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To date, the application of additive manufacturing techniques in fabricating SiAlON ceramics with intricate geometries has been limited. This investigation demonstrates the synthesis of SiAlON ceramics by integrating silicon nitride (Si 3 N 4) powders with variable proportions of aluminum nitride (AlN) utilizing the vat photopolymerization (VPP) approach. The effects of AlN content on the properties of SiAlON ceramic slurries, green bodies, and sintered parts were systematically investigated. Notably, the slurry's viscosity decreases progressively with an increase in AlN, aligning with VPP printing prerequisites. Additionally, the curing depth of the slurry enhanced proportionally with AlN augmentation, elevating from 21 μm to 44 μm at an energy exposure of 800 mJ/cm2, with the pivotal addition being 15 vol% AlN, where optimal properties were achieved. The zeniths of flexural strength, bulk density, relative density, and thermal conductivity were recorded at 385.66 ± 22.63 MPa, 3.34 ± 0.09 g/cm3, 96.22 ± 2.55 %, and 37.4 ± 0.31 W m−1 K−1, respectively. The fabrication of SiAlON ceramics with complex configurations was successfully realized, heralding a novel methodology for future SiAlON ceramic production. [ABSTRACT FROM AUTHOR]

Ta-doped Bi 3.25 La 0.75 Ti 3 O 12 (BLTT)/ZnO films were fabricated on Pt(111)/Ti/SiO 2 /Si substrates by a magnetron sputtering method. Firstly, ZnO crystal thin films were grown on the substrates by a reactive sputtering method. Then, BLTT thin films were deposited on the ZnO layers at room temperature and post-annealed at 600 °C. The micromorphology, ferroelectric and dielectric properties of BLTT/ZnO films were analyzed. The XRD analysis shows that ZnO buffer layer significantly reduces the crystallization temperature of BLTT thin film. The TEM results show that lamellar BLTT grains are grown on ZnO layer at a certain angle with few elements diffusion at the interface of ZnO phase and Bi 4 Ti 3 O 12 phase. The ferroelectric properties indicate that BLTT/ZnO films exhibit different remanent polarization and coercive fields under electric field with different directions. The novel mechanism of tailoring ferroelectric properties may open new possibilities for designing special ferroelectric devices. [ABSTRACT FROM AUTHOR]

Electromagnetic wave (EMW) absorbing materials have excellent potential for various applications in civil engineering and the military. In this study, siliconboron carbonitride (SiBCN) ceramics with excellent EMW absorption capability and oxidation resistance were obtained by adjusting the boron content. The results revealed that the graphite crystallite size in the SiBCN ceramics increased from 3.42 to 3.78 nm, whereas the thickness of the oxide layer decreased from 16.6 to 8.2 μm. The highest electrical conductivity and permittivity for the SiBCN ceramics were obtained when the boron content was 5%. The minimum reflection loss was −35.25 dB at 10.57 GHz and a ceramic thickness of 2.0 mm. At a temperature of 600 °C, the SiBCN ceramic exhibited excellent EMW attenuation ability; particularly, the minimum reflection loss reached −29.18 dB at 9.65 GHz and a ceramic thickness of 2.5 mm. The superior EMW absorption properties of the SiBCN ceramics at high temperatures can be ascribed to the synergistic effect of relaxation and conductivity. The results suggest that boron could enhance the transformation of amorphous carbon into crystalline graphite and increase the number of heterointerfaces and conductive paths. This work provides a method for obtaining SiBCN ceramics with excellent EMW absorption properties. Therefore, the electrical conductivities of the ceramics increased with increasing temperature as both the migration and hopping conductances increased with increasing temperature. Additionally, the increase in temperature enabled the electrons to leap from the valence band into the conduction band, which also improved the electrical conductivity. [ABSTRACT FROM AUTHOR]

A one-step hydrothermal treatment was used to deposit a nano silver-loaded magnesium-aluminum hydrotalcite (Ag/Mg-Al) layered double hydroxide (LDH) coating onto the surface of a Mg-Zn-Ca alloy to improve the corrosion resistance and antibacterial properties of magnesium alloys for biomedical applications. The effect of experimental parameters such as temperature and time on the microstructure, compositions, and corrosion resistance of the Ag/LDH coating during the hydrothermal treatment was investigated to optimize the preparation process. Additionally, the in vitro degradation performance, antibacterial performance and biocompatibility of the coating were evaluated to determine the optimal preparation condition. The results show that when the LDH–NO 3 – coating is prepared at 110 °C for 10 h, the constituting silver particles (dimensions, 10–30 nm) are obtained, while the corrosion current density and the corrosion rate decrease to 4.41 μA/cm2 and 0.27 mm/year, respectively. The antibacterial experiment demonstrates that the coating effectively inhibits the reproduction of Escherichia coli while offering remarkable biocompatibility. [ABSTRACT FROM AUTHOR]

In this study, Ti–Si–C composite coatings were synthesized via plasma spraying of agglomerated powders prepared by a spray drying/precursor pyrolysis technology using Ti, Si, and sucrose powders. The influence of Si content, ranging from 0 wt% to 24 wt%, on the microstructure, mechanical properties, and oxidation resistance of the composite coatings was investigated. Results show that the phase composition of the Ti–Si–C composite coatings changes with the increasing Si content. The coatings without Si addition consist of TiC and Ti 3 O; the coatings with 6–18 wt% Si are composed of TiC, Ti 5 Si 3 , and Ti 3 O; the coatings with Si content of 24 wt% form only TiC and Ti 5 Si 3 phases. As the Si content increases, the hardness of the Ti–Si–C composite coatings increases first and then decreases, depending on the intrinsic hardness of the ceramic phases, the brittleness of Ti 5 Si 3 , and the defects such as pores and cracks. The Ti–Si–C composite coatings have high wear resistance due to the in-situ synthesized high-hardness TiC and Ti 5 Si 3. Owing to the high brittleness of Ti 5 Si 3 , the increasing Si content leads to higher wear volume loss at room temperature, which can be partially improved in high-temperature wear tests. The oxidation resistance of Ti–Si–C composite coatings increases with the increase of Si content, and the higher the oxidation temperature, the more obvious the influence of the Si addition on oxidation resistance. [ABSTRACT FROM AUTHOR]

Yttria-stabilized zirconia coatings were prepared by atmospheric plasma spraying, and the bonding strength of the coatings was determined by tensile testing. The microstructure of the coating, including grains and pores, was characterized using scanning electron microscopy and electron backscatter diffraction. The results show that the higher the proportion of columnar grains, the higher the bonding strength. The large misorientation at the small grains leads to large stress, which is easy to fracture in the tensile process, so the existence of small grains leads to poor bonding strength. By using image processing, pores were classified as holes, cracks, and microcracks, and their proportions were calculated. It was found that both holes and transverse and vertical cracks in pores linearly affected the bonding strength; the influence of holes was the greatest, and the influence of microcracks was the smallest. In conclusion, the smaller the porosity, the greater the bonding strength of the coating. [ABSTRACT FROM AUTHOR]

Dense SiC-(Ti x Zr 1–x)B 2 composite ceramics were prepared via solid-state spark plasma sintering (SPS) by controlling the proportion of ZrB 2 (in the range of 5–25 vol%). Through data fitting, a linear functional relationship was established between x and 2θ for the (Ti x Zr 1–x)B 2 solid solution, which rendered it amenable to characterization analysis. The results show that the 2-D morphology of (Ti x Zr 1–x)B 2 tended to transform from angular to round as the ZrB 2 proportion was increased, which was beneficial in crack deflection and increasing the fracture toughness. Moreover, the growth of SiC grains around the solid solution was inhibited, which improved its mechanical properties. The composite ceramic containing 15 vol% of ZrB 2 had the best mechanical properties, with its Vickers hardness, bending strength and fracture toughness reaching 26.12 GPa, 499 MPa, and 6.45 MPa•m1/2, respectively. [ABSTRACT FROM AUTHOR]

Ytrria-stabilized zirconia (YSZ) thermal barrier coatings were prepared via atmospheric plasma spraying, and its thermal shock performance was evaluated. Residual stress was analyzed qualitatively and quantitatively via electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). And image analysis and scanning electron microscopy were used to quantitatively analyze the length, direction, and proportion of the cracks in the coating. A relationship was established between the microstructure of the coating and its thermal shock performance. The results demonstrated that the spraying power altered the microstructure of the coating. The microstructure and residual stresses affected the thermal shock performance of the coating. This may be due to an increase in the spraying power, which led to a decrease in the grain size and service life of the coating. [ABSTRACT FROM AUTHOR]