Synchrotron XRD Analysis of Local Positions in Laminated Heavy Rust Layer Formed on Weathering Steel Bridge

Abstract

The detail structure of heavy rust layers with large swelling and laminated layers formed on weathering steel bridges have been investigated by optical microscope and laboratory powder X Ray diffraction (XRD) and synchrotron XRD in SPring 8. Some large gaps (inter layer) and many linearly arrayed voids (LAV) were found along layers. The mass ratio of spinel type iron oxide [mainly Magnetite (Fe 3 O 4 )] in average composition of the whole layer was 30 40 mass. In contrast the mass ratio of spinel in its local parts, i.e. outer layer, inter layer and inner layer position was not higher in common but mass ratio of b FeOOH was higher. Thus we propose a multilayer model structure for these unique rust layers which are made of Spinel Poor, Rich and Poor unit cell structure (SPRaP cell) compartmentalized by LAV.

Atmospheric corrosion of mild steel in chloride-rich environments. Questions to be answered

“…In severe marine atmospheres, in conditions with a high chloride content and long moisture retention times (edges of plates, boxed locations, etc. ), it is common to see the formation of coarse flakes and layered sheets . After long exposure times it is sometimes also possible to see the formation of rust mounds , which we have only found in the severe marine atmosphere of Cabo Negro (Asturias, Spain), with an average annual salinity of 150 mg chloride/m 2 day .…”

“…Figure presents these two singular types of rust formations. The formation of sheet‐type rust has been reported in the literature . Reference to the formation of rust mounds has only been found in the paper of Raman .…”

“…Using conventional XRD and synchrotron XRD, Hara et al found high magnetite and goethite contents, 40% and 38%, respectively, in heavy rust layers with large swellings and laminated layers, along with considerable akaganeite contents (16%) and a very low lepidocrocite content. These researchers noted the presence of large interlayer gaps between the outer and inner layers, as well as many linearly arrayed voids (LAV) and cracks.…”

Frequency‐dependent attenuation and velocity characteristics of nano‐to‐micro scale, lossy, magnetite‐rich materials

“…Also of interest are the magnetically lossy corrosion products associated with the rusting of steel pipes, construction fittings and concrete reinforcing bars. This field of study has seen some important recent advances in our understanding of ‘rust’ (Gismelseed et al ; Duffo et al ; Zitrou et al ; Hara et al ) and the volumetric expansion and cracking of concrete casings/claddings associated with corroding steel products (Bhargava et al ). The studies show that nano‐and micro‐scale magnetite (Fe 3 O 4 ) is a significant component of the corrosion materials along with lepidocrocite (gamma‐FeOOH), akaganeite (beta‐FeOOH) and goethite (alpha‐FeOOH).…”

X-ray Diffraction Analysis of Rust Layer on a Weathering Steel Bridge with Surface Treatment Using Synchrotron Radiation

“…24) The diffraction intensities were obtained by integrating subdivided diffraction intensities in each 0.01 2-step of diffraction peaks of -FeOOH/9. À14:70 (220), after removing the background of the XRD pattern using Sonneveld-Visser method.…”