Sara Hany

Detection of adsorbed O2− species on CeO2 solid impregnated with Ag2+ ions during its thermal treatment under a H2 atmosphere, an EPR study

10% Ag/CeO2 solid was prepared by the impregnation method. When the solid is calcined at 400 °C, three types of Ag2+ species are formed. One of them is more thermally stable compared to the others. The adsorption on the solid of O2 or H2 molecules gives an adsorbed O2- species on the surface, detected by electron paramagnetic resonance (EPR). The mobility of oxygen in CeO2 and the nature of cations loaded on this support can be the origin of the adsorbed O2- species particularly when the solid is treated under H2 molecules.

X-Ray and Neutron Scattering Studies of the 9Ni Cryogenic Steel and its Weld Joint

To guarantee the reliability and safe operation of large-scale metallic structures exposed to cryogenic temperatures for extended periods, it is important to evaluate structural properties of the base metal as well as the welded zone in order to prevent damages that could occur. Spatially-resolved high-energy synchrotron diffraction, pulsed neutron diffraction and small-angle neutron scattering have been used to study short, intermediate and mesoscopic range order in cryogenic 9Ni steel as well as the structural changes induced by the welding. Pristine 9Ni steel appears to be a metastable Fe-Ni alloy with main bcc martensitic phase and a minority fcc austenitic phase. Welding of 9Ni steel using SMAW technique has revealed a fast intergranular nickel diffusion at high temperatures during welding originated from high nickel content in the SMAW welding alloy.

Microstructural and Mechanical Properties of 9%Ni Steels Used for the Construction of LNG Storage Tanks

The growing needs for energy combined with the will to reduce CO2 emissions lead to the increase of the demand for liquefied natural gas (LNG), which will be stably available for many decades to come. Cryogenic materials used for the manufacture of the inner tanks for LNG storage are composed of 9% Ni steel plates with excellent low-temperature toughness, great ductility and crack resistance for a high safety level. To guarantee the reliability and safe operation of large-scale metallic structures exposed to cryogenic temperatures for extended periods, it is important to evaluate structural and mechanical properties of the metal base as well as the welded zone in their own operating conditions in order to prevent damages that could occur.