Scalable and Ultrathin High‐Temperature Solar Selective Absorbing Coatings based on the High‐Entropy Nanoceramic AlCrWTaNbTiN with High Photothermal Conversion Efficiency

Solar RRL ◽  
2021 ◽  
Author(s):  
Cheng-Yu He ◽  
Xiang-Hu Gao ◽  
Xiao-Li Qiu ◽  
Dong-Mei Yu ◽  
Hui-Xia Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Conversion Efficiency ◽  
Photothermal Conversion ◽  
High Entropy

scholarly journals Fabrication and Characterization of Quinary High Entropy-Ultra-High Temperature Diborides

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 108-120
Author(s):  
Simone Barbarossa ◽  
Roberto Orrù ◽  
Valeria Cannillo ◽  
Antonio Iacomini ◽  
Sebastiano Garroni ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Phase ◽  
Nominal Composition ◽  
High Entropy ◽  
Chemical Complexity ◽  
Alternative Processing ◽  
Plasma Sintering ◽  
High Temperature Synthesis ◽  
Spark Plasma

Due to their inherent chemical complexity and their refractory nature, the obtainment of highly dense and single-phase high entropy (HE) diborides represents a very hard target to achieve. In this framework, homogeneous (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2, and (Hf0.2Zr0.2Nb0.2Mo0.2Ti0.2)B2 ceramics with high relative densities (97.4, 96.5, and 98.2%, respectively) were successfully produced by spark plasma sintering (SPS) using powders prepared by self-propagating high-temperature synthesis (SHS). Although the latter technique did not lead to the complete conversion of initial precursors into the prescribed HE phases, such a goal was fully reached after SPS (1950 °C/20 min/20 MPa). The three HE products showed similar and, in some cases, even better mechanical properties compared to ceramics with the same nominal composition attained using alternative processing methods. Superior Vickers hardness and elastic modulus values were found for the (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2 and the (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 systems, i.e., 28.1 GPa/538.5 GPa and 28.08 GPa/498.1 GPa, respectively, in spite of the correspondingly higher residual porosities (1.2 and 2.2 vol.%, respectively). In contrast, the third ceramic, not containing tantalum, displayed lower values of these two properties (25.1 GPa/404.5 GPa). However, the corresponding fracture toughness (8.84 MPa m1/2) was relatively higher. This fact can be likely ascribed to the smaller residual porosity (0.3 vol.%) of the sintered material.

Single-phase (Hf-Mo-Nb-Ta-Ti)C high-entropy ceramic: A potential high temperature anti-wear material

2021 ◽  
Vol 157 ◽  
pp. 106883
Author(s):  
Qichun Sun ◽  
Hui Tan ◽  
Shengyu Zhu ◽  
Zongxiao Zhu ◽  
Long Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Phase ◽  
High Entropy

The role of Si on microstructure and high-temperature oxidation of CoCr2FeNb0.5Ni high-entropy alloys coating

2021 ◽  
pp. 109417
Author(s):  
Minyu Ma ◽  
Aihua Han ◽  
Zunjun Zhang ◽  
Yong Lian ◽  
Chao Zhao ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
High Entropy Alloys ◽  
Temperature Oxidation ◽  
High Entropy
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