Structure, optical properties and thermal stability of SS/TiC–ZrC/Al₂O₃ spectrally selective solar absorber

Abstract

A tandem layer structured SS/TiC-ZrC/Al 2 O 3 coating has been prepared by magnetron sputtering for high temperature spectrally selective solar absorber. The coating consists of two layers:TiC-ZrC layer and Al 2 O 3 layer. TiC and ZrC ceramics show the inherent spectral selectivity, which is used to design spectrally selective solar absorber. Co-sputtering technique is used to fabricate the absorptance layer (TiC-ZrC). The coating exhibits a high absorptance of 0.92 and a low emittance of 0.11, as well as an good thermal stability with a selectivity of 0.92/0.13 even after annealing at 700 o C for 100 h in vacuum. The SS/TiC-ZrC/Al 2 O 3 coating also shows good thermal stability at 400 o C for 5 h in air. The surface morphology, composition, structure and optical properties of the coating are characterized using SEM, XPS, XRD, Raman, UV-vis-NIR spectrophotometer and Fourier transform infrared spectroscopy. Benefiting from these advantageous features, the as-deposited SS/TiC-ZrC/Al 2 O 3 coating can be good candidate for the concentrating solar power application.

Ultra-fast green synthesis of a defective TiO2 photocatalyst towards hydrogen production

“…6(d) ), belonging to the C O bonds, O–C–O bonds, C–C bonds and C C bonds, respectively. 70 For the PAs x samples, apart from these four XPS peaks, an additional peak was emerged centered at ∼281.4 eV, corresponding to the Ti–C bonds, 71 confirming the presence of carbonaceous substances in PAs x samples. The portion of XPS spectra related to C C and Ti–C bonds increased as the increased of l -As concentrations, underlining an increased content of carbonaceous substances, reasonably consistent with the Raman and TGA analysis.…”

Structure, optical simulation and thermal stability of the HfB2-based high-temperature solar selective absorbing coatings

“…The calculation method of absorptance (a) and emittance (3) was reported in a previous work. 15 The coatings were annealed in a resistive tube (Hefei Kejing Materials Technology Co., Ltd, China) to test the thermal stability at the temperature range of 400-700 C for 2 h with a pressure of 5.0 Â 10 À1 Pa. Similarly, the long-term thermal stability of the coatings in vacuum and air was investigated for 100 h from room temperature to the desired temperature.…”

Thermal Spray Processes in Concentrating Solar Power Technology

“…Solar properties improved from 0.746/0.161 of the simple only-WC/Co to 0.827/0.145 when Al 2 O 3 powders are added to the WC-Co absorber. The light-trapping effect is improved by increasing the light path inside the materials and the multiple reflections due to the heterogeneity, the multiscale inclusions effect, and alumina optimal optical properties [44,45] (see Figure 8). The ARC Al 2 O 3 led to 0.852/0.153 and 0.908/0.145 for pure WC-Co and WC-Co + Al 2 O 3 coatings, respectively, owing to the anti-reflection effect that the alumina coating provided for improving absorptance and reducing thermal losses.…”