AMPP Store - Online Conference Paper

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Effects of Environmental Exposure on Mechanical and Barrier Properties of an Aircraft Coating System

Product Number: 51324-21200-SG

Author: Attilio Arcari; Steven A. Policastro; Rachel M. Anderson; Carlos M. Hangarter; Erick B. Iezzi

Publication Date: 2024

$40.00

Laboratory and outdoor exposure testing can be used to provide controlled or well-characterized environments for understanding how environmental factors alter coating system properties that can be used to understand systems employed on aircraft. Accurate determination of the state of the coating system would help eliminate unnecessary paint removal operations and thereby reduce worker exposure to, and costs associated with, hazardous materials handling arising from paint removal and repainting operations. A commercial aircraft coating system was exposed to laboratory environmental stressors and outdoor exposure on an atmospheric exposure rack to mimic in-service environments. Equivalent circuit parameter values of electrochemical impedance spectroscopy (EIS) data were linked to mechanisms affecting the deterioration of the coating system in response to in-service environmental exposures. Laboratory and outdoor fatigue testing of the coating system and primer coating resulted in cracking of the coating layers. These cracks allowed faster ingress of electrolyte, as seen in EIS measurements, which would shorten the lifespan of the coatings. Area scans using a scanning Kelvin probe instrument were consistent with the EIS interpretation of fatigue degrading the coating barrier properties, while scanning electron microscopy (SEM) images showed an increased linear density of pretreatment cracks in the fatigued coating samples.

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Effects of Minor Alloying Elements on the Metal-Dusting Behavior of Ni-Based Alloys

Product Number: 51320-14657-SG

Author: Bingtao Li, Wei-Ting Chen, Brian Gleeson, Heike Hattendorf

Publication Date: 2020

$20.00

Alloys are often found to suffer much greater metal-dusting attack under high-pressure conditions compared to ambient-pressure conditions. Ultimately, the resistance of a given alloy to metal dusting depends on the formation of an oxide scale that is impermeable to carbon which, in turn, depends on scale composition and structure. This paper reports the metal-dusting behavior of several Ni-based alloys having relatively high Cr contents (about 30 wt.%) and different controlled minor levels of Fe, Al, and/or Si. Testing was conducted under 20 bar total pressure of a high-carbon-activity gas at 600 °C (1112 °F). The exposed alloys were analyzed by SEM and TEM techniques to evaluate the oxide scales and evidence of carbon ingress. It was found that aluminum is beneficial to improve metal dusting resistance by reacting to form a continuous inner layer of alumina; whereas iron is detrimental to resistance. Mechanistic aspects of the role(s) played by minor elements in affecting metal-dusting resistance are considered.

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Effects of NaCl on Corrosion and Cracking Susceptibility of OCTG C110 Steel in Sour Environments

Product Number: 51323-19010-SG

Author: Lianlian Liu, Raymundo Case

Publication Date: 2023

$20.00

The catastrophic failure of high-strength low-alloy (HSLA) carbon steel C110 pipelines can cause huge economic loss and environmental pollution. Most studies reported that sulfide stress cracking (SSC) is the principal failure type of C110 pipelines in sour environments. The mechanism of SSC can be described as follows: The adsorbed H2S on the steel surface can accelerate the hydrogen uptake by accelerating the hydrogen reduction reaction and catalyzing the hydrogen absorption process. The absorbed hydrogen atoms accumulate in the stress-concentrated region.

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Effects of Renewable Natural Gas and Hydrogen on Microbially Influenced Corrosion and Souring in Underground Gas Storage

Product Number: 51324-21146-SG

Author: Scott Leleika; Taylor Rambo; Tekle Fida

Publication Date: 2024

$40.00

A bench scale laboratory experiment was conducted to assess the microbial corrosion and souring effects renewable natural gas (RNG) and natural gas amended with hydrogen have on underground gas storage systems. Steel coupon-containing vials inoculated with produced fluid from an underground storage well were subject to different headspace conditions to simulate underground gas storage. The vials were filled with geologic natural gas, geologic natural gas amended with hydrogen, RNG, and RNG amended with hydrogen. Each condition was subject to molecular (qPCR, and 16S rRNA analysis), liquid chemistry (sulfate and volatile fatty acid), corrosion, and headspace chemistry (major components and trace sulfur) analysis in duplicate at three time points. The results showed that levels of sulfide production, microbial community composition, and coupon mass loss did not differ greatly between the natural gas and RNG conditions. However, the presence of hydrogen did increase the levels of sulfide in both geologic and RNG conditions. There was also evidence of significant biotransformation of hydrogen into an organic acid (formate). This experiment has shown that microbes native to underground storage wells could have an impact on gas quality and corrosion (via hydrogen sulfide production) if hydrogen is introduced.

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Effects of Silicon Carbide in Corrosion of A36 Gas Shielded Flux Core Welding

Product Number: 51324-21163-SG

Author: Moe A. Rabea; Herbert Wang

Publication Date: 2024

$40.00

Using Gas Shielded Flux Core welding, a butt joint can be analyzed for surface corrosion. The material used with both of these welding processes in this experiment is 1/4-inch A36 Hot Rolled Flat Bar, cut from a single piece, variations of the stock material are minimized. The material is chosen as it is one of the most prevalent material used in many industries that incorporate heavy steel usage. The flat bar measures 3-inch in width, 1/4-inch in thickness, and are cut into 2-inch test pieces. Two pieces form a single test subject, which are welded together. One set of the test pieces are applied with SiC (Silicon Carbide) before the welding process. Both sets are then welded with Gas Shielded Flux Core welding. The final dimension of the test piece is 1/4-inch x 4-inch x 3-inch. The welded pieces are then subjected to corrosion testing in a salt spray chamber and results are observed. The salt spray chamber is controlled at 1 bar pressure with 180L brine reservoir at 5% NaCl concentration. The temperature is held constant at 45 °C with a humidity of 50%. The test pieces will be subjected to this condition for 96 hours. A parallel corrosion test conducted using 1% HCl solution at ambient temperature, 35 °C, 45°C, and 55°C. The samples are initially weighed and placed in the HCl solution for 24 hours. Weight loss from thermal shock from quenching is also conducted. Subjects are heated to a temperature of 250, 300, 350, 400, 450, 500, 550°C and quenched for 15 minutes. The final weight is then taken. Microhardness testing is conducted on the weldments. The conclusion of the test reveals that with the incorporation of SiC powder into the welding process, it resulted in less corrosion (weight loss), less weight loss from thermal shock, and increased microhardness.

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Effects of temperature on hydrogen absorption into steel bars by cathodic charging in solution containing ammonium thiocyanate

Product Number: 51323-18931-SG

Author: Takuya Kamisho, Ryuta Ishii, Masayuki Tsuda

Publication Date: 2023

$20.00

Steel bars used in pre-stressed concrete structures are constantly subjected to tensile stress, and some steel bars have been reported to fracture due to hydrogen embrittlement. It is important to know the hydrogen embrittlement behavior in steel bars to prevent fracture.

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Efficacy Of MIL-DTL-5541 Compliant Non-Chromate Conversion Coating Repair Materials

Product Number: 51322-17625-SG

Author: David G. Enos, Derek Wichhart

Publication Date: 2022

$20.00

Chromate conversion coatings are relied upon to ensure the long-term corrosion performance and surface electrical properties of aluminum alloys, as well as to improve the bond strength and adhesive properties of organic coatings and adhesives. Chromate based chemistries have been all but eliminated in Europe, and it is believed the Environmental Protection Agency (EPA) will stage their elimination in the USA within the next 5 to 10 years. The development of chemistries to replace chromate has been a hot area of research for over 30 years, and now a series of commercial alternatives have become available. These new coatings differ in their chemistry and performance characteristics, as well as their functional limitations, from chromate.

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Efficiency of Cathodic Protection of Stainless Steel in Confined Area - Further Understanding of the Protection Mechanism through Experimental Testing and Modeling

Product Number: 51324-20639-SG

Author: Charles Leballeur; Jean Vittonato; Nicolas Larché; Hervé Marchebois

Publication Date: 2024

$40.00

Cathodic protection (CP) of carbon steel has been extensively studied for structures exposed to the open sea. However, the knowledge and data available for carbon steel cannot be directly applied to stainless steels, especially in the case of confined surfaces that are prone to crevice corrosion. In the context of stainless steels, confined surfaces (such as the contact surfaces of fasteners or valves) are critical zones as crevice corrosion represents the primary failure mode for passive alloys in seawater. With CP, the local potential achieved in confinement areas is highly dependent on various factors, including the actual geometries (crevice gap, length, local pH and Dissolved Oxygen (DO), ohmic drops, etc.). These factors can raise questions about the actual efficiency of CP if the current cannot reach the confined area. Conversely, if sufficient current can reach the confined area, the risk of hydrogen embrittlement (especially for strain-hardened or precipitation hardened alloys) should be taken into consideration. A specific experimental setup has been constructed to characterize the electrochemical behavior of stainless steel in a confined environment and the physicochemical properties of the confined seawater. The results have shown a complete deaeration of the confined seawater under all test conditions, along with an increase of the pH when CP is applied. The tests have also highlighted the significant impact of slight crevice gap variation on the current distribution. Based on the experimental findings, polarization curves representing confined environments have been generated. These curves have been integrated into a finite element model, allowing for the extrapolation of the experimental results to different crevice geometries. After a few centimeters, little to no current should be able to reach the confined surfaces if the crevice gap is inferior to 10µm. However, the risk of corrosion of stainless steels remains limited due to the local CP-induced chemistry at the interface. The CP also mitigates the ohmic drop in the confined area which also tend to reduce the risk of crevice corrosion.

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Elastomer Compatibility with a Pyrolysis-derived Bio-oil

Product Number: 51320-14613-SG

Author: Michael D. Kass , Christopher J. Janke, Samuel A. Lewis, Sr., James R. Keiser, Raynella M. Connatser

Publication Date: 2020

$20.00

The compatibility of fueling infrastructure elastomers in bio-oil and diesel fuel was determined by measuring the volume swell and hardness before and after drying. The bio-oil was produced via fast pyrolysis from a blend of pine feedstocks. The elastomer materials included two fluorocarbons, six acrylonitirile butadiene rubbers (NBRs), fluorosilicone, styrene butadiene rubber, neoprene, polyurethane, neoprene, silicone, ethylene propylene diene monomer (EPDM), hydrogenated acrylonitrile butadiene rubber (HNBR), a blend of NBR and PVC (OZO), and a blend of epichlorohydrin and ethylene oxide (ECO). The majority of the elastomer materials (except for EPDM, SBR and silicone) exhibited higher volume expansion in bio-oil than in diesel. Excessive swelling was noted for the polyurethane, neoprene and three of the NBRs. In general, the higher polarity of these elastomers more closely aligned with the polarities of the bio-oil versus the diesel fuel. Conversely, EPDM, SBR, and silicone are relatively nonpolar and this matches the low polarity of the diesel fuel, which resulted in higher volume expansion in diesel, rather than the bio-oil for these four polymers.

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Electrochemical And Morphological Investigation Of Corrosion Behavior Of Carbon Steel In A Supercritical CO2 Environment With Presence Of H2S.

Product Number: 51322-18005-SG

Author: Yuan Ding, Chin-Hua “Jim” Cheng, Raymundo Case

Publication Date: 2022

$20.00

Supercritical C_O2 storage has been gaining more attention due to its wider application. It is one of the desirable solutions for reducing C_O2 emission, which is an important contributor to the global climate crisis. In other cases, some of the early applications were focused on the oil and gas industry, by using supercritical CO₂ to sequence the mature wells for better production ^[1],[2]. In those environments, C1018 carbon steel was extensively used, due to its good balance of toughness, strength, and ductility as well as its excellent weldability.

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Electrochemical Assessment Of The Influence Of Temperature On The Pitting Corrosion Reistance Of Metallic Materials In Brines

Product Number: 51322-17738-SG

Author: Helmuth Sarmiento Klapper, Sebastian Jesse

Publication Date: 2022

$20.00

Several industrial applications including the chemical industry and oilfield technology involve frequently halide-containing streams at elevated temperatures, that challenge the pitting corrosion resistance of metallic materials. Pitting susceptibility becomes not only a reject criterion for materials selection during the design stages of engineering components used in these applications. It also constitutes a significant limiting factor to the service life of these components once in service. Therefore, the characterization of the pitting corrosion resistance of metallic materials including the influence that operational factors can have on material’s susceptibility is crucial.

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Electrochemical Behavior Of Transmission Pipeline Steels In Supercritical Carbon Dioxide

Product Number: 51322-17592-SG

Author: Zineb Belarbi, Lucas Teeter, Richard E. Chinn, Margaret Ziomek- Moroz, Ömer N. Doğan

Publication Date: 2022

$20.00

High-pressure steel pipeline is a common, cost-effective method for transporting CO₂ from its point of capture to storage sites¹. In pipeline transport systems, CO₂ is mostly transported in its liquid or supercritical phase, depending on the operating pressure^2,3, which requires compression of CO₂ gas to a pressure above 80 bar (Figure 1) and avoid a two-phase flow regime in the steel pipelines. In the USA, the longest CO₂ pipelines, which transport more than 40 MtCO₂ per year from production point to sites in Texas, where the CO₂ is used for enhanced oil recovery (EOR), operate in the “dense phase” mode and at ambient temperature and high pressure.

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Association for Materials Protection and Performance