| Summary: | Since the introduction of electron beam
(EB) physical vapour deposition (PVD) thermal
barrier
coatings (TBCs) and their application to moving components in the hot gas
stream, erosion has become a prime concern. EB PVD TBCs, due to their unique
columnar microstructure are far more strain tolerant than their plasma sprayed (PS)
counter
parts and can thus be used under more exacting operating conditions. It is under
these
operating conditions that erosion of the coated components is of primary
importance.
The main aim of this
project was the development of a computer model capable of
predicting the erosion rate of EB PVD TBCs under various different conditions. I
order to do this it was first
necessary to determine the erosion mechanisms of EB PVD
TBCs as well as their mechanical
properties. Steady state erosion and single impact
studies
together with SEM were used to determine the erosion mechanisms, while nano
indentation
techniques were used to obtain the hardness and the Youngs Modulus of the
EB PVD TBC. Literature searches contributed to the
understanding of erosion
principles and factors affecting erosion.
All these
findings were then used in the development of a Monte-Carlo type
computational erosion model capable of predicting the erosive wear rate of EB PVD
TBCs under various conditions. The model which has been
developed' is capable of
predicting the erosion rate of EB PVD TBC to within 30%, so long as the erosion falls
within a certain defined mechanism, which can easily be checked against a erosion
map, which has been drawn.
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