Transmission electron microscope characterization of a plasma-sprayed ZrO{sub 2}-Y{sub 2}O{sub 3}-TiO{sub 2} thermal barrier coating

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · Materials Characterization

DOI:https://doi.org/10.1016/S1044-5803(98)00022-9· OSTI ID:669818

Diaz, P; Ralph, B; Edirisinghe, M J ^[1]

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1. Brunel Univ., Uxbridge (United Kingdom). Dept. of Materials Engineering

Some microstructural elements, such as microtwins in tetragonal ZrO{sub 2} grains (t-ZrO{sub 2}), were identified in a plasma-sprayed ZrO{sub 2}-Y{sub 2}O{sub 3}-TiO{sub 2} coating by using transmission electron microscopy. These elements are similar to those described in plasma-sprayed ZrO{sub 2}-Y{sub 2}O{sub 3} coatings and are characteristic of nontransformable t-ZrO{sub 2}. This microstructure could promote some toughening mechanisms. The monoclinic ZrO{sub 2} phase (m-ZrO{sub 2}), produced by a martensitic transformation of the metastable t-ZrO{sub 2} phase, also was observed. The variation in the concentration of Ti in the ZrO{sub 2}-Y{sub 2}O{sub 3}-TiO{sub 2} coating body was found to be appreciable. The energy-dispersive spectroscopic analyses showed that a high concentration of Ti was associated with t-ZrO{sub 2} whereas a relatively lower content of Ti was found in m-ZrO{sub 2}. ZrO{sub 2}-Y{sub 2}O{sub 3}-TiO{sub 2} thermally treated at 1400 and 1600 C showed signs of grain growth. A higher incidence of m- and t-ZrO{sub 2} twins indicated higher constraints of the polycrystalline structure as a result of the grain growth and rapid cooling rate.

• OSTI ID: 669818
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 2-3 Vol. 41; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL-PHASE TRANSFORMATIONS
GRAIN GROWTH
MICROSTRUCTURE
PLASMA ARC SPRAYING
PROTECTIVE COATINGS
TITANIUM OXIDES
TWINNING
YTTRIUM OXIDES
ZIRCONIUM OXIDES