John Shirokoff

Electrochemical and Microstructural Analysis of FeS Films from Acidic Chemical Bath at Varying Temperatures, pH, and Immersion Time

The corrosion resistance and corrosion products of 4130 alloy steel have been investigated by depositing thin films of iron sulfide synthesized from an acidic chemical bath. Tests were conducted at varying temperatures (25°C–75°C), pH levels (2–4), and immersion time (24–72 hours). The corrosion behavior was monitored by linear polarization resistance (LPR) method. X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) spectroscopy, and Scanning Electron Microscopy (SEM) have been applied to characterize the corrosion products. The results show that, along with the formation of an iron sulfide protective film on the alloy surface, increasing temperature, increasing immersion time, and decreasing pH all directly increase the corrosion rate of steel in the tested experimental conditions. It was also concluded that increasing temperature causes an initial increase of the corrosion rate followed by a large decrease due to transformation of the iron sulfide crystalline structure.

Structural and elastic characterization of Cu-implanted SiO2 films on Si(100) substrates

B.J. and M.C.R. are grateful for financial support from nthe Australian Synchrotron Research Program, funded by the nCommonwealth of Australia. M.C.R. would also like to nthank the Australian Research Council for their financial support. The financial support of the Natural Sciences and Engineering nResearch Council of Canada NSERC is gratefully nacknowledged by G.T.A. and J.S.

Effect of Elemental Sulfur and Sulfide on the Corrosion Behavior of Cr-Mo Low Alloy Steel for Tubing and Tubular Components in Oil and Gas Industry

The chemical degradation of alloy components in sulfur-containing environments is a major concern in oil and gas production. This paper discusses the effect of elemental sulfur and its simplest anion, sulfide, on the corrosion of Cr-Mo alloy steel at pH 2 and 5 during 10, 20 and 30 h immersion in two different solutions. 4130 Cr-Mo alloy steel is widely used as tubing and tubular components in sour services. According to the previous research in aqueous conditions, contact of solid sulfur with alloy steel can initiate catastrophic corrosion problems. The corrosion behavior was monitored by the potentiodynamic polarization technique during the experiments. Energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) have been applied to characterize the corrosion product layers after each experiment. The results show that under the same experimental conditions, the corrosion resistance of Cr-Mo alloy in the presence of elemental sulfur is significantly lower than its resistance in the presence of sulfide ions.

Mobile harbor crane wheel hub fatigue failure

Failure analysis of a mobile harbor crane wheel hub demonstrated that the mechanism of failure was fatigue. The wheel hub was a ductile cast iron component that had been subjected to cyclic loading during a ten-year service period. The fracture surface of the fatigue failure also contained corrosion deposit, suggesting that cracking occurred over a period of time sufficient to allow corrosion of the cracked surfaces. Replacement and alignment of the failed wheel hub is recommended along with inspection of the nonfailed wheel hubs that remain on the crane.

Corrosion Behavior of Cr-Mo Alloy Steel in Direct Contact with Elemental Sulfur

The chemical degradation of stainless steel components in sulfur-containing environments is a major concern in oil and gas production. 4130 Cr-Mo alloy steel is widely used as tubing and tubular components in sour services. According to the previous research in aqueous conditions, contact of solid sulfur with alloy steel can initiate catastrophic corrosion problems. This paper discusses elemental sulfur corrosion of Cr-Mo alloy steel in 3.5% sodium chloride solution at pH 2 and 5 during 20 and 30 hours immersion time. The corrosion behavior was monitored by potentiodynamic polarization technique during the experiments. Energy Dispersive X-ray Spectroscopy (EDS), and Scanning Electron Microscopy (SEM) have been applied to characterize the corrosion products after each experiment.