In this study, alumina ceramics containing calcium hexaaluminate are investigated. The specimens obtained by axial pressing of granulated powders and pressureless sintering. Fracture toughness is tested using the indentation method. Microhardness determined Vickers XRD microstructural studies a scanning electron microscope carried out. It was found that use Ca(OH)2 leads to formation CaAl12O19 ...

We consider isentropic gas dynamics equations with unilateral constraint on the density and mass loss. The and pressureless pressure laws are considered. We propose an entropy weak formulation of the system that incorporates the constraint and Lagrange multiplier, for which we prove weak stability and existence of solutions. The nonzero pressure model is approximated by a kinetic BGK relaxation...

Y2O3 ceramics containing up to 4 at.%Zn2+ were prepared by infiltrating a zinc acetate water solution into pre-sintered matrix of Y2O3. After pressureless sintering for 2 h at 1400 °C, ZnO grains dispersed in an identified. The photoluminescence (PL) spectra the Y2O3:ZnO exhibit very broad emission band over entire visible spectral range with intensity maximum about 570−590 nm. PL increases inc...

Single nano high-entropy pyrochlore-type compound (A2B2O7) with 7 different rare-earth cations at site A and 3 metal B equiatomic amounts (7A1/7)2(3B1/3)2O7 is successfully obtained. The powder nominal composition (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 was fabricated by reacting nitrates (site A) chlorides B) glycine during the combustion reaction. XRD analysis revealed that ...

The properties, applications and methods for producing titanium vanadium diborides are considered. These oxygen-free refractory metal-like compounds. As a result, they characterized by high values of thermal electrical conductivity. Their hardness is relatively high. Titanium exhibit significant chemical resistance in aggressive environments. For these reasons, have found application modern tec...