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Microstructural investigation of PGM-based alloy coatings for oxidation protection / Y. Song in Materials and corrosion, Vol. 62 N° 7 (Juillet 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 7 (Juillet 2011) . - pp. 674–680 Titre : Microstructural investigation of PGM-based alloy coatings for oxidation protection Type de document : texte imprimé Auteurs : Y. Song, Auteur ; C. Zhou, Auteur ; H. Murakami, Auteur Année de publication : 2011 Article en page(s) : pp. 674–680 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cyclic  oxidation  Pt/Ir-modified  Pt/Ru-modified Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : It is well known that Pt addition significantly improves the resistance of aluminide coatings to high-temperature oxidation and hot corrosion, which has led to the widespread application of Pt modified aluminide coatings on the superalloy components of advanced gas turbine engines. Other platinum group metals (PGMs) such as Ir and Ru attract researchers for high temperature applications. In this study, oxidation properties of Pt-Ir and Pt-Ru based alloy coatings were investigated. Pt, Ru, and Ir were electroplated on a directionally solidified Ni-base superalloy DZ125. The cyclic oxidation test revealed that both Pt-Ir and Pt-Ru alloys exhibited good oxidation performance. The effect of substrate alloy and coating compositions on microstructural changes during cyclic oxidation tests were discussed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005877/abstract [article] Microstructural investigation of PGM-based alloy coatings for oxidation protection [texte imprimé] / Y. Song, Auteur ; C. Zhou, Auteur ; H. Murakami, Auteur . - 2011 . - pp. 674–680. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 7 (Juillet 2011) . - pp. 674–680 Mots-clés : Cyclic  oxidation  Pt/Ir-modified  Pt/Ru-modified Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : It is well known that Pt addition significantly improves the resistance of aluminide coatings to high-temperature oxidation and hot corrosion, which has led to the widespread application of Pt modified aluminide coatings on the superalloy components of advanced gas turbine engines. Other platinum group metals (PGMs) such as Ir and Ru attract researchers for high temperature applications. In this study, oxidation properties of Pt-Ir and Pt-Ru based alloy coatings were investigated. Pt, Ru, and Ir were electroplated on a directionally solidified Ni-base superalloy DZ125. The cyclic oxidation test revealed that both Pt-Ir and Pt-Ru alloys exhibited good oxidation performance. The effect of substrate alloy and coating compositions on microstructural changes during cyclic oxidation tests were discussed. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005877/abstract

Novel processing in inert atmosphere and in air to manufacture high-activity slurry aluminide coatings modified by Pt and Pt/Ir / M. C. Galetz in Materials and corrosion, Vol. 63 N° 10 (Octobre 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 10 (Octobre 2012) . - pp. 921–928 Titre : Novel processing in inert atmosphere and in air to manufacture high-activity slurry aluminide coatings modified by Pt and Pt/Ir Type de document : texte imprimé Auteurs : M. C. Galetz, Auteur ; X. Montero, Auteur ; H. Murakami, Auteur Année de publication : 2013 Article en page(s) : pp. 921–928 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Air;  aluminide;  iridium;  platinum;  slurry Résumé : Slurry-derived coatings are an interesting alternative method to pack aluminization of nickel-base superalloys, which provide similar properties and protection at high temperatures. For highest performance, these aluminide coatings are modified by the addition of Pt or, as recent research suggests, with Pt/Ir. While the combination of Pt and Pt/Ir with an out-of-pack process is state of the art, slurry coatings are of special interest as a repair method for turbine blades. In this study, the microstructural evolution of slurry-derived coatings manufactured on CM 247 in inert atmosphere as well as in air was investigated. Layers of Ni, Pt, and Pt/Ir mixtures were electrodeposited. After annealing, a diffusion heat-treatment with a slurry containing aluminum or aluminum–silicon powder was applied on the samples. The addition of silicon is well known to be beneficial for hot corrosion environments. The reaction and interdiffusion behavior of aluminum/aluminum–silicon determines the microstructural evolution of the coatings. Depending on the initial electroplated layer on the surface, different microstructures can be obtained, such as the Pt/Ir-modified beta phase (Ni,Pt)Al or two-phase layers of PtAl2 and NiAl. Additionally, the reactivity between the elements at the surface and those from the slurry was shown to determine homogeneity and surface roughness of the diffusion coating, also depending on the atmosphere used during slurry aluminization. Finally, it was demonstrated that iridium has a high influence on the diffusion behavior and especially the distribution of platinum in the coatings. Such new coatings have the potential to overcome some disadvantages of conventionally manufactured high-activity aluminide coatings, as the combination of Pt/Ir-electroplating with the slurry process results in less detrimental substrate elements like molybdenum or tungsten close to the surface. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206773/abstract [article] Novel processing in inert atmosphere and in air to manufacture high-activity slurry aluminide coatings modified by Pt and Pt/Ir [texte imprimé] / M. C. Galetz, Auteur ; X. Montero, Auteur ; H. Murakami, Auteur . - 2013 . - pp. 921–928. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 10 (Octobre 2012) . - pp. 921–928 Mots-clés : Air;  aluminide;  iridium;  platinum;  slurry Résumé : Slurry-derived coatings are an interesting alternative method to pack aluminization of nickel-base superalloys, which provide similar properties and protection at high temperatures. For highest performance, these aluminide coatings are modified by the addition of Pt or, as recent research suggests, with Pt/Ir. While the combination of Pt and Pt/Ir with an out-of-pack process is state of the art, slurry coatings are of special interest as a repair method for turbine blades. In this study, the microstructural evolution of slurry-derived coatings manufactured on CM 247 in inert atmosphere as well as in air was investigated. Layers of Ni, Pt, and Pt/Ir mixtures were electrodeposited. After annealing, a diffusion heat-treatment with a slurry containing aluminum or aluminum–silicon powder was applied on the samples. The addition of silicon is well known to be beneficial for hot corrosion environments. The reaction and interdiffusion behavior of aluminum/aluminum–silicon determines the microstructural evolution of the coatings. Depending on the initial electroplated layer on the surface, different microstructures can be obtained, such as the Pt/Ir-modified beta phase (Ni,Pt)Al or two-phase layers of PtAl2 and NiAl. Additionally, the reactivity between the elements at the surface and those from the slurry was shown to determine homogeneity and surface roughness of the diffusion coating, also depending on the atmosphere used during slurry aluminization. Finally, it was demonstrated that iridium has a high influence on the diffusion behavior and especially the distribution of platinum in the coatings. Such new coatings have the potential to overcome some disadvantages of conventionally manufactured high-activity aluminide coatings, as the combination of Pt/Ir-electroplating with the slurry process results in less detrimental substrate elements like molybdenum or tungsten close to the surface. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206773/abstract