ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
MCrAlY-typed coatings are conventional for applications to land-based turbines against hightemperatureoxidation and corrosion. However, improvements are still currently expected frominnovations in the coating process and/or in the selection of the starting materials. Both types ofinnovations were studied in the present work. The former consisted in cold spray as a substitutefor plasma spray which is conventionally used as the coating process. The latter consisted indeveloping mechanically-alloyed powders to be suitable for the targeted application especially.In this study, coating-substrate adhesion was considered as the justice of the peace to assessimprovements from these innovations. This was determined using the LAser Shock AdhesionTest, namely LASAT, which was recently developed as innovative adhesion testing of thermalspray coatings.Among the main results, mechanical alloying was shown to be satisfactory to result in anhomogeneous powder from the mixing of CoNiCrAlY with Mo. This powder could be coldsprayed,all the more easily because of a fine grain size. Results were compared with thoseobtained from conventional commercial pre-alloyed powders. As a general result, it was shownthat cold spray could lead to highly-dense and high-adhesion MCrAlY-typed coatings ontoInconel 625 even though the process is usually claimed to be convenient for high-ductilitymaterials such as copper. Incidentally, LASAT was confirmed to be a flexible and powerfultesting tool to study adhesion; which resulted in the ranking of the various types of coatingsinvolved in the work. Results are discussed in the light of an experimental simulation of theimpinging of cold-sprayed particles using so-called “laser flier impact experiments”. In thisdevelopment of this simulation approach to cold spray, the flier was made of a 50μm-thick discmachined from HIP’ed CoNiCrAlY
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.1086.pdf
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