A series of (Ba 0.2 Sr 0.2 Na 0.2 Ca 0.2 La 0.2 )(Zr x Ti 1- x )O 3 (BSNCLZ x T 1- x ) ( x = 0, 0.05, 0.1, 0.15, and 0.2) high-entropy ceramics were prepared in forms of bulks and thin films by conventional sintering and spin-coating, respectively. All ceramic bulks and thin films are composed of a single perovskite-structured solid solution. The introduction of the Zr element reduces the dielectric loss of bulks and thin films and improves the frequency stability of the dielectric constant. The ceramic bulks have a higher dielectric constant and lower loss than their corresponding thin films. As x rises from 0 to 0.2, the breakdown strength E b of the ceramic bulks increases from 209 to 327 kV/cm, and that of thin films enhances from 890 to 1770 kV/cm. The bulks and thin films of BSNCLZ 0.1 T 0.9 possess the maximum recoverable energy density W rec (0.82 and 3.48 J/cm 3 ) and energy storage efficiency η (95.8% and 86.8%).
Zili Liu,Chong Wei,Yueying De,Songbin Zhang,Cheng Zhang,Xiaoqiang Li
High-entropy pyrochlore ceramics have received significant attention in the field of nuclear materials due to their ability to immobilize radioactive waste . In this study, a range of medium and high-entropy Ti-based pyrochlore powders were synthesized by a two-step method. Interestingly, a monoclinic phase was observed in some powders. An innovative experiment was conducted to adjust the cation ratio at the A site, which revealed that certain cations with larger ionic radii exhibit low solid solubility in the pyrochlore lattice, resulting in the formation of the monoclinic structure. To avoid the formation of monoclinic phase, the crystal structure was adjusted by introducing Zr 4+ at the B site. Based on the selection of single-phase powders, high-density pyrochlore ceramic bulks with uniform distribution of elements were prepared by spark plasma sintering . Here (Sm 1/5 Yb 1/5 Gd 1/5 Er 1/5 Dy 1/5 ) 2 Ti 2 O 7 bulks exhibited the smallest grain size at approximately 2.48 µm among all sintered samples and demonstrated a hardness of around 10.14 GPa.
Zirconium containing phenyl silicone resin were synthesized through hydrolysis among zirconium n-propoxide (ZP), diphenyldimethoxysilane, and 3-(trimethoxysily)propyl methacrylate under acidic conditions. The results indicated that the resins have favorable thermal stability for practical usage, and the thermal weightless of all resins are less than 3% under 200°C.The refractive index of the materials is positively correlated with zirconium content, and tunable between 1.57 and 1.59, and light transmittance does not change significantly with the increase of zirconium element. In addition, the resins can be stably stored for more than 6 months without any effect on the application.
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