ISSN:
1662-9752
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
In order to clarify the failure behavior of plasma sprayed thermal barrier coating (TBC)systems under the complicated modes of thermal-mechanical-chemical loadings, the stress ruptureproperty evaluation and failure analysis were conducted for Y2O3-ZrO2 (YSZ) and CaO-SiO2-ZrO2(C2S-CZ) TBC systems in air and two kinds of high-temperature corrosive environments.Static creep loading was found to bring about the typical creep failure for TBC systems even in theaggressive environment so called hot corrosion almost in similar manner to the case in air. On thecontrary, it was revealed that the dynamic fatigue loading tends to cause a significant failure lifereduction of TBC systems both in air and in corrosive environments. For YSZ TBC system, thepenetration crack preexisting through the top-coat layer tends to provide a nucleation site for thefatigue crack even in air, and more significantly a short circuit path for the corrosive species in hotcorrosive environment. For C2S-CZ system, on the contrary, the top-coat / bond-coat interface tendsto provide easily the nucleation site for a main crack to propagate thereafter toward both the alloyinterior and outer surface. Under lower stress level at 950ºC, however, the oxide-induced crackclosure together with crack tip blunting attributed mainly to the high reactivity of Ca compounds as amajor constituent of the TC is effective to suppress substantially the crack propagation, so as to causethe prolonged failure life as compared to YSZ system even in aggressive gaseous environment
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.522-523.353.pdf
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