Inorganic Materials: Applied Research最新文献

The effect of preliminary irradiation with argon ions (energy of 20 keV, dose of 2.0 × 10²² m^–2, T_irr ∼ 700 K) and subsequent exposure to pulsed laser radiation (LR) with a power density of q ∼ 1.2 × 10¹² W/m², pulse duration τ₀ = 50 ns, and the number of pulses from 1 to 4 on the morphology and microhardness of the surface of V–10Ti–6Cr–0.05Zr–0.1Si vanadium alloy is studied. It is found that implantation of Ar⁺ ions in the specified mode leads to the formation of a porous (spongy) structure in the surface layers. It is shown that, as a result of the impact of pulsed LR, a common feature of the destruction of the surface layer of both the initial sample and the sample preliminarily irradiated with argon ions is the formation of a crater surrounded by a parapet. However, in the second case, the parapet is a ring-shaped rim, and there is practically no splashing of metal out of the crater. It is found that, as a result of ultrafast melting and crystallization, a fine-cell structure with a cell size of ∼200 nm is formed in the near-surface layers of samples implanted with Ar⁺ in the region of the crater. Behind the crater, there is a heat-affected zone (HAZ), into which the plasma cloud transfers part of its energy. It is established that, as a result of the combined effect of argon ions and pulsed laser radiation, typical structures are formed in the HAZ, being observed both for this alloy and for vanadium arising under the influence of LR under various modes of preliminary ion implantation. It is found that the microhardness of the surface layers after implantation of Ar⁺ ions into alloy increases slightly. After the impact of pulsed LR on both the initial and preliminarily implanted (by Ar⁺) alloy samples, the microhardness in the crater area first decreases, and then, with an increase in the number of pulsed impacts, a tendency towards its increase is observed. The mechanisms of the observed phenomena are discussed.

The interaction between platinum (Pt) and Chlorin e6 in aqueous solutions has been studied using luminescence and electron spectroscopic techniques. The potential for singlet oxygen formation and photodegradation of Chlorin e6 in the presence of platinum under red light has been investigated. It has been found that an aqueous solution of Chlorin e6 with platinum exhibits photodynamic activity, generating singlet oxygen more intensely than a solution of Chlorin e6 alone. Effective cell death has been observed in tumor cells of the Ehrlich ascites adenocarcinoma after one day of exposure to the Chlorin e6-Pt complex. A solution with a 1 : 0.5 molar ratio of Chlorin e6 to Pt has been identified as a promising candidate for a water-soluble anticancer agent with combined photodynamic and chemotherapeutic effects.

Hybrid materials based on carbon fabric modified with molybdenum oxides and polyvynylpirrolidone, synthesized by method of non-stationary electrolysis are studied. The main phases of hybrid materials according SAED data were molybdenum oxides MoO₃, Mo₄O₁₁, Mo₈O₂₃. The specific capacitance of hybrid materials was 985 mF/cm² at current density 5 mA/cm². Hybrid materials are characterized by capacitance retention on level 82% after 10 000 charge-discharge cycles.

In present paper 20 published models/equations for fracture toughness determination were analyzed by the following parameters: crack length after penetration, microhardness and fracture toughness of the ceramics. The following criteria were chosen to meet the practical use of the formulas for structural ceramics: (i) material hardness belongs to the range of 16–20 GPa with the maximum coverage of this range, (ii) c/a ratio lies in the range of 2.5–3, (iii) equation contains explicit and simple to measure parameters. Equations that meet all of these criteria were tested on composite ceramics based on alumina, zirconia and silicon nitride and it turned out that equation, proposed by Antstis et al. being simple, most cited and accounting the elastic-plastic characteristics of the material, suits best for such ceramics. At the same time equation by Evans and Wilshaw can be recommended when it is impossible to determine, for example, the elastic modulus of the material. Equation, derived by Niihara, Morena and Hasselman, appeared to fit best at low loads (<20 N) only where Palmquist crack system is formed.

The possibility of synthesis a water-soluble palladium complex with Chlorin e6 as part of the Photoditazine drug has been investigated. Based on data from electronic absorption and luminescence spectroscopy, it was concluded that a complex of palladium and Chlorin e6, with palladium located in a tetrapyrrole ring, was formed. In particular, it was found that the luminescence intensity and the wavelength of the Chlorin e6 band increased in solutions containing Chlorin e6 and palladium. Mass spectrometry analysis determined that the complex was [Pd : Chlorin e6]^2–. The complex of Chlorin e6 with palladium in a 0.5 : 1 molar ratio was identified as most promising for further research due to its rapid accumulation in tumor cells, low toxicity and minimal impact on cellular membrane integrity.

This paper presents the prediction of the phase composition and properties of a high-entropy CoCrFeMnNi alloy using the Calphad method and neural networks. The study emphasizes the importance of phase composition in determining the properties of materials, separating phases into solid solutions, intermetallic compounds, mixed phases, and amorphous structures. corrosion resistance. Traditional parametric and computational approaches are discussed, the role of rules of thumb and the potential of machine learning methods, in particular neural networks, in predicting mechanical properties such as microhardness, Young’s modulus, yield and strength strengths are emphasized. The research is aimed at creating effective methodologies for designing new alloys with optimal properties, identifying hidden patterns in large data sets, and thereby improving the efficiency of predicting the properties of complex materials.

The paper considers the possibility of cationic isomorphic substitutions for controlling and changing the properties of hydroxyapatite (HA). HA was synthesized by changing the concentration of Mg²⁺, Ca²⁺ ions and adding Zn²⁺ ions at physiological pH 7.45 ± 0.05 from a model solution of synovia. It was found that the synthesis carried out with an increase in the concentration of magnesium ions leads to the appearance of a new phase—whitlockite. A large volume of the unit cell and a variety of different structural positions determine the ability of whitlockite to a variety of isomorphism. This largely serves as a source of a wide range of functional properties inherent in compounds with this structural type. Synthesis carried out with a simultaneous increase in the concentration of Mg² ions and a decrease in the concentration of Ca²⁺ ions has a huge destabilizing effect on the formation of HA and leads to the formation of new phases: whitlockite, phosphate, oxide and hydroxide of magnesium. It has been established that synthesis with the introduction of small amounts of Zn²⁺ ions (up to 12 mg/L inclusive) does not affect the phase composition of the obtained samples, the amorphousness of the solid phase and the mass of the resulting sediments increase slightly, and the size of the crystallites decreases. Synthesis of new compounds with specified physical properties and chemical composition is a relevant and practical task.

This study examines the microstructure and properties of molybdenum-containing coatings deposited by non-vacuum electron beam cladding of molybdenum and amorphous boron powder mixtures. Chromium and titanium served as alloying elements in the experiments. The resulting coatings demonstrated thicknesses of 1.5–2 mm. The Mo-B coatings with chromium additions formed chromium-alloyed α-Fe solid solution along and Fe₃B-type borides, while titanium alloying produced α-Fe solid solution and Fe₂B borides. The chromium-modified MoBCr coatings exhibited superior hardness and high-temperature oxidation resistance compared to titanium-containing variants. The microhardness increased by a factor of 2.5 relative to AISI 5140 steel base material. The oxidation resistance of MoBCr coatings improved twofold through formation of dense Cr₂O₃-based oxide films that effectively block oxygen and metal ion diffusion during oxidation processes.

Tribological tests of a composite material based on the antifriction alloy AOM20-1 were carried out. The samples were produced using reaction casting, mixing titanium particles to form a structure with intermetallic strengthening. Dry sliding friction tests were carried out at sliding speeds from 0.25 to 0.75 m/s and loads from 0.5 to 3.0 MPa. A comprehensive comparison of the tribological properties of samples and friction processes (wear intensity, friction coefficient, stability index) was used. The loading conditions under which the material demonstrates the best set of characteristics have been determined: sliding speed of 0.5 m/s under a load of 1.5 MPa.

Using the Plasma Focus PF-5M device, damageability, erosion, and structural changes in the surface layers of tungsten single-crystal samples caused by exposure to pulsed electron beams are studied in comparison with pulsed irradiation by combined flows of helium ions and helium plasma with the following parameters: power density q_e = 5 × 10⁸ W/cm² for electrons; q_ipl = 1 × 10⁸ W/cm² for ion-plasma flow; pulse duration τ_e = 20 ns and τ_ipl = 50 ns, respectively; and the number of pulsed impacts N = 15. It is shown that, in the implemented irradiation mode, the melting of tungsten surface layer by ion-plasma flows occurs over the entire irradiation area and is noticeably stronger than by electron beams, the impact of which leads to very weak melting of individual local areas of the surface, which are island-like in character. After ion-plasma impact on the tungsten single crystal, a wavelike surface relief is formed, which contains blisters with undestroyed shell domes, microcracks located in mutually perpendicular directions, and pores. In the irradiated surface layer of tungsten, a transformation of the initial monocrystalline structure into a polycrystalline cellular structure is also observed. In the case of exposure of the tungsten single crystal to electron beams, two mechanisms of structural changes in the surface layer are established. One of them is related to the processes of melting and crystallization of the irradiated surface layer, which occur in its individual local areas and contribute to the formation of pores and microcracks. The second one is due to the solid-phase recrystallization process occurring as a result of thermal heating of a near surface layer deeper than the thickness of the melt, which is related to the release of energy during the scattering of the electron flow in the material. Under the influence of the resulting thermal stresses, a network of microcracks appears over the entire area of electron impact located along the slip lines of the crystallographic planes of the tungsten single crystal. The observed increased cracking of the surface layer of the studied tungsten single crystal contributes to the intensification of its erosion by sputtering and evaporation of the material under conditions of multiple radiation-thermal exposures.