of 316L stainless steel coated with Cr2O3 scale was only 1/80 of that of uncoated 316L stainless steel under loading of 80 KPa at 600 °C. The chromium oxide developed on the surface of 316L stainless steel revealed a marked inhibiting effect on the permeability of the deuterium and the associated mechanisms were discussed.