Comparative study of EB-PVD gadolinium-zirconate and yttria-rich zirconia coatings performance against Fe-containing calcium-magnesium-aluminosilicate (CMAS) infiltration

Calcium-Magnesium-Aluminosilicate (CMAS) Reactions and Degradation Mechanisms of Advanced Environmental Barrier Coatings

The thermochemical reactions between calcium-magnesium-aluminosilicate(CMAS-) based road sand and several advanced turbine engine environmnetal barrier coating (EBC) materials were studied. The phase stability, reaction kinetics and degradation mechanisms of rare earth (RE)-silicates Yb2SiO5, Y2Si2O7, and RE-oxide doped HfO2 and ZrO2 under the CMAS infiltration condition at 1500 C were investi...

WEAR REESISTANCE OF NANOSTRUCTURED AND CONVENTIONAL YTTRIA-STABILIZED ZIRCONIA COATINGS

Partially stabilized zirconia (PSZ) has been proven to be an excellent candidate as a thermal barrier coating (TBe) for hot sections in, for instance, heat or internal combustion engines and gas turbine parts. The main functions of these coatings are reducing heat losses, reducing fuel consumption, increasing efficiency, and extending durability and life. One of the main problems involved is we...

Morphology and thermal conductivity of yttria-stabilized zirconia coatings

An electron beam directed vapor deposition method was used to grow 7 wt.% Y2O3–ZrO2 (7YSZ) coatings and the effects of substrate rotation upon the coating porosity, morphology, texture, and thermal conductivity were explored. As the rotation rate was increased, the texture changed from Æ111æ to Æ100æ. Under stationary deposition, the coatings were composed of straight columns, while low-frequen...

Erosion, Corrosion and Erosion-Corrosion of EB PVD Thermal Barrier Coatings

Electron beam (EB) physical vapour deposited (PVD) thermal barrier coatings (TBCs) have been used in gas turbine engines for a number of years. The primary mode of failure is attributed to oxidation of the bondcoat and growth of the thermally grown oxide (TGO), the alumina scale that forms on the bondcoat and to which the ceramic top coat adheres. Once the TGO reaches a critical thickness the T...

CMAS Corrosion of EB PVD TBCs: Identifying the Minimum Level to Initiate Damage