Bulk samples of lanthanum polyphosphate were synthesized through a hydrothermal hot-pressing (HHP) process. In this process, pressing temperature, pressure and volume of water were varied in order to improve the density and strength of the resulting materials. The strength of the bulk samples was estimated through drilling and ultrasonic treatments. In order to improve the strength of the materials, the use of microwave irradiation was examined. Lanthanum polyphosphate formed porous bulk samp...

The electrocaloric (EC) effect accompanied with the ferroelectric to paraelectric phase transition in (111)-oriented PbMg_1/3Nb_2/3O₃ (PMN) is investigated. It is shown that the largest change ΔT is 0.37 K in 3 kV/cm electric field shift near the Curie temperature of 221 K; th...

This paper investigated the corrosion behaviors of Ti₃AlC₂ at 700 ℃ in molten KOH with various mass ratios. If the mass ratio of KOH:Ti₃AlC₂≤2, Ti₃AlC₂ can resist KOH hot corrosion in 2 h. Ti₃AlC₂ suffered serious corrosion attack if the mass ratio≥3. The main compositions of corroded samples were amorphous graphite and potassium titanates (K₂O·nTiO₂). If t...

This work focused on the fabrication of silicon oxycarbide ceramic (SiOC) foams as well as dense compacts using poly(hydridomethylsiloxane) (PHMS) as a polymer precursor. The room-temperature cross-linking of PHMS was achieved by the addition of 1,4-diazabicyclo [2.2.2] octane (DABCO) with the release of hydrogen gas as a by-product. This resulted in self-blowing of the polymer precursor at room temperature and thereby offered the possibility of producing SiOC foams without the need of any ex...

Polyorganoborosilazane ((B[C₂H₄–Si(CH₃)NH]₃)_n) was synthesized via monomer route from a single-source precursor and thermolyzed at 1300 ℃ in argon atmosphere. The as-thermolyzed Si–B–C–N ceramic was characterized using X-ray diffraction (XRD) and Raman spectroscopy. The crystallization behavior of silicon carbide in the as-thermolyzed amorphous Si–B–C–N matrix was understood by XRD studies, and the crystallite size calculate...

Yttria-stabilized zirconia (YSZ) thin nanocrystalline coatings at different substrate preheating temperatures were deposited via electron beam-physical vapour deposition (EB-PVD). Nanocrystalline ZrO₂–Y₂O₃ was deposited on the bond coat in order to compensate for the coefficient of thermal expansion (CTE), which can be functionalized as a thermal barrier coating (TBC). The aim of this study was to evaluate mechanical properties with respect to adhesion of zirc...

Sol–gel processed alumina (Al₂O₃) thin film has been investigated for sensing moisture. The sensor was based on ordered nanoporous Al₂O₃ thin film, which consisted of gold electrodes on both sides of the film forming parallel plate capacitor. Alumina substrate was used for supporting thin film moisture sensor. Hydrophilicity was achieved by controlling the surface energy of the substrate and polymer (polyvinyl alcohol (PVA)) optimization was done fo...

Single phase of SrIrO₃ powders and ceramics were obtained by solid-state chemical reaction method and spark plasma sintering (SPS) technique, respectively. Phase evolutions, characteristics, morphology and resistivity of the samples were studied by using thermogravimetric analysis–differential scanning calorimetry (TG–DSC), X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM) and four-point probe method, respectively. The results showed that the reaction ...

Lead-free (K_0.4425Na_0.52Li_0.0375)(Nb_0.8825Sb_0.07Ta_0.0475)O₃ (KNLNST) piezoelectric ceramics are synthesized by the conventional solid-state reaction method. The sintering temperature and poling temperature dependence of ceramic properties are investigated. Previous studies have shown that variation of sintering temperature can cause phase transition, similar to the morphotropic phase boundary (MPB) behavior induced b...

Solid-state ceramic technique route is used for synthesizing Cr-doped haematite α-Fe_2-xCr_xO₃ (x = 0, 0.125, 0.50 and 1) samples. Single phase and corundum (Al₂O₃) type structure is revealed from the X-ray diffraction (XRD) patterns. The Raman spectra of α-Fe_2-xCr_xO₃ illustrate seven phonon modes. On substitution of Cr (x = 0, 0.125, 0.50...

An unconventional method for determining the fracture resistance of brittle materials is discussed. This method employs a conical indenter to chip the rectangular edge of the specimen. Particular features of the method are the use of small specimens and the evaluation of the resistance of materials to the nucleation, initiation and propagation of a crack. It is shown that this method is somewhat similar to the Hertzian fracture method and to the way that early man selected stones to make tool...

The CaO–P₂O₅–SiO₂–MgO system presents several compounds used as biomaterials such as hydroxyapatite (HA), tricalcium phosphate (TCP) and TCP with magnesium substituting partial calcium (TCMP). The β-TCMP phase with whitlockite structure has interesting biological features and mechanical properties, meeting the requirements of a bioactive material for bone restoration. In this work, the production of Mg-doped TCP, β-TCMP, has been investigated by ...