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Titanium carbide ceramic is a good potential material used in high temperature environment for its good strength, erosion resistance and thermal stability. Unfortunately, the low thermal shock resistance and low fracture toughness are the well-known impediments to its application as high temperature structure components. In order to extend the application of TiC ceramics at high temperature, 20 vol.% short carbon fiber was added into TiC matrix to improve the thermomechanical properties. With the incorporation of carbon fiber, the thermal expansion coefficient of TiC composites was decreased and the thermal conductivity was increased slightly below 900 °C. The flexural strength was improved from 471 MPa for monolithic TiC to 593 MPa for TiC composites, and the strengthening effect of carbon fiber became more prominent at high temperatures. The addition of fiber decreased the elastic modulus of TiC composite. The elastic modulus of the composite decreased with increasing temperature. The improvement of high temperature strength and thermal conductivity and the decrease of thermal expansion will benefit the application of TiC composites in high temperature environment where the temperature usually varies. [Copyright &y& Elsevier]

Abstract: A series of zirconate compounds with the general formula Sm2– x La x Zr2O7 (0⩽ x ⩽1.0) were prepared by pressureless-sintering method at 1973K for 10h in air. The relative density, structure and electrical conductivity of Sm2– x La x Zr2O7 ceramics were investigated by the Archimedes method, X-ray diffraction and impedance spectroscopy measurements. Sm2– x La x Zr2O7 (0⩽ x ⩽1.0) ceramics exhibit a pyrochlore-type structure. The measured electrical conductivity of Sm2– x La x Zr2O7 ceramics obeys the Arrhenius relation and gradually increases with increasing temperature from 673 to 1173K. Sm2– x La x Zr2O7 ceramics are oxide-ion conductors in the oxygen partial pressure range of 1.0×10−4 to 1.0atm at all test temperature levels. The electrical conductivity of Sm2– x La x Zr2O7 ceramics decreases with increasing lanthanum content at identical temperature levels. [Copyright &y& Elsevier]

Abstract: The phase stability and thermal expansion property of ZrO2–NdO1.5–AlO1.5 ceramics from 50 to 1550°C were investigated for potential high-temperature structural and functional applications. All ZrO2–NdO1.5–AlO1.5 ceramics consist mainly of perovskite-like NdAlO3 and pyrochlore or fluorite (F–ZrO2) structures, and have relatively stable thermal expansion coefficients from 200 to 1400°C. However, ZrO2–NdO1.5 (Nd2Zr2O7) ceramics have a single pyrochlore-type lattice, and exhibit a distinct decreasing tendency of thermal expansion coefficients from 400 to 1550°C. The thermal expansion coefficients of ZrO2–NdO1.5–AlO1.5 ceramics are within the range of 10.3–11.5×10−6 K−1 at 1400°C, which are of the same order of magnitude as 7wt.% yttria stabilized zirconia. [Copyright &y& Elsevier]

A convenient direct ink writing porous ceramic preparation strategy incorporating green body strengthening measure was provided. Different hydrogen bond interactions between particles in polar and nonpolar solvents have been successfully applied to regulate the rheological properties of 3D printing ink. Inks with different (NH 4)H 2 PO 4 content were systematically optimized, which exhibited acceptable ambient stability and superior printing behavior. The phosphoric acid generated by decomposition of (NH 4)H 2 PO 4 reacts with silica or oxide layer of silicon nitride to form Si–O–P binder by a pretreatment at low temperature to strengthen the green body. The compressive strength of green body fabricated by ink with 0.2 g/mL (NH 4)H 2 PO 4 was increased by 415%. The Si 2 N 2 O single wall frame structure parts with a compressive strength of 3.33 ± 0.14 MPa under a frame density of 1.14 ± 0.05 g/cm3 were fabricated. The dielectric constants of the developed ceramic parts range from 3.57 to 4.21. A systematic study of design and preparation of ink and quantization of molding parameters provide a reference for in-situ reinforced the ceramic green body of silica, silicon nitride and their composites, as well as fabrication of their corresponding highly porous ceramic components based on the direct ink writing. Image 1 • A strategy for direct ink writing of high-strength Si 2 N 2 O green bodies as well as their ceramic components was provided. • The rheological properties of inks were regulated by the different hydrogen bond interactions between particles in C 10 H 22 O 5 and H 2 O. • The phosphorus elements introduced by (NH 4)H 2 PO 4 aqueous solution were evenly distributed in green body and ceramic part. • The compressive strength of Si 2 N 2 O green body was increased up to 415% due to the strengthening of Si–O–P binder. [ABSTRACT FROM AUTHOR]