Epoxy Sealant Research Articles

Effect of Epoxy Sealant Loaded with Modified Montmorillonite on the Corrosion Resistance of Fe-Based Amorphous Metallic Coating

Effect of Epoxy Sealant Loaded with Modified Montmorillonite on the Corrosion Resistance of Fe-Based Amorphous Metallic Coating

Experimental investigation on immersion liquid cooled battery thermal management system with phase change epoxy sealant

To improve the working performance of the lithium-ion batteryin continuous operation under waterconditions, a novel immersion liquid cooled battery thermal management system (BTMS) with epoxy sealant based composite phase change (ESPE) is designed forlithium-ion batteries. Considering the traditional liquid cooling systems with complex auxiliary equipment, the battery module with ESPE exhibits an excellent cooling effectiveness and displays long-term corrosion resistance performance. The thermal performances of epoxy sealantwith or without the addition of paraffin, expanded graphite are compared, respectively. The experimental results indicate that ESPE exhibits excellent waterproof and thermal management performance. Even during 3C charge and discharge cycle, the maximum temperature and the maximum temperature difference can be maintained at 42 °C and 2 °C, respectively. With these prominent performances, the designed BTMS with respect to excellent waterproof and prominent thermal management performances can significantly reduce the unnecessary power consumption of liquid cooling and provide insights into the passive BTMS.

The chemistry insight: epoxy sealant as an alternative remedial operation for well integrity

Abstract Epoxy resin is commonly used in the oil and gas industry due to its excellent toughness, low shrinkage, good adhesive strength, and relatively good thermal resistance. It is used for water shutoff, zonal isolation, cementing, enhanced oil recovery, and preventing leakage in wells. This paper reviews the chemistry aspect of using an epoxy resin system as a sealant to prevent well leakage and it offers insights into the chemistry of the epoxy resin system, as applied in previous studies. The paper also unveils the reasons for the application of this system from the chemistry perspective, allowing this aspect to be better understood. Success in the investigated cases depended on the formulation design. The epoxide and hydroxyl functional groups have been found to contribute substantially to the excellent performance of the sealant system. Furthermore, the amine curing agent triggers the abrupt reaction of the oxirane ring to stabilise when the cured sealant is perfectly applied. Based on the findings, it is suggested that other types of epoxies, namely epoxidised oils, require further study. Finally, in terms of safety and sustainable energy, it is suggested that more curing agent and diluent studies are undertaken.

Effect of sodium hypochlorite, isopropyl alcohol and chlorhexidine on the epoxy sealant penetration into the dentinal tubules.

The sealer penetration into the dentinal tubules might be beneficial, especially in necrotic endodontic cases, as it provides the obstruction of the contaminated tubules. To determine the effect of 3 final irrigants (sodium hypochlorite (NaOCl), alcohol and chlorhexidine (CHX)) on the penetration of an epoxy sealer into the dentinal tubules. The study was carried out on 60 single-canal human teeth with straight roots. The root canals were prepared to the ISO 40/04 size, using the Reciproc® instruments. The teeth were divided into 4 groups (n = 15). The canals in each group were irrigated according to the following scheme: group 1 (control) - 5.25% NaOCl; group 2 - smear layer removal (40% citric acid (CA) and 5.25% NaOCl) and 5.25% NaOCl; group 3 - smear layer removal (as in group 2), and 40% CA, water and 98% isopropyl alcohol; and group 4 - smear layer removal (as in group 2), and 40% CA, water and 2% CHX. The root canals were filled using the vertical condensation technique with gutta-percha and the porphyrin-labeled AH Plus™ sealer. After 3 days, 1-milimeter-thick cross-section slices were cut from the roots at a distance of 2 mm, 5 mm and 8 mm from the apex. The sections were imaged under a confocal microscope and the sealant penetration depth into the dentinal tubules was measured. The longest resin tags in all parts of the roots were found in group 4 (CHX), and the shortest in group 1 (control). The mean depth of the sealer penetration (in micrometers) was as follows: 21, 22 and 23 (group 1); 201, 231 and 374 (group 2); 170, 232 and 280 (group 3); and 330, 408 and 638 (group 4) in the apical, middle and coronal parts, respectively. The final irrigation with CHX resulted in the deepest penetration of the epoxy sealer into the tubules. Isopropyl alcohol had the most negative impact on the sealer penetration into the tubules.

Experimental Investigation on Immersion Liquid Cooled Battery Thermal Management System with Phase Change Epoxy Sealant

Experimental Investigation on Immersion Liquid Cooled Battery Thermal Management System with Phase Change Epoxy Sealant

Evaluation of adhesion of epoxy resin sealant to improve the corrosion resistance of thermal sprayed coatings

The adhesion of coatings on a given substrate has fundamental importance on a coating/substrate system's functionality. The current paper presents the adhesion strength results of FeCr and CoCr-based deposits produced by the electric arc thermal spray process on carbon steel, with an intermediate layer of 95Ni5Al. Three chemical compositions were tested for coating deposition and were characterized using plate and tube specimens made of carbon steel UNS G10200 to result in a screening of performance. Microstructural evaluation by optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were performed. Coating strength was measured using the standard pull-off test method. The corrosion resistance was analyzed with salt spray exposure, electrochemical polarization, and impedance spectroscopy (EIS) tests. The adhesion strength of FeCr and CoCr alloy coatings shows an overall average tensile strength of 27.2 MPa. All sealed conditions presented low corrosion and the samples with epoxy sealant exhibited a high resistance against corrosion. The X-ray diffraction results have revealed alpha and gamma FeCr alloys and chromite as deposited phases after the coating process.

Comparative study on tribological and corrosion protection properties of plasma sprayed Cr2O3-YSZ-SiC ceramic coatings

In this research, the tribological and corrosion protection properties of atmospheric plasma sprayed Cr2O3-20YSZ (CZ) and Cr2O3-20YSZ-10SiC (CZS) composite coatings on 304 L stainless steel substrates were evaluated and compared to pure Cr2O3 (C) coating. Microstructural evaluations were carried out using an optical microscopy, X-ray diffraction (XRD) analysis, and a Field Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS). The ball-on-disk wear test was performed using an alumina counterpart at room temperature. The protective efficiency of the coatings with/without sealing treatment was evaluated by electrochemical potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5 wt% NaCl solution. Evaluation of wear tracks showed that enhancement of the wear resistance of the composite coatings was ascribed to the zirconia phase transformation toughening and the presence of more ductile tribofilms participated in pore filling during the wear. The corrosion measurements revealed that the protection properties of the coatings were strongly dependent on the porosity content so that the as-sprayed coatings due to their porous nature could not protect the substrate. However, filling the porosity using an epoxy sealant prevented the penetration of the corrosive environment into the substrate and therefore increased the protective efficiency of the coatings. Moreover, the density of the unfilled defects such as micro-cracks determines the protection properties of the sealed coatings, so that the CZ coating due to its highest toughness had the lowest micro-crack density and thus the highest protective efficiency.

Technology Update: New Tool and Sealant Technology Expedites Annular Isolation Tasks

Technology Update Annular isolation issues are frequently discussed in well asset forums worldwide with a focus on improved oil recovery/ enhanced oil recovery applications or annular well integrity challenges. Conventional methods to repair annular isolation typically involve coiled tubing (CT) operations or heavy workovers, where it is necessary to pull the well tubing. These are high-cost procedures that are sometimes deferred. We discuss herein the CannSeal technology, a well intervention tool that conveys and accurately places a proprietary epoxy sealant into an annulus at a predefined location in the well. The technology enables a level of precision in the placement of annular sealant that has not previously been possible. Considerable savings in rig time can be achieved, compared with alternative methods. Operators can use the technology to isolate and improve the response to reservoir issues such as high water cuts and thief zones and efficiently repair and re-establish well barriers. As a result, well recompletions can be postponed or avoided. The results of a field trial are included in this discussion. The Technology The technology was patented in 2005, following a joint industry project between Shell, Statoil, Eni, Total, and the Research Council of Norway. A field trial was performed in 2012 with Shell Appalachian in Pennsylvania (United States) with partial success, but revealed the need for further design improvements. ConocoPhillips, Maersk Oil, and BP contributed financially to support considerable reengineering and rigorous testing. Eventually, Maersk and BP spent resources on the final tool qualification processes to ensure that the equipment was ready for downhole operations. In late 2015, the tool was successfully run at Maersk’s Halfdan field in Denmark. The technology concept consists of an electrical-wireline- or electrical-CT- (e-CT-) operated tool that incorporates the epoxy sealant. The sealant is premixed in the workshop and transferred to a steel container/canister within the tool assembly. The tool incorporates an advanced telemetry communication system that provides the tool operator at the surface full control of Position, using the integrated casing collar locator (CCL) All tool functions Perforation Pumped sealant volume Sealant injection rate and pressure Tool and well pressures and temperatures Emergency release features When located at the precise target depth in the well, a three-hole perforation process is activated, which allows access to the entire circumference of the annulus. The sealant is injected and displaced exclusively into the annulus in a single operation without sealant spilling into the tubing (Fig. 1). The sealant will also seal the perforated holes without the subsequent need for patching. If the sealant is injected into a cement matrix for microannulus repair, a pumping differential pressure of 200 bar is achievable. The proprietary sealant is designed with rheology properties that allow it to be injected into an open/cased-hole annulus with possible crossflow of water or into a gravel pack or cement matrix. The epoxy plug solidifies under well temperature conditions.

Assessment of bioburden encapsulated in bulk materials

The National Aeronautics and Space Administration (NASA) imposes bioburden limitations on all spacecraft destined for solar system bodies that might harbor evidence of extant or extinct life. The subset of microorganisms trapped within solid materials during manufacture and assembly is referred to as encapsulated bioburden. In the absence of spacecraft-specific data, NASA relies on specification values to estimate total spacecraft encapsulated bioburden, typically 30endospores/cm3 or 300 viable cells/cm3 in non-electronic materials. Specification values for endospores have been established conservatively, and represent no less than an order of magnitude greater abundance than that derived from empirical assessments of actual spacecraft materials. The goal of this study was to generate data germane to determining whether revised bulk encapsulated material values (lower than those estimated by historical specifications) tailored specifically to the materials designated in modern-day spacecraft design could be used, on a case-by-case basis, to comply with planetary protection requirements.Organic materials having distinctly different chemical properties and configurations were selected. This required more than one experimental and analytical approach. Filtration was employed for liquid electrolytes, lubricants were suspended in an aqueous solution and solids (wire and epoxy sealant) were cryogenically milled. The final data characteristic for all bioburden estimates was microbial colony formation in rich agar growth medium. To assess survival potential, three non-spore-forming bacterial cell lines were systematically encapsulated in an epoxy matrix, liberated via cryogenic grinding, and cultured. Results suggest that bulk solid materials harbor significantly fewer encapsulated microorganisms than are estimated by specification values. Lithium-ion battery electrolyte reagents housed fewer than 1CFU/cm3. Results also demonstrated that non-spore-forming microorganisms are capable of surviving encapsulation within, and liberation from, epoxy solids. It must be noted, however, that all purposely spiked experimental solids, resulted in very low recovery (1×10−3–1×10−5CFU/cm3) of viable organisms.

High frequency guided ultrasonic waves for hidden fatigue crack growth monitoring in multi-layer model aerospace structures

Especially for ageing aircraft the development of fatigue cracks at fastener holes due to stress concentration and varying loading conditions constitutes a significant maintenance problem. High frequency guided waves offer a potential compromise between the capabilities of local bulk ultrasonic measurements with proven defect detection sensitivity and the large area coverage of lower frequency guided ultrasonic waves. High frequency guided waves have energy distributed through all layers of the specimen thickness, allowing in principle hidden (2nd layer) fatigue damage monitoring. For the integration into structural health monitoring systems the sensitivity for the detection of hidden fatigue damage in inaccessible locations of the multi-layered components from a stand-off distance has to be ascertained. The multi-layered model structure investigated consists of two aluminium plate-strips with an epoxy sealant layer. During cyclic loading fatigue crack growth at a fastener hole was monitored. Specific guided wave modes (combination of fundamental A0 and S0 Lamb modes) were selectively excited above the cut-off frequencies of higher modes using a standard ultrasonic wedge transducer. Non-contact laser measurements close to the defect were performed to qualify the influence of a fatigue crack in one aluminium layer on the guided wave scattering. Fatigue crack growth monitoring using laser interferometry showed good sensitivity and repeatability for the reliable detection of small, quarter-elliptical cracks. Standard ultrasonic pulse-echo equipment was employed to monitor hidden fatigue damage from a stand-off distance without access to the damaged specimen layer. Sufficient sensitivity for the detection of fatigue cracks located in the inaccessible aluminium layer was verified, allowing in principle practical in situ ultrasonic monitoring of fatigue crack growth.

Ventilation Fan Fires: Overheated Windings Lead to Failed Thermal Limit Switch

Over the last several years, the forensic community has experienced an increase in the number of fires which have been attributed to ventilation fans. These failures have been anecdotally observed in Jakel motors, specifically model numbers J239-050-5138 and J238-050-5494, manufactured between 2000 and 2003. While there have been a number of variations to motors within exhaust fans over the preceding decades, including different winding size, winding metal, and thermal cut-off (TCO) manufacturers, two design implementations have led to the higher incidents of failure. The first design change is the implementation of 27 American Wire Gauge aluminum winding (magnet) wire. The second, and most important, is the implementation of the Tamura Thermal Device Corporation (TAM) TCO to replace the Elmwood Sensor/Honeywell (Elsen) TCO. Through investigations and testing, the Tamura TCO has been found to be unreliable at opening the circuit within the motor when exposed to temperatures above its specified cut-off temperature (136°C). Thermal testing of a Tamura TCO showed that even when exposed to temperatures as high as 260°C, the flux of the fusible thermal link is incapable of breaking down the oxides created by the metal alloy. The hypothesized failure mechanism for the Tamura TCO include increased exposure to high temperatures during fan operation and/or air infiltration from cracks in the epoxy sealant due to improper installation, along with the corrosive effects of the chlorinated flux. This work presents case studies, experimentation, and analysis of the failure mechanisms related to fires associated with the aforementioned motors.

Thermal resistance of CNTs-based thermal interface material for high power solid state device packages

Vertically aligned carbon nanotubes (VACNTs) were synthesized over copper substrate. The diameter and length of the CNTs were 100 nm and 2–3 μm, respectively. Synthesis of CNTs was confirmed by Raman spectrum and verified by TEM as multi walled CNTs. SEM images showed the vertically aligned CNTs over Cu substrate. Strengthening of CNTs was performed by filling with Cu and SU-8 epoxy sealant in gap between the CNTs. The observed density was high for epoxy sealed CNTs. The bending ability of CNTs was checked and observed as low for epoxy sealed CNTs. The thermal resistance of the samples was measured by JESD51-2 standard for various loads. The observed resistance was low (0.277 cm2 K/W) for epoxy sealed CNTs at 1100 kPa. The calculated resistance of CNTs alone was 0.097 cm2 K/W for epoxy sealed at 900 kPa.

Application of liquid desiccant for enhanced lifetime of active matrix organic light emitting diodes

ABSTRACTTo enhance the lifetime of large-sized active matrix organic light emitting diodes (AMOLEDs), we developed a liquid desiccant for encapsulation. The liquid desiccant was prepared by mixing nano-sized calcium oxide (CaO) powders and silicone binder including polyalkylalkenylsiloxane, polyalkylhydrogensiloxane and platinum compound. It was confirmed that liquid desiccant had an effect on absorption of penetrated moisture and oxygen through calcium tests. Also, the test cells encapsulated with only epoxy sealant dispensed at the edge of the cell developed dark spots within 100 hrs, which grew larger with time at 85 oC and 85 % R.H. On the other hand, the test cell sealed with epoxy sealant and liquid desiccant showed no dark spots and retained 97% of its initial luminance even after being stored for 800 hrs at 85 oC and 85 % R.H. Furthermore, the accelerating storage lifetimes of 31-inch bottom-emitting AMOLEDs with epoxy sealant and liquid desiccant showed about 1000 hrs. These results suggest that the liquid desiccant can be applied to encapsulation of large-sized AMOLEDs.

A technique to produce aluminum color bands for avian research

We developed a technique to produce metal (aluminum) color bands, in response to concerns about leg injuries caused by celluloid-plastic color bands applied to Willow Flycatchers (Empidonax traillii). The technique involves color-anodized aluminum bands (unnumbered blanks and federal numbered bands), with auto pin-striping tape and flexible epoxy sealant, to create a variety of solid, half- and triple-split colors. This allows for hundreds of unique, high-contrast color combinations. During six consecutive years of application, these colored metal bands have resisted color fade compared to conventional celluloid-plastic bands, and have reduced leg injuries in the flycatcher. Although not necessarily warranted for all color-banding studies, these metal bands may provide a lower-impact option for studies of species known to be impacted by plastic color bands.

CVD of Alumina on Carbon and Silicon Carbide Microfiber Substrates for Microelectrode Development

Using a vacuum CVD technique, alumina films were deposited on 10 μm diameter carbon fibers, and 120 μm diameter silicon carbide fibers. This was accomplished by exposing resistively heated microfiber substrates to a sublimate of [Al(O- t Bu) 3 ] 2 , while the reaction chamber was maintained at 120 °C under a pressure of 0.15 torr. The coated substrates were then sealed into glass capillaries, using an epoxy sealant, to form microelectrode devices. The quality of the alumina films was found to be dependent on the substrate temperature, with optimum film quality being obtained at substrate temperatures between 750 °C and 800 °C. Film thickness was controlled by deposition time, and films from 1-100 μm were routinely produced. Films were characterized by microscopy and electrochemical techniques.

Chemical Vapor Deposition Fabrication and Characterization of Silica-Coated Carbon Fiber Ultramicroelectrodes

Carbon fiber disk ultramicroelectrodes (UMEs) with well-defined geometries were prepared by chemical vapor deposition techniques. Transparent silica films with thicknesses from 1 to 600 microns were deposited on the cylindrical length of 5 and 10 microns carbon fibers from a SiCl4, H2, and O2 ternary precursor system at 850-1150 degrees C or sequential deposition from Si(OEt)4 as a single source precursor at 700 degrees C followed by the SiCl4, H2, and O2 precursor system. Film thickness, film adhesion to the fiber substrate, and the overall dimensions of the silica-coated carbon fiber were studied and found to be a function of the precursor system, precursor concentrations, fiber diameter, deposition time, and fiber temperature. The silica films were found to be free of microcracks and characterized by a quality seal between the carbon fiber and the coating. As a result, the silica-coated disk UME exhibits an excellent electrochemical response without the need to use an epoxy sealant at the electrode tip. Furthermore, the deposition of hard and inert ceramic materials imparts durability to fragile carbon fibers and facilitates the handling of UMEs in microenvironments. Finally, the advantage of concentric deposition about the fibers to produce a disk UME in the center of an insulating plane was used to examine the effect of the thickness of the insulating coating on the limiting current response.

Erythema multiforme after contact dermatitis in response to an epoxy sealant

A case of erythema multiforme associated with an allergic contact dermatitis in response to an epoxy-based compound is presented. Patch tests revealed a positive reaction to both the epoxy resin and the hardener. Chemicals applied directly to the skin should be considered as a potential cause of erythema multiforme.

Electrochemical corrosion studies of alloys plasma sprayed with Cr 2O 3

Summary Interconnected porosity in a thermal spray coating may act as a crevice which may allow crevice corrosion of some substrates. A potentiodynamic cyclic polarization technique was used to evaluate the corrosion resistance of 316L stainless steel and Inconel 625 (IN-625) coated with Cr 2 O 3 by plasma spraying. The corrosion resistance of coated samples was found to be dominated by the characteristics of substrate alloys; coated 316L exhibited crevice corrosion while coated IN-625 exhibited no corrosion. The effectiveness of an epoxy sealant was also determined. The epoxy sealant used in this study was found to be very effective in enhancing the corrosion resistance of the thermally sprayed coated sample. Post-analyses of the corroded samples were carried out using optical and scanning electron microscopy. The results were compared with salt spray testing.

An easy sealing MAS rotor insert for liquids, gels, and air-sensitive solid samples

Recent attempts to seal MAS rotors for obtaining CP/MAS spectra of air-sensitive materials and/or liquids and gels have involved either heat sealing glass inserts (1, 2) or machining Kel-F inserts that require heat fusing a machined cap to the rotor top (3). Heat sealing of glass inserts presents problems when volatile solvents are used due to the proximity of the heat source to the sample (3). While easily machinable, the Kel-F inserts are not easily formed and sealing using a hot rod on the insert cap may not be complete. We report the design and use of a glass MAS rotor insert that uses an epoxy sealant, not heat sealing, and can be obtained commercially to fit a variety of rotor designs. Figure 1 shows that the Pyrex MAS rotor insert (Part No. SK-2 133, Wilmad Glass Co.) for the double-bearing Kel-F (Chemagnetics Inc.) rotors used in a M-100s 13C

Freezing Pipe-Type Cable Oil with Liquid Nitrogen

Utilizing a concentric aluminum shell, aluminum foil, an epoxy sealant, and liquid nitrogen, an efficient and simple freeze chamber was designed and fabricated which is capable of effectively freezing pipe-type cable oil in a relatively short time. Designed to contain liquid nitrogen in contact with the pipe surface, the chamber permits heat absorption at a maximum rate. The short freeze times and freeze lengths attained by utilizing the cold temperature characteristic of liquid nitrogen indicate this technique to be a highly satisfactory method of sectionalizing oil in high-voltage pipe-type circuits in minimum time.