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Does temperature have an effect in coating thickness reading ? / David J. Barnes in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 9 (09-10/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 9 (09-10/2018) . - p. 14-16 Titre : Does temperature have an effect in coating thickness reading ? Type de document : texte imprimé Auteurs : David J. Barnes, Auteur Année de publication : 2018 Article en page(s) : p. 14-16 Langues : Américain (ame) Catégories : Epaisseur -- Mesure Essais (technologie) Revêtements Température Ultrasons Index. décimale : 667.9 Revêtements et enduits Résumé : A simple search of the internet will tell you that the speed of sound in a material changes with temperature. Concern has therefore been expressed that temperature may have a noticeable effect on the speed of sound when taking coating thickness measurements with an ultrasonic gauge. The method of measuring the coating thickness using ultrasonics is defined in ASTM D6132-13 as follows. Instruments complying with this test method measure thickness by emitting an ultrasonic pulse into the coating that is reflected back from the substrate to the probe. The travel time is converted into a thickness reading. The instrument's probe must be placed directly on the coating surface to take a reading. After verifying accuracy on a known coated part of the object or material of the same kind, the instrument probe is coupled with the coated specimen, after proper cure and conditioning according to the coating manufacturer's instructions. It should be recognized that the accuracy of the measurements can be influenced when : The coated object to be measured is not planar with respect to the transducer face at the point of measurement, Coating density is not uniform, and The substrate peak-to-valley surface profile of the coated specimen exceeds the coating thickness. While the theory of ultrasonic measurement can be a daunting proposition to some users, gauges produced today are essentially "point-and-shoot" devices - the user simply reads the thickness, in digits off of the gauge screen; there is no opportunity for confusion or for different operators to read the numbers differently. However, the onus is on the operator to verify that the gauge is reading correctly, and if temperature might affect this, the operator needs to take note and adjust accordingly. This article looks at the effect of temperature on the speed of sound in coating materials and the subsequent effect on coating thickness readings. Note de contenu : - Table 1 and 2 : Sample Thickness Reading with Gauge A Calibrated at Each TEst Temperature. - Table 3 : Sample Measured at Each Norminal Test Temperature with Gauge A Calibrated at Room Temperature Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31889 [article]

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Extending fish hold tank maintenance intervals on the F/V Cornelia Marie / Ray Meador in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 9 (09-10/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 9 (09-10/2018) . - p. 18-22 Titre : Extending fish hold tank maintenance intervals on the F/V Cornelia Marie Type de document : texte imprimé Auteurs : Ray Meador, Auteur Année de publication : 2018 Article en page(s) : p. 18-22 Langues : Américain (ame) Catégories : Bateaux -- Entretien et réparations Bateaux -- Revêtements:Bateaux -- Peinture Epoxydes Haut extrait sec Polyamines Revêtements protecteurs Index. décimale : 667.9 Revêtements et enduits Résumé : In the commercial fishing industry, as with any other industry in which corrosion can affect the bottom line. And when a vessel shows up at a processing plant with fish hold tanks containing rusty water or floating paint chips, the processor may refuse the contaminated load, causing the owner to lose out on an entire haul. Proactively addressing fish hold maintenance can be tough for vessel owners, as the thin-film polyamide epoxy coatings traditionally used to coat fish holds need to cure for about a week before returning the tanks to service. That's a lot of downtime to plan for in dry-dock when other areas of the vessel are likely prioritized for coatings maintenance. Making matters worse, the polyamide epoxy coatings typically last only about five years, forcing vessel owners to keep up with short maintenance intervals. McManus prefers to take his risks crabbing in the unforgiving Bering Sea — not at a sea-food processing facility where a contaminated load of king crab could mean a loss of more than $560,000 per fish hold at dock prices. To protect potential catch, he recently restored six fish holds of his boat. In doing so, he also made a strategic specification change based on the recommendation from a global coating manufacturer's technical representative to switch from a traditional polyamide epoxy coating to a more durable ultra-high-solids epoxy amine coating that could deliver a longer service life and triple the expected fish hold maintenance interval to about 15 years. "The beauty in the fish hold coating application was in prepping the tanks efficiently, coating them within a couple of days, and returning them to service 24 hours later, knowing that we may not have to redo them for another 15 years". Note de contenu : - Fish hold restoration - Hull, freeboard and superstructure reconditioning - Fig. 1 and 2 : The Cornelia Marie's six fish holds showed visible signs of corrosion - Fig. 3 : Abrasive blast-cleaning the fish holds to an SSPC SP-10 standard removed all coatings and contaminants from th esteel substrates - Fig. 4 and 5 : An epoxy coating was applied at a 20-to-30-mils DFT over all the fish hold surfaces, including sharp edges, corners and grates - Fig. 6 : The Cornelia Marie crew applied three coats of epoxy to the vessel's main deck by brush and roller - Fig. 7 : Work on the underwater hull and freeboard of the Cornelia Marie involved taking the surface down to an existing tight antifouling coat, priming exposed bare steel, edge feathering above the waterline and spray-applying primer, an antifouling epoxy and an acrylic polyurethane gloss coating Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31892 [article]

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No magic number / R. A. Nixon in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 9 (09-10/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 9 (09-10/2018) . - p. 24-31 Titre : No magic number : coating concrete after 28 days Type de document : texte imprimé Auteurs : R. A. Nixon, Auteur Année de publication : 2018 Article en page(s) : p. 24-31 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Matériaux cimentaires -- Revêtements:Matériaux cimentaires -- Peinture Matériaux cimentaires -- Séchage Rétrécissement (matériaux) Index. décimale : 667.9 Revêtements et enduits Résumé : Historically, the coating industry has prescribed 28 days of cure time for concrete before coating application. The 28-day threshold was based on conventionally specified strength gain values such as a minimum of 5,000 psi compressive strength at 28 days. The logic behind the adoption of the 28-day rule was twofold. Firstly, the majority of minimum specified strength gain is empirically reached within the first 28 days. Therefore, if the compressive strength has mostly been achieved, then most of the tensile stress that forms cracks will have developed. This assumes that most of the shrinkage of the cement paste has largely occurred but ignores the all-important water-to-cementitious-materials ratio and the paste-to-aggregate ratio. These are the major contributors to shrinkage along with temperature and timing of excess moisture loss from the concrete. Coincidently, these factors are both inextricably tied to the water content in the mix design, which leads us to point number two. Typically, it is believed that all of the excess water not necessary for cement hydration has left the concrete after 28 days. Therefore, the detrimental effects from the exit of moisture from the concrete on coating cure or coating adhesion have been eliminated. This assumes that excess moisture leaving the concrete after 28 days will not inhibit a coating's curing mechanisms. This also ignores the material principles at work in cement hydration. The problem with the magic 28-day number is that there is just as much empirical evidence that 28 days isn't necessary, as there is for its requirement or a longer cure time prior to coating. This article will discuss the many factors affecting the timing for concrete shrinkage (and related cracking) as well as the rate of loss of excess moisture - factors that are not reliant on 28 days of concrete cure time. In addition, case histories will be presented evidencing sucessful coating application on concrete well before 28 days of cure time versus coating problems experienced well beyong 28 days of concrete cure. Further, we will examine mix design and material-related parameters that should be followed when scheldule needs for coating concrete prior to 28 days of cure are essential. Note de contenu : - The basics - Drying shrinkage and excess water in concrete substrates - Real-world experience - Fig. 1 : Concrete shrinkage increases with the water-to-cement for a given aggregate content - Fig. 2 : This graph shows the typical effect of water content on drying shrinkage - Fig. 3 : Reflective cracking which appeared approximately one month after a floor coating system was installed in a pharmaceutical plant - Fig. 4 : No reflective cracking and no moisture-related problems have been observed since this floor coating was installed in a building at a wastewater treatment plant after two years in service - Fig. 5 : Blisters formed in the coating on concrete walls in a wastewater treatment plant only two months after installation Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31893 [article]

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Ceramic epoxy coatings in immersion / Ben Rowland in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 9 (09-10/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 9 (09-10/2018) . - p. 32-34 Titre : Ceramic epoxy coatings in immersion Type de document : texte imprimé Auteurs : Ben Rowland, Auteur Année de publication : 2018 Article en page(s) : p. 32-34 Langues : Américain (ame) Catégories : Adhésion Anticorrosion Essais dynamiques Immersion Perméabilité Pliage (mécanique) Réservoirs (récipients) -- revêtements protecteurs Revêtement de céramique Revêtements -- Propriétés mécaniques Revêtements protecteurs Tuyauterie -- Protection Index. décimale : 667.9 Revêtements et enduits Résumé : Having been used on over 50-million linear feet of ductile iron wastewater pipe and in potable water storage tanks for almost four decades, ceramic pigments in coatings have provided superior corrosion protection for substrates in immersion in water and wastewater applications (Figs. 3 and 4). Conventional immersion coating systems offer a wide variety of features that are benefical in preventing corrosion in immertion applications, but few offer as many features as do ceramic epoxy coating systems. The fact that ceramic epoxies are less expensive than traditional products coupled with their ability. Note de contenu : - What is a ceramic epoxy coating ? - Ceramic epoxies versus traditional epoxies - High-film build - Permeability - Adhesion versus cohesion - Flexibility - Fig. 1 : Application of ceramic epoxy coating - Fig. 2 : A mandrel bend test was conducted as per ASTM D522, "Standard test methods for mandrel bend test of attached organics coatings" to determine the ceramic epoxy coating's elongation or flexibility - Fig. 3 : A 1,5-million-gallon ground water storage tank in Alabama lined with ceramic epoxy - Fig. 4 : Ductile iron pipe lined with ceramic epoxy Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31896 [article]

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The effect of caustic soda solutions on fusion-bonded epoxy coatings at high temperatures / Hassan Al-Sagour in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 9 (09-10/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 9 (09-10/2018) . - p. 36-43 Titre : The effect of caustic soda solutions on fusion-bonded epoxy coatings at high temperatures Type de document : texte imprimé Auteurs : Hassan Al-Sagour, Auteur ; Mana Al-Mansour, Auteur Année de publication : 2018 Article en page(s) : p. 36-43 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Adhésion Analyse spectrale Analyse thermique Calorimétrie Décoloration Diffractométrie de rayons X Epaisseur -- Mesure Essais (technologie) Hydroxyde de sodium L'hydroxyde de sodium, appelé également soude caustique7, est un corps chimique composé minéral de formule chimique NaOH, qui est à température ambiante un solide ionique. Fusible vers 318 °C, il se présente généralement sous forme de pastilles, de paillettes ou de billes blanches ou d'aspect translucide, corrosives et très hygroscopiques. Il est très soluble dans l'eau et légèrement soluble dans l'éthanol. La solution d'hydroxyde de sodium, souvent appelée soude, est une solution aqueuse transparente. Concentrée, elle est corrosive et souvent appelée lessive de soude. Les propriétés chimiques de l'hydroxyde de sodium sont surtout liées à l'ion hydroxyde HO- qui est une base forte. En outre, l'hydroxyde de sodium réagit avec le dioxyde de carbone (CO2) de l'air et se carbonate. La solubilité de la soude caustique dans l'eau augmente avec la température, à pression constante ou ambiante. Résistance chimique Revêtement époxy lié par fusion Revêtements -- Analyse Index. décimale : 667.9 Revêtements et enduits Résumé : In the article, "Qualification test for high-temperature FBE coatings" in the July 2018 issue of JPCL, the results of qualification testing of high-temperature fusion-bonded epoxy (FBE) coatings were reported by the authors. This testing involved immersion in different solutions at a high temperature to examine the chemical resistance of various FBE coatings. Three candidate products were immersed at a high temperature and all showed satisfactory performance in distilled water, synthetic sea water and a 5-precent NaCl solution. Most products, however experienced serve discoloration when immersed in a 5-precent NaOH (causic soda) solution. In this article the authors describe further testing conducted on one of the candidate products to determine the significance of this discoloration. While it is common in the coating industry to condiser discolorationa failure, discoloration has sometimes been claimed a result of the reaction between coloring pigments and test solutions indicating no impact on a coating's properties. Hence, this work has been carried out to more closely examine the source of color change and address the changes in coating properties in more detail. Note de contenu : - The background - Microscopic examination - Dry-film thickness - Pull-off adhesion - Electrochemical impedance spectroscopy - X-ray diffraction - Energy dispersive X-ray spectroscopy - Differential scanning calorimetry - Attenuated total reflectance fourier spectroscopy - Fig. 1 : Cross-section examinqtion qt 80-times magnification. Figures counrtnesy of the author. - Fig. 2 : Color, DFH and adhesion on Sample 1. - Fig. 3 : Color, DFH and adhesion on Sample 2. - Fig. 4 : Color, DFH and adhesion on Sample 3. - Fig. 5 : DSC scans from panels after immersion in different solutions. - Fig. 6 : DSC scan of the coating after dry heat. - Table 1 : DFT, Adhesion and EIS before and after immersion in NaOH solution. - Table 2 : Composition of the top layer. - Table 3 : Composition of the intermediate layer. - Table 4 : Elemental composition comparison (EDX vs. XRD) Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31897 [article]

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