Directionally solidified fabrication in planar geometry of Al_2O_3-Er_3Al_5O_12 eutectic composite for thermophotovoltaic devices

Abstract

Abstract:In this work Al 2 O 3 -Er 3 Al 5 O 12 eutectic composite was manufactured in planar geometry departing from eutectic particles both produced by directional solidification using a CO 2 laser system at rates of 180 and 720 mm/h. Microstructure and mechanical properties were investigated as a function of the growth rate. Homogeneous and interpenetrated microstructure was found with phase size strongly dependent on the growth rate, decreasing when the processing rate was increased. Thermal emission of eutectic composites was studied in function of thermal excitation by using CO 2 laser radiation as a heating source. An intense narrow emission band at 1.55 µm matching with the sensitive region of the InGaAs photoconverter and a low emission band at 1 µm were obtained. Features of thermal emission bands were correlated with collecting angle, microstructure and laser power, and compared to those obtained from departing eutectic particles.

Directionally solidified Ni doped MgO-MgSZ eutectic composites for thermophotovoltaic devices

“…Directionally Solidified Eutectic (DSE) ceramics are particularly interesting for TPV devices due to their outstanding mechanical properties, microstructure stability, and corrosion resistance up to temperatures very close to their melting point [10], which make them suitable for the extreme conditions of operation of the TPV converters. Recently, the incorporation of rare-earth ions to Al 2 O 3 -based eutectics [11][12][13][14] has allowed obtaining selective emitters fulfilling the TPV requirements. The main disadvantage of the use of rare-earth ion selective emitters is that their thermal emissions consist of very narrow bands corresponding to the 4f electronic transitions, which results in low power densities unless very high temperatures are used.…”

Nanocrystalline Alumina-Zirconia-Based Eutectic Ceramics Fabricated with High-Energy Beams: Principle, Solidification Techniques, Microstructure and Mechanical Properties

“…There are several available methods, which have been developed in the past, that can be adopted to solidify alumina-based nanoeutectic ceramics in the laboratory, such as laserheated float zoning (LFZ) [8,13,14,26,[28][29][30]32,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53], micro-pulling-down (µ-PD) [23,54], aero-acoustic levitators [55], high-energy density beam (HEDB) (laser or oxy-acetylene flame) surface (zone) (re)melting [24,33,[56][57][58][59][60][61][62][63][64][65][66][67][68], plasma spraying [69,70], directed energy deposition (DED)…”

Laser-Induced Breakdown Spectroscopy (LIBS) for Monitoring the Formation of Hydroxyapatite Porous Layers

“…Directionally-solidified eutectic ceramic (DSEC) oxides are composite ceramics obtained departing from a melt. Solidification conditions allow controlling the resulting microstructure and, hence, the material properties, making them suitable for structural and functional applications [11,12,13,14,15,16]. In particular, the CaSiO 3 /Ca 3 (PO 4 ) 2 eutectic composite shows remarkable optical properties.…”