Plasma-spray coated rare-earth oxides on molybdenum disilicide - High temperature stable emitters for thermophotovoltaics

Selective emitters for thermophotovoltaics consisting of intermetallic alloy MoSi2 substrate with plasma-spray coated rare-earth oxides ytterbium oxide Yb2O3, Yb-doped garnet Yb1.5Y1.5Al5O12, and erbium oxide Er2O3 have been successfully tested till 1650 degrees C. The emitters are fully operable in an oxygen containing atmosphere, are highly thermal shock stable, and show good selective emitting properties. Shielding the high out-of-band emittance of the MoSi2 substrate with a 4 mu m thick Pt intermediate layer has resulted in reduced radiation power and emittance of the rare-earth oxide film due to multiple reflections at the interfaces. The novel technique of vacuum plasma-spray coated rare-earth oxide films on MoSi2 is a promising way for the production of effective and high temperature stable selective thermophotovoltaic emitters. (C) 2007 Elsevier Ltd. All rights reserved.