TY - JOUR
T1 - Process-structure-property relations for the erosion durability of plasma spray-physical vapor deposition (PS-PVD) thermal barrier coatings
AU - Schmitt, Michael P.
AU - Harder, Bryan J.
AU - Wolfe, Douglas E.
N1 - Funding Information:
The authors would like to thank Dr. Rick Rogers and Dr. Brian Good for their thoughtful discussion. This work was supported under the NASA Graduate Student Researchers Program (GSRP) award No. NNX11AL02H and the Applied Resarch Lab (ARL)-Walker Fellowship program . The opinions and views expressed are those of the authors and do not necessarily reflect NASA or the US Navy.
Publisher Copyright:
© 2015.
PY - 2016/7/15
Y1 - 2016/7/15
N2 - New thermal barrier coating (TBC) materials and microstructures are under development to increase gas turbine operating temperatures beyond the ~1200 °C threshold of standard 7 wt.% yttria stabilized zirconia (7YSZ). To deposit these advanced coatings, a new thermal spray deposition technique is used: Plasma Spray - Physical Vapor Deposition (PS-PVD). PS-PVD is capable of depositing from the vapor phase to yield strain tolerant columnar microstructures similar to Electron Beam - Physical Vapor Deposition (EB-PVD) or, alternatively, the traditional splat-like lamellar microstructure common to Air Plasma Spray (APS). This study investigates the process-structure relationships and resulting erosion response for plasma gas flow, amperage, and feed rate. It was found that in the selected design space, porosity and surface roughness vary from ~12-26% and ~5-10 μm, respectively. Erosion behavior is discussed and the mechanism is identified to be heavily dependent upon the intercolumnar spacing. The lowest erosion rates are similar to EB-PVD, while the highest erosion rates were closer to APS. This is attributed to the hybrid nature of the PS-PVD process and provides an opportunity to tailor coatings with a wide range of properties, and thus performance.
AB - New thermal barrier coating (TBC) materials and microstructures are under development to increase gas turbine operating temperatures beyond the ~1200 °C threshold of standard 7 wt.% yttria stabilized zirconia (7YSZ). To deposit these advanced coatings, a new thermal spray deposition technique is used: Plasma Spray - Physical Vapor Deposition (PS-PVD). PS-PVD is capable of depositing from the vapor phase to yield strain tolerant columnar microstructures similar to Electron Beam - Physical Vapor Deposition (EB-PVD) or, alternatively, the traditional splat-like lamellar microstructure common to Air Plasma Spray (APS). This study investigates the process-structure relationships and resulting erosion response for plasma gas flow, amperage, and feed rate. It was found that in the selected design space, porosity and surface roughness vary from ~12-26% and ~5-10 μm, respectively. Erosion behavior is discussed and the mechanism is identified to be heavily dependent upon the intercolumnar spacing. The lowest erosion rates are similar to EB-PVD, while the highest erosion rates were closer to APS. This is attributed to the hybrid nature of the PS-PVD process and provides an opportunity to tailor coatings with a wide range of properties, and thus performance.
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U2 - 10.1016/j.surfcoat.2016.04.029
DO - 10.1016/j.surfcoat.2016.04.029
M3 - Article
AN - SCOPUS:84964533660
SN - 0257-8972
VL - 297
SP - 11
EP - 18
JO - Surface and Coatings Technology
JF - Surface and Coatings Technology
ER -