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Full-Text Articles in Engineering
Periodic Deprivation Of Gaseous Hydrogen Sulfide Affects The Activity Of The Concrete Corrosion Layer In Sewers, Xiaoyan Sun, Guangming Jiang, Philip Bond, Jurg Keller
Periodic Deprivation Of Gaseous Hydrogen Sulfide Affects The Activity Of The Concrete Corrosion Layer In Sewers, Xiaoyan Sun, Guangming Jiang, Philip Bond, Jurg Keller
Faculty of Engineering and Information Sciences - Papers: Part B
Sulfide induced concrete corrosion significantly reduces the service life of the sewer systems. Gaseoushydrogen sulfide (H2S) levels are a key factor affecting the corrosion rate and thesefluctuate due to thediurnalflow pattern of sewers. Currently, there is little known about how suchfluctuations, in particularthe periodic deprivation of H2S, may affect the corrosion activity. This study investigated the impact ofthe deprivation of H2S on the sulfide uptake rate (SUR) of concrete coupons incubated in laboratorycorrosion chambers. After systematic evaluation of the gaseous H2S concentration profiles of two sewersystems, two types of profiles, i.e. short- (1 h) and long- (12 h) term deprivation …
The Rapid Chemically Induced Corrosion Of Concrete Sewers At High H2s Concentration, Xuan Li, Liza O'Moore, Yarong Song, Philp Bond, Zhiguo Yuan, Simeon Wilkie, Lucija Hanzic, Guangming Jiang
The Rapid Chemically Induced Corrosion Of Concrete Sewers At High H2s Concentration, Xuan Li, Liza O'Moore, Yarong Song, Philp Bond, Zhiguo Yuan, Simeon Wilkie, Lucija Hanzic, Guangming Jiang
Faculty of Engineering and Information Sciences - Papers: Part B
Concrete corrosion in sewers is primarily caused by H2S in sewer atmosphere. H2S concentration can vary from several ppm to hundreds of ppm in real sewers. Our understanding of sewer corrosion has increased dramatically in recent years, however, there is limited knowledge of the concrete corrosion at high H2S levels. This study examined the corrosion development in sewers with high H2S concentrations. Fresh concrete coupons, manufactured according to sewer pipe standards, were exposed to corrosive conditions in a pilot-scale gravity sewer system with gaseous H2S at 1100 ± 100 ppm. The corrosion process was continuously monitored by measuring the surface …
Correlation Between Zn-Rich Phase And Corrosion/Oxidation Behavior Of Sn-8zn-3bi Alloy, Xin Zhang, Chong Li, Zhiming Gao, Yongchang Liu, Zongqing Ma, Liming Yu, Hui Jun Li
Correlation Between Zn-Rich Phase And Corrosion/Oxidation Behavior Of Sn-8zn-3bi Alloy, Xin Zhang, Chong Li, Zhiming Gao, Yongchang Liu, Zongqing Ma, Liming Yu, Hui Jun Li
Faculty of Engineering and Information Sciences - Papers: Part A
The microstructure of Sn-8Zn-3Bi alloy was refined by increasing the solidification rate and the correlation between Zn-rich phase and the corrosion/oxidation behavior of the alloy was investigated. The Zn-rich phase transforms from coarse flakes to fine needles dispersed in the β-Sn matrix with the increase of the cooling rate. The transformation of Zn-rich precipitates enhances the anticorrosive ability of Sn-8Zn-3Bi alloy in 3.5 wt.% NaCl solution. On the contrary, Sn-8Zn-3Bi alloy with a fine needle-like Zn-rich phase shows poor oxidation resistance under air atmosphere, due to the fast diffusion of Zn atoms in Sn matrix.
Corrosion Protection Afforded By Praseodymium Conversion Film On Mg Alloy Aznd In Simulated Biological Fluid Studied By Scanning Electrochemical Microscopy, Seyed S. Jamali, Simon E. Moulton, Dennis E. Tallman, Maria Forsyth, Jan Weber, Azadehsadat Mirabedini, Gordon G. Wallace
Corrosion Protection Afforded By Praseodymium Conversion Film On Mg Alloy Aznd In Simulated Biological Fluid Studied By Scanning Electrochemical Microscopy, Seyed S. Jamali, Simon E. Moulton, Dennis E. Tallman, Maria Forsyth, Jan Weber, Azadehsadat Mirabedini, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
Surface passivation of AZNd Mg alloy with Pr(NO3)3 is studied using scanning electrochemical microscopy (SECM) in surface generation/tip collection (SG/TC) and AC modes. Corrosion protection afforded by the Pr treatment and the degradation mechanism in a simulated biological environment was examined on a local scale and compared with non-treated AZNd. SG/TC mode results revealed a drastic decrease in H2 evolution due to the Pr treatment. Mapping the local insulating characteristics using AC-SECM showed higher conductivity of the surface where H2 evolution was most favorable.
Applications Of Scanning Electrochemical Microscopy (Secm) For Local Characterization Of Az31 Surface During Corrosion In A Buffered Media, Sina S. Jamali, Simon E. Moulton, Dennis E. Tallman, Maria Forsyth, Jan Weber, Gordon G. Wallace
Applications Of Scanning Electrochemical Microscopy (Secm) For Local Characterization Of Az31 Surface During Corrosion In A Buffered Media, Sina S. Jamali, Simon E. Moulton, Dennis E. Tallman, Maria Forsyth, Jan Weber, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
Different modes of scanning electrochemical mapping (SECM) such as surface generation/tip collection (SG/TC), amperometry, AC-SECM and potentiometry were employed to characterize the active/passive domains, hydrogen gas (H2) evolution and local pH on a corroding surface of AZ31 in simulated biological fluid (SBF). It was found that the main domains of H2 evolution are associated with lower insulating properties of the surface as well as higher local pH. The near surface pH was found to be highly alkaline indicating that, even in a buffered solution such as SBF, the local pH on a corroding AZ31 surface can be significantly different to …
Thermodynamic Considerations Of The Corrosion Of Nickel Ferrite Refractory By Na3alf6-Alf3-Caf2-Al 2o3 Bath, Raymond Longbottom, Sharon Nightingale, Brian Monaghan
Thermodynamic Considerations Of The Corrosion Of Nickel Ferrite Refractory By Na3alf6-Alf3-Caf2-Al 2o3 Bath, Raymond Longbottom, Sharon Nightingale, Brian Monaghan
Faculty of Engineering and Information Sciences - Papers: Part A
Thermodynamic analysis was carried out to interpret the results of corrosion testing of nickel ferrite samples in cryolite-based baths. The equilibrium between cryolite-based baths and nickel ferrite was considered. Isopleths between cryolite-based baths and nickel ferrite confirmed that for the temperature range of interest (1223-1273 K) there was limited solubility of nickel ferrite in the bath. To better understand the formation of the metal from nickel ferrite, the effect of reducing potentials on nickel ferrite and nickel ferrite-cryolite-based bath systems were considered. The formation of a metal phase was predicted at relatively high pO2. The metal phase was nickel-rich at …
Influence Of Fluoride And Chromium(Vi) Ions On Corrosion Mechanisms Of Pb-3wt%Sn-0.5wt%Ag Anode, Jianzhong Li, Xiuli Sun, Yanwen Tian, Yue Zhao
Influence Of Fluoride And Chromium(Vi) Ions On Corrosion Mechanisms Of Pb-3wt%Sn-0.5wt%Ag Anode, Jianzhong Li, Xiuli Sun, Yanwen Tian, Yue Zhao
Faculty of Engineering and Information Sciences - Papers: Part A
A mix solution of fluorine and chromium ions (Cr-F solution) for applications in chromium plating field has a characteristic of strong corrosion and oxidation, promoting lead alloys anode degraded rapidly. The present study explores the time dependence on corrosion mechanisms of lead alloys anode oxidised in Cr-F solution under conditions of high current density. Scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX) shows a double-layer oxide film is electrochemically developed on lead alloys anode after oxidation for above 0.5h. The outer layer is primarily PbO and PbO2, and the inner layer contains PbCrO4 and PbF2, followed by …
Laboratory Study On Rockbolt Corrosion, Naj Aziz, P Craig, Jan Nemcik
Laboratory Study On Rockbolt Corrosion, Naj Aziz, P Craig, Jan Nemcik
Faculty of Engineering and Information Sciences - Papers: Part A
The effect of long term exposure of full size bolts to corrosive environments is presented. A special test rig was used to test four bolts under different loading conditions. Four, X-grade identical corrosioin testing using acid sulphate water. the pH value of the curculated water varied between 3.4 and 4.3. The corrosion exposure test period lasted three and half years. Two bolts were axially loaded to 10 and 20 tonnes force respectively, the third bolt was subjected to a 360 Nm torsion load and the fourth bolt was left unstressed to act as a reference bolt. After the test period …
In Vitro Studying Corrosion Behaviour Of Biocorrodible Mg Alloys, Sina S. Jamali, Simon Moulton, Maria Forsyth, Gordon G. Wallace
In Vitro Studying Corrosion Behaviour Of Biocorrodible Mg Alloys, Sina S. Jamali, Simon Moulton, Maria Forsyth, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
The idea of bioabsorbable/biocorrodible stents has gained increasing attention in the last decade. Permanent coronary stents, traditionally made from 316L grade stainless steel, are routinely used for the treatment of blocked arteries. However, these stents can cause complications such as restenosis, thrombosis and the need for the patient to undergo prolonged antiplatelet therapy. Biodegradable metal stents provide an opportunity for the stent to remain in place for a period to ensure restoration of function and then degrade through a carefully controlled bio-corrosion process. Among the number of potentially suitable materials, Magnesium alloys have shown great promise as a stent material …
The Effects Of An Applied Voltage On The Corrosion Characteristics Of Dense Mgo, Brian Joseph Monaghan, Sharon Nightingale, Qiang Dong, Michael Funcik
The Effects Of An Applied Voltage On The Corrosion Characteristics Of Dense Mgo, Brian Joseph Monaghan, Sharon Nightingale, Qiang Dong, Michael Funcik
Faculty of Engineering - Papers (Archive)
In a recent investigation Mills and Riaz [1] showed that industrial oxide refractory corrosion by liquid oxides could be changed by the application of a small voltage across the liquid oxide-refractory interface. They ex-plained their result in terms of penetration of the refractory pores with liquid oxide. Their analysis of the corrosion effect was to some degree limited by the use of an industrial refractory material in the study. Fur-ther, it was not clear whether their findings were limited to solely industrial refractories or had wider ranging application to more dense ceramic type solid oxide systems. In this study, a …
Refractory Corrosion By Slag Under An Applied Voltage, Brian J. Monaghan, Sharon Nightingale, Q Dong, Michael Funcik
Refractory Corrosion By Slag Under An Applied Voltage, Brian J. Monaghan, Sharon Nightingale, Q Dong, Michael Funcik
Faculty of Engineering - Papers (Archive)
The effect of an applied voltage on the dissolution rate of MgO refractory in two steelmaking type slags has been investigated. It was found that the MgO corrosion in a CaO-SiO2-Al2O3 based slag proved insensitive to an applied voltage over the voltage range –0.5 to 0.3V. The corrosion rate of the dense MgO in a CaO-SiO2-Fe2O3-FeO-MgO slag showed a maximum corrosion rate at –0.45V. This effect has been explained by considering the consequences of an applied voltage on the rate of Marangoni flow at the slag-refractory-gas interface and in turn, the flow effect on the rate of the mass transfer …
The Effect Of An Applied Electrical Potential On Refractory Corrosion By Slag, Brian J. Monaghan, Sharon Nightingale, Q Dong
The Effect Of An Applied Electrical Potential On Refractory Corrosion By Slag, Brian J. Monaghan, Sharon Nightingale, Q Dong
Faculty of Engineering - Papers (Archive)
An investigation has been carried out to assess the effects of an applied voltage on the dissolution rate of MgO refractory in a steelmaking like slag. In this study corrosion results obtained from dip tests using a dense direct bonded MgO refractory in a CaO-SiO2-Fe2O3-FeO-MgO slag are presented. These results demonstrate that the application of a voltage across a dense MgO refractory-slag interface can change the rate of refractory dissolution. For the slag composition used and the voltage range tested, it was found that a maximum corrosion rate was obtained at a voltage setting of –0.45V. The results of this …