In this paper, we present a comprehensive study of the aluminum oxynitride doped with zirconium ions in terms of physical, mechanical and optical properties. The Zr content was varied in a wide range of 0.01-5.0 at. %, Zr ions were introduced in a form of zirconia ZrO2 into Al2O3-AlN mixtures, which were sintered for 2 h at 1750 degrees C in a flow of nitrogen to get gamma-AlON Zr-doped samples. Zirconia was found to be an effective sintering aid for synthesis of gamma-AlON providing formation of single-phase gamma-AlON at Zr content of 0.05 at. %. The solubility limit for Zr ions in the AlON matrix was determined as 0.1 at. %. According to XPS study, the most probable state of Zr in the AlON matrix is Zr4+, while the impurity phases contain Zr3+. Vickers hardness, fracture toughness KIc and bending strength shows no dependence on the Zr content below 0.5 at. % and then slowly increases by 3-10 % with an increase of Zr content from 1.0 at. % to 5.0 at. %. PCL spectra are caused by intrinsic and impurity defects of the AlON matrix; the total intensity decreases with an increase of Zr content. The Eg is found to range from 5.72 to 5.77 eV depending on the Zr content.

The article discusses the possibilities of preparing high-quality powder materials from heat-resistant light alloys based on refractory monoaluminides of nickel β-NiAl and ruthenium β-RuAl for the manufacture of compact samples/products of complex shape using additive technologies with minimal final machining. Additive technologies are based on the use of spherical precursor micro-powders with a regulated granulometric composition, good fluidity and an oxide-free surface. The possibilities of obtaining precursors from RuAl-based alloys by plasma spheroidization of powders obtained by crushing mixtures from scrap samples of alloys based on RuAl with various additives are considered.

The article presents a comprehensive study of the synthesis, phase formation, electronic structure, and optical properties of cobalt-doped aluminum oxynitride Al5O6N (AlON) in the concentration range of 0.01-5 at%. The solubility limit of cobalt in AlON is found to be 0.1-0.2 at% compared to Al. No corundum is detected even at the lowest cobalt content (0.01 at%), but a low amount of AlN and Co or Co4N is observed. Cobalt ions are incorporated into AlON with the typical oxidation state of Co2+ and form Co-O and Co-N bonds in a ratio of 92/8. The bandgap (Eg) and lattice parameters of AlON:Co are found to be in the range of 5.72-5.84 eV and 7.9411-7.9539 & Aring;, respectively, and are influenced by the oxygen content. Pulsed cathodoluminescence spectra show five emission bands, with some attributed to (VAl-ON)-type defects. The luminescence intensity of AlON:Co decreases with higher contents of cobalt ions.

The structure of hydroxyapatite (HA) plasma coatings obtained by changing the power of the plasma torch (P) from 20 to 26 kW was studied by X-ray diffraction analysis. All coatings contained the decomposition products of hydroxyapatite in the plasma flow, phases of tetracalcium phosphate (TTCP) and CaO. Their number, which increases with increasing P and plasma temperature (Tp), is determined by the partial loss of phosphorus by the initial HA powder in plasma and the shift in the chemical composition of the coating to higher calcium contents. An increase in P and Tp is accompanied by an increase in the intensity of the HA basic texture. In the range of 24 < P < 26 kW, the intensity ratio of X-ray reflections HA δ = I(200)/I(211) exceeds 3.0 in its value, while at P = 20 kW δ <1.5. The presence of orientation relationships between the predominant crystallographic orientations of HA and TTCP crystals in coatings is associated with the similarity of their structures, the proximity of lattice periods, and the presence of identical fragments in their structures. The possibility of the formation of mixed-layer structures involving these compounds is discussed. The following factors are considered as the factors that have the greatest influence on the nature of the dependences obtained: the substrate temperature, the particle size in the initial HA powder, and the composition of the plasma gases.

Abstract An X-ray diffraction study of ceramic samples of the BiScO3–PbTiO3–PbMg⅓Nb⅔O3 system with compositions close to the morphotropic phase boundary was carried out at room temperature. The existence of wide areas of solid solutions has been established. The symmetry of the PbTiO3-based solid solutions is tetragonal (space group P4mm). The symmetry of the PbMg⅓Nb⅔O3-based solid solutions is cubic (space group Pm3‾m). Near the BiScO3 side, the solid solutions are rhombohedral (space group R3m). During the morphotropic phase transition from the cubic solid solutions to the tetragonal ones, additional phases appear. If a tetragonal phase prevails ((1 − 2x)BiScO3–xPbTiO3–xPbMg⅓Nb⅔O3 x = 0.46; (1 − 2x)BiScO3–1.1xPbTiO3–0.9xPbMg⅓Nb⅔O3 x = 0.45 and 0.42), a satisfactory model is a model with a minority cubic phase (space group Pm3‾m). If a cubic phase prevails ((1 − 2x)BiScO3–1.1xPbTiO3–0.9xPbMg⅓Nb⅔O3 x = 0.39 and 0.36; (1 − 2x)BiScO3–0.8xPbTiO3–1.2xPbMg⅓Nb⅔O3 x = 0.4), a model with a minority monoclinic phase (space group Cm) or with two minority phases: tetragonal (space group P4mm) and monoclinic (space group Cm) is satisfactory.

The paper considers the effect of hydrothermal treatment, simulating a long stay in a biological environment, on the phase composition and bending strength of Al2O3 – [ZrYb]O2 composites containing a variable amount of Al2O3 and including strontium hexaaluminate. It has been shown that composites retain bending strength after hydrothermal action. This fact indicates the preservation of the phase composition in the volume of materials. It is determined that a monoclinic phase of zirconia is formed in the near-surface layer of the samples, the amount of which ranges from 11 to 9 %, correlating with the increase in the content of alumina in the composite. The formation of the monoclinic phase of zirconia in such an amount is well below the limit of 25 % specified in ISO 13356 2015 Implants for surgery — Ceramic materials based on yttria-stabilized tetragonal zirconia (Y-TZP). The results obtained make it possible to recommend Al2O3 – [ZrYb]O2 composites containing strontium hexaaluminate for medical applications.

An X-ray diffraction study of ceramic samples of the BiScO3-PbTiO3-PbMg1/3Nb2/3O3 system with compositions close to the morphotropic phase boundary was carried out at room temperature. The existence of wide areas of solid solutions has been established. The symmetry of the PbTiO3-based solid solutions is tetragonal (space group P4mm). The symmetry of the PbMg1/3Nb2/3O3-based solid solutions is cubic (space group Pm (3) over barm). Near the BiScO3 side, the solid solutions are rhombohedral (space group R3m). During the morphotropic phase transition from the cubic solid solutions to the tetragonal ones, additional phases appear. If a tetragonal phase prevails ((1 - 2x)BiScO3-xPbTiO(3)-xPbMg(1/3)Nb(2/3)O(3) x = 0.46; (1 - 2x)BiScO3-1.1xPbTiO(3)-0.9xPbMg(1/3)Nb(2/3)O(3) x = 0.45 and 0.42), a satisfactory model is a model with a minority cubic phase (space group Pm (3) over barm). If a cubic phase prevails ((1 - 2x)BiScO3-1.1xPbTiO(3)-0.9xPbMg(1/3)Nb(2/3)O(3) x = 0.39 and 0.36; (1 - 2x)BiScO3-0.8xPbTiO(3)-1.2xPbMg(1/3)Nb(2/3)O(3) x = 0.4), a model with a minority monoclinic phase (space group Cm) or with two minority phases: tetragonal (space group P4mm) and monoclinic (space group Cm) is satisfactory.

Ceramic samples with compositions along the (1 – 2 x )BiScO 3 ·(2 – y ) x PbTiO 3 ∙ yx PbMg 1/3 Nb 2/3 O 3 ( y = 1.2, 1.0, 0.9, 0.5) sections in the BiScO 3 –PbTiO 3 –PbMg 1/3 Nb 2/3 O 3 (BS–PT–PMN) system have been characterized by X-ray diffraction and dielectric, piezoelectric, and thermally stimulated depolarization current measurements. The materials with 1 – x ≲ 0.5 have been shown to consist of perovskite solid solutions. With increasing BS content, the symmetry of the solid solutions rises from tetragonal to cubic. In the intermediate composition region (morphotropic region (MR)), the samples consist of a mixture of solid solutions differing in symmetry. We have located the MR boundaries and examined the effect of composition on the dielectric and piezoelectric properties of the solid solutions.

Методом осаждения из растворов получены наноразмерные порошки церийсодержащих трикальцийфосфатов (ТКФ, Ca 3 (PO 4 ) 2 ) со структурой витлокита. Содержание церия в материалах после термической обработки при 1300°C составило 0, 0.07, 0.18 и 0.39 мас. %, что соответствует значениям х = 0, 0.0025, 0.006, 0.013 для общей формулы Ca 3 – х Ce 2 х /3 (PO 4 ) 2 . С повышением содержания церия увеличивается термическая стабильность β-модификации ТКФ. Полученные церийсодержащие порошки ТКФ обладают люминесцентными свойствами при облучении источником света длиной волны 270–320 нм с максимумом при 360–390 нм, характерным для эмиссии Се 3+ . В зависимости от концентрации церия и температуры обработки материалов происходит смещение спектров свечения.

Abstract The xBa(Ti(1−y)Zry)O3–(1−x)PbTiO3 ceramic samples with x = 0.3, y = 0.95; x = 0.3, y = 0.7; x = 0.3, y = 0.3; x = 0.3, y = 0.05; x = 0.5, y = 0.05 were synthesized by a solid state reaction technique. The XRD patterns of these samples have anisotropic broadening of diffraction peaks. The crystallographic data were analyzed by the Rietveld method. During the refinement process the Stephens’s approach was used. All the samples studied are solid solutions with the tetragonal perovskite structure. The degree of tetragonal distortion of these solid solutions decreases with an increase in the Zr content. The microstructure analysis showed that the broadening of the diffraction peaks on the XRD patterns is due to both strains and small crystallite sizes.

Ceramic samples with compositions along the (1 – 2x)BiScO3·(2 – y)xPbTiO3∙yxPbMg1/3Nb2/3O3 (y = 1.2, 1.0, 0.9, 0.5) sections in the BiScO3–PbTiO3–PbMg1/3Nb2/3O3 (BS–PT–PMN) system have been characterized by X-ray diffraction and dielectric, piezoelectric, and thermally stimulated depolarization current measurements. The materials with 1 – x ≲ 0.5 have been shown to consist of perovskite solid solutions. With increasing BS content, the symmetry of the solid solutions rises from tetragonal to cubic. In the intermediate composition region (morphotropic region (MR)), the samples consist of a mixture of solid solutions differing in symmetry. We have located the MR boundaries and examined the effect of composition on the dielectric and piezoelectric properties of the solid solutions.

Cerium-containing tricalcium phosphate (TCP, Ca3(PO4)2) nanopowders with the whitlockite structure have been prepared via precipitation from solution. After heat treatment at 1300°C, the materials contained 0, 0.07, 0.18, and 0.39 wt

We have studied the effect of sodium fluoride as a sintering aid for β-sialons on the phase composition and physicomechanical properties of Si5AlON7 and Si4Al2O2N6. Two-step high-temperature firing of the β-sialons in the presence of NaF under a nitrogen atmosphere has been shown to cause no significant changes in the phase composition of the materials. The density and microhardness of the materials prepared using 0.5 and 5.0 wt

Composites have been prepared using nanopowders whose precursors were synthesized by a sol–gel hydrolysis process in 1 M solutions of the ZrOCl2, Al(NO3)3, Yb(NO3)3, and Sr (NO3)2 salts the amount of which corresponded to the basic composition (mol

α-tricalcium (α-TCP) phosphate is widely used as an osteoinductive biocompatible material, serving as an alternative to synthetic porous bone materials. The objective of this study is to obtain a highly filled fibrous nonwoven material composed of poly-3-hydroxybutyrate (PHB) and α-TCP and to investigate the morphology, structure, and properties of the composite obtained by the electrospinning method (ES). The addition of α-TCP had a significant effect on the supramolecular structure of the material, allowing it to control the crystallinity of the material, which was accompanied by changes in mechanical properties, FTIR spectra, and XRD curves. The obtained results open the way to the creation of new osteoconductive materials with a controlled release of the source of calcium into the living organism.

The article presents a method to synthesize aluminum oxynitride (AlON) doped with cobalt ions at concentrations ranging from 0.01 at.% to 5 at.%. The phase and elemental composition of the samples and their optical properties have been studied upon variation of the cobalt content. Five emission bands in the pulsed cathodoluminescence spectra are attributed to intrinsic defects and impurities in AlON. The optical gap of AlON:Co estimated using the Tauc method are in the range of 5.72–5.84 eV and are significantly influenced by the oxygen content in the AlON host.

Получены композиты на основе нанопорошков, прекурсоры которых синтезированы гидролизным золь–гель-методом из 1 М растворов солей ZrOCl 2 , Al(NO 3 ) 3, Yb(NO 3 ) 3 , Sr (NO 3 ) 2 , количество которых отвечало базовому составу (мол. %): 50 Al 2 O 3 , 50 – n 3Yb-TZP (тетрагональный диоксид циркония, стабилизированный 3% Yb 2 O 3 ) и модификатор SrO в количестве n = 1, 3 и 6%. Проведено исследование влияния количества модификатора на формирование фазового состава, микроструктуры и механические характеристики композитов. Установлено, что введение модификатора определяет смещение фазового перехода θ-Al 2 O 3 → α-Al 2 O 3 в область более высоких температур. Показано, что в процессе спекания исходных наноразмерных порошков in situ в температурном интервале 1250–1400°C происходит формирование фаз корунда и гексаалюмината стронция. Определено, что введение модификатора свыше 3% повышает закрытую пористость композитов, снижая параметр прочности с 700 до 450 МПа.