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Si 3 N 4 ceramics, due to their exceptional comprehensive performance, have potential applications in electronic products under the 5th generation mobile communication technology. However, their development is hindered by a lack of color variety and inherent brittleness. To address these issues, we propose the use of an appropriate colorant-sintering additive to enhance densification, promote the growth of β grains and facilitate the formation of a chromogenic phase. This approach aims to simultaneously adjust the color and mechanical properties of Si 3 N 4 ceramics. STEM-EDS results indicate the presence of Re-enriched hollow structures within the Si 3 N 4 matrix. These hollow structures may serve as one of the color centers of silicon nitride. The combined effects of the stress field surrounding the hollow structure, elongated β-Si 3 N 4 grains and intensive dislocations result in strong mechanical properties of Si 3 N 4 ceramics, in which the flexural strength is 852.7 ± 55.8 MPa and the fracture toughness is 11.7 ± 1.0 MPa m1/2. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics have been attractive casing materials for electronics devices under the 5th generation mobile communication technology because of its outstanding comprehensive properties. However, single color cannot meet the needs of most consumers. Here, a typical strategy, involving forming core‐shell structures by utilizing Nd2O3‐MgO‐YAG system, is proposed to rich color. Scanning transmission electron microscope‐energy dispersive X‐ray spectrometry results confirm the presence of core‐shell structures in the silicon nitride matrix, and the core is pore and the shell is Nd‐enriched liquid phase. The Nd‐rich core‐shell structure as the color center makes the silicon nitride appear cyan or blue. [ABSTRACT FROM AUTHOR]

Antiferroelectric (AFE) ceramics are the most promising material system for energy storage in dielectric capacitors due to their fast charging-discharging rate, good chemical stability, and high energy storage density. However, it is exceedingly challenging to simultaneously achieve the excellent recoverable energy density (W re) and high energy storage efficiency (η) at present. In this work, (Pb 0.925-x Sr x La 0.05)(Hf 0.95 Ti 0.05)O 3 AFE ceramics with various Sr contents are fabricated by solid-state sintering processing. It has been found that Sr-doping in the A-site can significantly affect the microstructure, including reducing grain size and modulation period, effectively strengthening the antiferroelectricity, which is responsible for the improved energy storage performance. The high recoverable energy storage density of 10.2 J/cm3 is obtained at 560 kV/cm with an ultra-high efficiency of 93.0% in (Pb 0.875 Sr 0.05 La 0.05)(Hf 0.95 Ti 0.05)O 3 ceramics. These features suggest that Sr-doped PbHfO 3 -based AFE ceramics can serve as promising candidates for capacitor materials, offering significant potential in the realm of energy storage applications. [Display omitted] • Novel PbHfO 3 -based antiferroelectric ceramics with slim P-E loops are prepared. • A W re of 10.2 J/cm3 and a η of 93.0% are achieved in (Pb 0.875 Sr 0.05 La 0.05)(Hf 0.95 Ti 0.05)O 3 ceramic. • Great energy storage from factors like smaller grain size, well elemental distribution and varied modulation structures. [ABSTRACT FROM AUTHOR]

In this paper, silicon nitride (Si3N4) ceramics with black color and high toughness were fabricated by gas pressure sintering and characterized by X‐ray diffraction, Raman, scanning electron microscopy, EDS, and transmission electron microscopy. The in situ formed cobalt silicide was confirmed to contribute to the black color through the introduction of CoO. Due to the addition of CoO, the growth of β‐Si3N4 grains is promoted, forming elongated grains, and eventually forms the self‐reinforcing microstructure. However, with adding excessive CoO, interfacial debonding is found between cobalt silicide and Si3N4 matrix and a decrease in strength was resulted. The optimum composition is 1 mol% CoO in Si3N4, with the fracture toughness of 9.9 ± 0.3 MPa m1/2, flexural strength of 826.1 ± 46.0 MPa, and a much darker black color. The mechanism of color formation is discussed where the black color derives mainly from the metallic silicon and additionally the porosity. [ABSTRACT FROM AUTHOR]

(Pb, La)(Zr, Sn, Ti)O 3 (PLZST) ceramic is one of the most prospective antiferroelectric (AFE) materials for variety of functional applications including energy storage and converter. Systematic structural investigation of domain structures should be of fundamental importance for understanding the structure-property relationship in AFE ceramics. In this study, the hierarchical domain structures and modulated structures correlated to the compositional variation in (Pb 0.97 La 0.02) (Zr 0.50 Sn x Ti 0.50-x)O 3 (x = 0.375, 0.45 and 0.50) were observed and investigated in details by transmission electron microscopy. The PLZST ceramics show exclusively incommensurate modulated structures (IMS) whose modulation period changed from 9.37 to 6.15 and to 4.04 with increasing of the x value. The hierarchical domain structures include, in decreasing scales, AFE domains, incommensurate domains and nanodomains. The elementary domains in PLZST ceramics are pinstriped nanodomains which were formed based on IMS configuration but by frequent modulation of IMS periodicity and formation of faults. Nanodomains accumulated and then dissociated into incommensurate domains and AFE domains successively. The presently revealed structural characteristics in antiferroelectric PLZST may stimulate future researches on the evolution of IMS-based hierarchical domains under external physical fields, e.g. thermal or electrical, and their correlation to the physical performance. [ABSTRACT FROM AUTHOR]

• The composite ceramics Bi 0.5 Na 0.5 TiO 3 -Sm 2 Ti 2 O 7 were successfully prepared. • Excellent electrical properties and stability are obtained in BNT-STO ceramics. • A new effective method to design high ESP ceramic materials is proposed. The comprehensive performance of ferroelectric ceramic materials is a significant factor limiting the practical application. In this work, a novel strategy of constructing diphase compounds is proposed to significantly enhance the energy storage properties of Bi 0.5 Na 0.5 TiO 3 -based ceramics. A composite ceramic of pyrochlore phase Sm 2 Ti 2 O 7 modified perovskite phase Bi 0.5 Na 0.5 TiO 3 is successfully prepared and systematically studied. As the concentration of Sm 2 Ti 2 O 7 increases, the dielectric breakdown strength is greatly strengthened because of expanded band gap and shrunk grain size, and the relaxor behavior is enhanced due to the effect of linear character pyrochlore. As a result, the optimized composition demonstrates excellent energy storage properties including high recoverable energy storage density (W rec) of 6.387 J/cm3 at 402 kV/cm, superior stability of temperature (<6% variation in − 120 ∼ 120 °C), frequency (∼4% variation in 5 ∼ 500 Hz) and cycling (∼2% variation within 106 cycles). Besides, fast discharge behavior of t 0.9 ∼ 29.4 ns and high power density of 80.49 MW/cm3 at 200 kV/cm are also achieved. This study presents a novel strategy to enhance the performance of BNT-based materials through forming composite ceramic, which is anticipated to be a general method for other material systems as regards the design of advanced energy storage ceramics. [ABSTRACT FROM AUTHOR]