@article{Chen2023, 
author = {Lin Chen and Keren Luo and Baihui Li and Mingyu Hu and Jing Feng},
title = {Mechanical property enhancements and amorphous thermal transports of ordered weberite-type RE3Nb/TaO7 high-entropy oxides},
year = {2023},
journal = {Journal of Advanced Ceramics},
volume = {12},
number = {2},
pages = {399-413},
keywords = {high-entropy oxides (HEOs), RE niobates/tantalates (RE3Nb/TaO7), stiffness (K), fracture toughness (KIC), thermal transports},
url = {https://www.sciopen.com/article/10.26599/JAC.2023.9220693},
doi = {10.26599/JAC.2023.9220693},
abstract = {A3BO7-type (A = rare earth (RE), B = Nb or Ta) oxides have been studied as protective coating materials because of their low thermal conductivity; however, their hardness, toughness, and stiffness are insufficient, particularly for members with webeirte-type structures. In this work, we have synthesized two high-entropy oxides (HEOs) of weberite-type RE niobates/tantalates (RE3Nb/TaO7), i.e., (Nd1/7Sm1/7Eu1/7Gd1/7Dy1/7Ho1/7Er1/7)3NbO7 (7HEOs-Nb) and (Nd1/7Sm1/7Eu1/7Gd1/7Dy1/7Ho1/7Er1/7)3(Nb1/2Ta1/2)O7 (7HEOs-NbTa), to overcome the mechanical deficiencies. The short- and long-range ordered arrangements of RE cations in the A-site and Nb/Ta cations in the B-site were identified by the X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive spectrometry (EDS), and transmission electron microscopy. The enhancements in hardness (H = 9.4 GPa) and fracture toughness (KIC = 2.0 MPa·m1/2) were realized by grain refinement, solid solution strengthening, and high stiffness (K). The exceptional phase stability at 25−1500 ℃, amorphous thermal conductivity (k = 1.5−1.7 W·m−1·K−1 at 25−900 ℃), and high thermal expansion coefficients (TEC > 11.0×10−6 K−1 at 1500 ℃) further supported their potential application as protective coating materials.}
}