Effect of coating structure on the adherence of sputter-deposited oxide coatings. [ZrO/sub 2/-Y/sub 2/O/sub 3/; Al/sub 2/O/sub 3/-Cr/sub 2/O/sub 3/]

Conference · Fri Apr 01 04:00:00 EST 1983

OSTI ID:6016928

Prater, J T; Moss, R W

Evaluation of ceramic coatings with graded metal-to-ceramic transition zones and columnar ceramic structures have been completed. The ceramic materials investigated were ZrO/sub 2/.20 Y/sub 2/O/sub 3/, ZrO/sub 2/.8 Y/sub 2/O/sub 3/ and Al/sub 2/O/sub 3/.40 Cr/sub 2/O/sub 3/ deposited over NiCrAlY and CoCrAlY bond layers. Dense ceramic closeout layers were deposited over the columnar ceramic to reduce coating permeability. The majority of the zirconia coatings failed as a result of massive diffusion of aluminum (MCrAlY) and oxygen (ZrO/sub 2/) in the graded metal-ceramic layer. Coating fracture occurred very low in the graded transition zone where a band of Al/sub 2/O/sub 3/ and voids formed. These acted as a preferred path for crack propagation. For this reason, the ZrO/sub 2/ coating which had no graded transition zone performed best in thermal-cycling experiments. Graded Al/sub 2/O/sub 3/ - CoCrAlY layers were less affected by interdiffusion. However, deposition of ceramic layers of Al/sub 2/O/sub 3/.40 Cr/sub 2/O/sub 3/ or ZrO/sub 2/.20 Y/sub 2/O/sub 3/ over graded Al/sub 2/O/sub 3/ - CoCrAlY layers displayed poor adherence.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6016928
• Report Number(s): PNL-SA-10842; CONF-830443-3; ON: DE83011804
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360200* -- Ceramics
Cermets
& Refractories
ADHESION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
COATINGS
CRACK PROPAGATION
FAILURES
FRACTURES
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES