Ceramic matrix composites made of carbon fibres and carbon matrix (C/C) are generally used for aircraft structures and brake discs due to their low density, and good thermal, mechanical, and tribological properties. Silicon carbide (SiC) can be introduced to the matrix to improve the performance of C/C composites, because it increases the hardness and thermal stability, and decreases the chemical reactivity, which leads to the improvement of tribological properties of C/C composites. Thus car...

An effective interionic potential calculation with long range Coulomb, charge transfer interaction, covalency effect, short range overlap repulsion extended, van der Waals interaction, and zero point energy effect is implemented to investigate the pressure dependent structural phase transition (ZnS-type (B3) to NaCl-type (B1) structure), and mechanical, elastic, and thermodynamic properties of silicon carbide (SiC). Both charge transfer interaction and covalency effect are important in reveal...

Electric power generation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic have been examined during cyclic loading with different compressive strain value. A thin PZT ceramic plate attached to a thin brass plate was used. With an increasing compressive strain value in the PZT ceramic plate, the electric voltage increased, and the highest electric voltage was obtained for the sample with the high strain level (0.4%). The electric voltage decreased for the sample with mor...

Plasma synthesized SiC powder obtained from quartz and carbonaceous residue of waste tires was successfully sintered at 1925 ℃ by pressureless liquid-phase method using yttria and alumina as sintering aids (T-SiC). Comparison with sintered SiC obtained from commercial powder (C-SiC) put in evidence of similar sintered density (98%T.D.), but much finer microstructure of T-SiC than that of C-SiC. T-SiC also showed higher flexural strength than C-SiC both at room temperature (508 vs. 458 ...

Alkoxysilane precursors are the most widely used silica source for sol–gel preparation of silicate-based bioactive glass. However, due to their high cost, alternative sources such as bentonite clay are desirable. In the present work, bentonite clay was reacted with sodium hydroxide (NaOH) to extract sodium metasilicate (Na₂SiO₃). The obtained Na₂SiO₃ was converted to gel which was then sintered at 950 ℃ for 3 h to give the bioactive glass in ...

The effect of the partial substitution of Ca²⁺ by Ho³⁺ ions on the electrical and mechanical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi_1.8Pb_0.4)Sr₂Ca_2.1−xHo_xCu_3.1O_10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD)...

An electrochemical method for the synthesis of complex dispersed oxide system Al₂O₃–Fe₂O₃, based on the combined aluminum and iron anodic dissolution in aqueous solution containing chloride ions, has been suggested. The phase composition and morphology of Al₂O₃–Fe₂O₃ dispersed precipitate have been investigated by means of X-ray fluorescence, X-ray diffraction (XRD), and scanning electron microscopy (SEM)....

We show that fully dense nanocrystalline titanate ceramic could be obtained by full crystallization from glass which was prepared by a novel contactless solidification process. Through annealing above glass transition temperature T_g for prescribed duration, BaTi₂O₅ ceramic with grain size of 20–130 nm was successfully fabricated. The dependence of the nanoceramic’s dielectric constant and dissipation on frequency was investigated. The results show clear...

Lithium niobate (LiNbO₃) fibers, obtained from the heat treatment of composite fibers (polymer/inorganic precursors), were successfully prepared by using the blow-spinning technique. A chemical solution containing Li and Nb ions, added to poly(vinyl pyrrolidone) solution, was used as precursor solution. The best condition for producing composite fibers was determined. The morphology of green and crystallized fibers was characterized by scanning electron microscopy (SEM) and reveale...

Superconductor samples of type (CoFe₂O₄)_xGdBa₂Cu₃O_7-δ (0≤x≤0.1) were synthesized by the conventional solid-state reaction technique, whereas nanosized CoFe₂O₄ was prepared by co-precipitation method with grain size of about 8.5 nm. The elemental content of the prepared samples was determined using particle induced X-ray emission (PIXE). The temperature dependence o...