Coating maintenance planning to ensure reliable water and power delivery / Bobbi Jo E. Merten in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 31, N° 5 (05/2014)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 31, N° 5 (05/2014) . - p. 52-61 Titre : Coating maintenance planning to ensure reliable water and power delivery Type de document : texte imprimé Auteurs : Bobbi Jo E. Merten, Auteur ; Richard Pepin, Auteur ; David Tordonato, Auteur ; allen Skaja, Auteur Année de publication : 2014 Article en page(s) : p. 52-61 Langues : Américain (ame) Catégories : Entretien et réparations Planification stratégique Tuyauterie Tuyaux d'eau Index. décimale : 667.9 Revêtements et enduits Résumé : The Bureau of Reclamation is responsible for delivering raw water and power in the country's 17 western states. Reclamation infrastructure provides irrigation water to 25% and 60% of the nation's fruit and vegetable rrops, respectively. This water also reaches 31 million people for municipal, residential, and industrial uses. In addition, Reclamation contributes to 17% of nation's hydropower through 53 owned and operated hydroelectric power plants, including the Grand Coulee Dam in Washington, the Hoover Dam in Nevada, and the Buffalo Bill Dam in Wyoming. It is vital to ensure that this water and power delivery is continued and reliable. The successful operation of this very large and complex infrastructure requires careful coating maintenance planning. Reclamation's assets include small to extremely large facilities ; hard-to-access areas such as confined spaces, remote locations, and rough and steep terrain ; and atmospheric, immersion, or fluctuating immersion exposure conditions. Each scenario affects the maintenance plan, and creative solutions are often required to arrive at a cost-effective approach. This article describes the strategies used by Reclamation's facility personnel and coatings specialists to inspect, repair, and recoat coated infrastructure. The authors conclude with basic details one should consider when developing a coatings maintenance strategy. Note de contenu : - HYDROPOWER FACILITIES - COATINGS INSPECTION - MAINTENANCE OPTIONS : Deferral of maintenance - Spot repairs - Spot repairs with full overcoat(s) - Total removal and replacement - THE IDEAL MAINTENANCE - COATINGS MAINTENANCE PROJECT PROGRESSION : Scope definition - Coatings specification - Construction support - RECLAMATION'S COATINGS MAINTENANCE CHALLENGES - DEVELOPING A COATINGS MAINTENANCE STRATEGY Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21644 [article]

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Laboratory evaluation of metalized coatings for use on reclamation infrastructure / David Tordonato in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 30, N° 11 (11/2013)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 30, N° 11 (11/2013) . - p. 22-33 Titre : Laboratory evaluation of metalized coatings for use on reclamation infrastructure Type de document : texte imprimé Auteurs : David Tordonato, Auteur ; allen Skaja, Auteur Année de publication : 2013 Article en page(s) : p. 22-33 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acier L'acier est un alliage métallique utilisé dans les domaines de la construction métallique et de la construction mécanique. L'acier est constitué d'au moins deux éléments, le fer, très majoritaire, et le carbone, dans des proportions comprises entre 0,02 % et 2 % en masse1. C'est essentiellement la teneur en carbone qui confère à l'alliage les propriétés du métal qu'on appelle "acier". Il existe d’autres métaux à base de fer qui ne sont pas des aciers comme les fontes et les ferronickels par exemple. Aluminium L'aluminium est un élément chimique, de symbole Al et de numéro atomique 13. C’est un métal pauvre, malléable, de couleur argent, qui est remarquable pour sa résistance à l’oxydation13 et sa faible densité. C'est le métal le plus abondant de l'écorce terrestre et le troisième élément le plus abondant après l'oxygène et le silicium ; il représente en moyenne 8 % de la masse des matériaux de la surface solide de notre planète. L'aluminium est trop réactif pour exister à l'état natif dans le milieu naturel : on le trouve au contraire sous forme combinée dans plus de 270 minéraux différents, son minerai principal étant la bauxite, où il est présent sous forme d’oxyde hydraté dont on extrait l’alumine. Il peut aussi être extrait de la néphéline, de la leucite, de la sillimanite, de l'andalousite et de la muscovite. L'aluminium métallique est très oxydable, mais est immédiatement passivé par une fine couche d'alumine Al2O3 imperméable de quelques micromètres d'épaisseur qui protège la masse métallique de la corrosion. On parle de protection cinétique, par opposition à une protection thermodynamique, car l’aluminium reste en tout état de cause très sensible à l'oxydation. Cette résistance à la corrosion et sa remarquable légèreté en ont fait un matériau très utilisé industriellement. L'aluminium est un produit industriel important, sous forme pure ou alliée, notamment dans l'aéronautique, les transports et la construction. Sa nature réactive en fait également un catalyseur et un additif dans l'industrie chimique ; il est ainsi utilisé pour accroître la puissance explosive du nitrate d'ammonium. Anticorrosion Essais accélérés (technologie) Essais d'adhésion Etanchéité Métaux -- Revêtements protecteurs Projection thermique Revêtement métallique Revêtements:Peinture Test d'immersion Index. décimale : 667.9 Revêtements et enduits Résumé : Five thermal spray alloys and two sealers were investigated using laboratory testing that included immersion, accelerated weathering, and adhesion. All the coating systems tested appear to offer some degree of corrosion protection to the steel substrate ; the unscribed and undamaged areas of all of the plates remained corrosion free throughout the test. However, problems were noted with some systems, such as blistering, application difficulties, and excessive weight loss during testing. The following conclusions from this study are offered. • Metalized coatings may provide a significant life-cycle cost advantage over organic coatings on equipment subject to fluctuating immersion such as radial gates, stoplogs, and partially exposed trashracks. Conventional organic coatings have a shorter service life in fluctuating immersion environments. Metalized coatings are superior to polymer coatings when rapid return to service is needed, during cold weather applications, or where VOC emissions are restricted. Metalizing is not compatible with impressed-current CP systems. • The service life of all metalized coating systems will depend heavily on factors related to the service environment, such as immersion duration and frequency, as well as water chemistry. Avoid using zinc or aluminum in immersion environments with extreme pH (below 6 or above 12). The use of zinc should also be avoided in flowing water. • Of the systems tested, the pure aluminum system is believed to offer the best combination of corrosion protection and expected service life in immersion or fluctuating immersion. In addition, aluminum is easy to apply, is relatively low in cost, and exhibited greater adhesion strengths compared to the other systems. • Aluminum systems appear to offer good general corrosion pro-tection to steel but reduced CP to areas where the coating is dam-aged, especially in water with low levels of conductivity, i.e., reser-voirs fed by snowmelt. • Further research and evaluation are needed to accurately deter-mine an expected service life, determine case to repair defects, and determine a method to deal with crevice corrosion. • Due to blistering, ZA and AM systems are not recommended on equipment where immersion is likely. • Zn/A1 appears to produce an oxide that is more stable than that of pure zinc. The samples lost no weight during testing, and visible corrosion was less than what was observed in the other unsealed panels. These results warrant investigation into a modified Zn/A1 alloy that produces a stable oxide without blistering in immersion. • The AA samples produced significant amounts of oxidation reactants that tended to be dispersed ran-domly on the plate rather than uniformly. Furthermore, the material was more diffi-cult and expensive to apply and offered no performance advantage over pure alu-minum in terms of corrosion protection. Both scalants tested offer increased corro-sion protection when applied with sufficient DFT. However, both sealants are susceptible to degradation from UV light. In addition, the use of a sealer removes some of the advantages of TSCs, such as immediate return to service, fast application, and fewer restrictions on environmental conditions. Note de contenu : - METALIZED COATING TESTING - METALIZING CASE STUDIES AND EXAMPLES : Atmospheric exposure - Immersion and fluctuating freshwater immersion - Methodology - RESULTS : Weight change - Adhesion test results - GENERAL CORROSION PROTECTION : Effect of test - Effect of alloy - Effect of seal coat - Blistering - Other considerations - Safety Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20721 [article]

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Mechanical property changes and degradation during accelerated weathering of polyester-urethane coatings / allen Skaja in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 3, N° 1 (01/2006)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 3, N° 1 (01/2006) . - p. 41-51 Titre : Mechanical property changes and degradation during accelerated weathering of polyester-urethane coatings Type de document : texte imprimé Auteurs : allen Skaja, Auteur ; Dilhan Fernando, Auteur ; Stuart G. Croll, Auteur Année de publication : 2006 Article en page(s) : p. 41-51 Note générale : bibliogr. Langues : Américain (ame) Tags : Vieillissement  physique  Propriété  mécanique  chimique  Structure  moléculaire  Etude  expérimentale  Durabilité  Uréthanne  polymère  produit  Résistance  intempérie  Dégradation  photochimique  Mécanisme  réaction  Relaxation  structurale  Densité  réticulation  Matériau  revêtement  Esteruréthanne  accéléré  Temps  exposition  Module  élasticité Index. décimale : 667.9 Revêtements et enduits Résumé : Chemical changes, measured using spectroscopy, and crosslink density, measured by mechanical thermal analysis, were determined during accelerated weathering on a model polyester-urethane coating of known composition. The tensile modulus, measured above the glass transition temperature, and thus the crosslink density, decreased with exposure, as expected from the chemical changes. However, the tensile modulus, measured at room temperature, increased with exposure. Physical aging of the polymer network was found to occur concurrently with photodegradation and accounts for much of the increase in room temperature modulus. Increased hydrogen bonding in the increasingly oxidized polyester-urethane may also contribute to the increase in modulus at room temperature. Both physical and chemical changes must be determined if changes, and rates of change, in performance due to weathering are to be understood. DOI : 10.1007/s11998-006-0004-7 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-006-0004-7.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3711 [article]

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