Emissivity enhancement coatings for thermophotovoltaic (TPV) radiator applications

Technical Report · Tue Dec 01 04:00:00 EST 1998

DOI:https://doi.org/10.2172/677064· OSTI ID:677064

Yue, J J; Cockeram, B V

Ten emissivity enhancing coatings (ZrO{sub 2} + 18% TiO{sub 2} + 10% Y{sub 2}O{sub 3}, Cr{sub 2}O{sub 3}, ZrC, Fe{sub 2}TiO{sub 5}, ZrTiO{sub 4}, ZrO{sub 2} + 8% Y{sub 2}O{sub 3} + 2% HfO{sub 2}, TiC, TiC + 5% Al{sub 2}O{sub 3} + 5% TiO{sub 2}, ZrB{sub 2}, and ZrB{sub 2} + 10% MoSi{sub 2}) deposited on Mo, Nb, and Haynes 230 substrates were evaluated for potential use in thermophotovoltaic (TPV) radiator applications. Emissivity testing of as-coated and annealed coupons indicate that 5 of the 10 Vacuum Plasma Spray (VPS) coating candidates have promise (ZrO{sub 2} + 18% TiO{sub 2} + 10% Y{sub 2}O{sub 3}, ZrC, Fe{sub 2}TiO{sub 5}, ZrTiO{sub 4}, ZrO{sub 2} + 8% Y{sub 2}O{sub 3} + 2% HfO{sub 2}). Four of the ten coatings have emissivity values that are too low to be of further interest (TiC, TiC + 5% Al{sub 2}O{sub 3} + 5% TiO{sub 2}, ZrB{sub 2}, and ZrB{sub 2} + 10% MoSi{sub 2}). The final coating was mostly Cr{sub 2}O{sub 3}, and exhibited excessive evaporation during vacuum annealing with a significant decrease in emissivity. Base metal powder, which was added to the bond layer of all coatings to improve coating adhesion, was detected in the top layer of the coatings. Differences in reactive interaction between the base metal powder and coating during vacuum annealing produced varying changes in emissivity. A small decrease in emissivity was observed for the ZrC coating deposited on niobium, which agrees with the limited interaction between the niobium base metal particles and the ZrC coating detected in SEM/EDS examinations. A large decrease in emissivity was observed for the ZrC coating deposited on Haynes 230, and significant interaction between the base metal particles and ZrC coating was observed.

• Research Organization: Bettis Atomic Power Lab., West Mifflin, PA (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
• DOE Contract Number: AC11-93PN38195
• OSTI ID: 677064
• Report Number(s): WAPD-T--3235; ON: DE99000517
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CHROMIUM OXIDES
EMISSIVITY
EXPERIMENTAL DATA
HAFNIUM OXIDES
IRON OXIDES
MOLYBDENUM SILICIDES
SPRAYED COATINGS
THERMOPHOTOVOLTAIC CONVERTERS
TITANIUM CARBIDES
TITANIUM OXIDES
YTTRIUM OXIDES
ZIRCONIUM BORIDES
ZIRCONIUM CARBIDES
ZIRCONIUM OXIDES