PRODUCTION OF POROUS GLASS-CRYSTALLINE MATERIALS BASED ON GLASS CULLET AND CONVERTER SLAG

The study conducted the research aimed to obtaining a porous glass-crystalline materials based on glass cullet and converter slag, which was used as a gas-forming additive. In this work, the chemical and phase compositions of the studied slag were analyzed, and a differential thermal analysis of its sample was carried out. Converter slag was added to the composition of the masses in an amount of 2.5 to 30 wt%, the rest was glass cullet. Вurning of the samples was carried out in the temperature range of 850-925 ° C. For the samples under study, using a sand volumetric meter, the volume was determined and the swelling coefficient was calculated, the compressive strength was determined, and the type of structure, which depends on the average diameter of the prevailing pores, was analyzed. The dependence of the swelling coefficient of the investigated materials on the burdening composition and burning temperature has been established. To obtain porous materials with a swelling coefficient of 2.16-2.67 and uniform fine-porous structure (predominant pore size less than 0.5 mm), it is optimal to introduce converter slag into the composition of the masses in an amount of 10-15 wt%, and the recommended temperature range their burning 850-900 ° C. Analysis of the phase composition of the materials obtained indicates the presence of wollastonite as the main crystalline phase, which, due to the acicular structure of the crystals, has a reinforcing effect and contributes to an increase in strength characteristics. The developed porous glass-crystalline materials can be used as thermal insulation and aggregates in lightweight concrete.

Effect of Basicity on the Microstructure of Sinter and Its Application Based on Deep Learning

The influence of the evolution rule of basicity (0.6∼2.4) on the mineral composition and microstructure of sinter is studied by using a polarizing microscope, and the comprehensive application analysis of the drum index, vertical sintering speed, and yield of sinter shows that, over the course of an increase in basicity (0.6∼1.0), the mineral structure changed from the original porphyritic-granular structure to a porphyritic structure. At the same time, there was no calcium ferrite phase in the bonding phase at a basicity of less than 1.0; therefore, the downward trend of the three indicators is obvious. When the basicity was further increased to approximately 1.6, the main structure of the mineral phase changed from a corrosion structure to an interweaving corrosion structure. Because of the existence of a porphyritic-granular structure, the structure of the mineral phase was extremely inhomogeneous and most complex near the basicity of 1.6; although a small amount of calcium ferrite displayed an acicular structure, the drum index appeared to show a very low value. With an increase in basicity to 2.0, the mineral phase structure was dominated by an interweaving corrosion structure with a uniform framework, and the content of calcium ferrite reached the highest value. Moreover, a clear acicular structure developed, and the drum index also increased to the highest value. At a basicity of more than 2.0, a mineral structure began to appear and the corrosion, porphyritic-granular structure, and the drum index also showed a slightly declining trend. Therefore, in the actual production process, basicity should be avoided as far as possible at around 1.0 and 1.6 and it should be controlled at around 2.0. At the same time, based on the mineral facies data set of this paper, the convolutional neural network is used to carry out a simple prediction model experiment on the basicity corresponding to the mineral facies photos, and the effect is quite good, which provides a new idea and method for the follow-up study of mineral facies.

Analysis of the Synthetic Fiber Influence on the Cement Stone New Formations Composition in Foam Concrete

The relevance of the search for scientifically grounded tools, with the help of which it is possible to ensure the growth of crack resistance and strength of foam concrete, is noted. The systemic need of the building complex for energy-and resource-saving operationally reliable building materials is emphasized. The positive influence of the surface energy potential of the fibrous fiber of polymer and carbon composition on the possibility of forming an improved structure of the cement stone in the composition of the interpore partitions of foam concrete has been scientifically substantiated. The article provides information on the foam mixtures formulation and the timing of their hardening. The scans of the investigated materials’ X-ray diffraction patterns and the identification table of the detected hydration neoplasms of the cement stone are presented. The scientific substantiation reliability is experimentally confirmed by the results of the analysis performed, from which it follows that all foam concretes contain quartz, portlandite, hydro-aluminates and calcium hydro-silicates. It has been established that the introduction of fiber into the foam mixture formulation creates the prerequisites for the appearance of such varieties of the hydrated silicate phase as nekoite, which has a fibrous structure at the nanoscale, and foshagite, which has an acicular structure of crystals with increased hardness. The listed mineral hydrated new formations of cement stone, due to their individual properties, should contribute to the foam concrete operational properties’ improvement.

Investigation of the variation in the size of samples made of 5СNM steel under thermal diffusion saturation with powder mixtures containing boron and copper

The change in the dimensions of parts after diffusion saturation of alloyed steel 5KhNM with boron and copper is investigated. Diffusion layers obtained on samples with different compositions of the saturating mixture are described. It is shown that when carrying out experiments on saturation of samples in a medium of powders with boron and copper, diffusion layers with an acicular structure with a thickness of 220...330 μm are obtained, and the increase in the observed size was from 44 to 135 μm, depending on the composition of the powder mixture. The properties of diffusion layers have been studied, including the distribution of microhardness and chemical elements at different distances from the surface.

Architecture, Growth Dynamics and Biomineralization of Pulsed Sr-Labelled <i>Katelysia rhytiphora</i> (Mollusca, Bivalvia)

We use pulsed Sr-labelling experiments to visualize growth of aragonitic Katelysia rhytiphora (Mollusca, Bivalvia) shells. The outer compound composite prismatic structure is organized into three orders of prisms, and the inner crossed acicular structure consists of intersecting lamellae. Electron Backscatter Diffraction (EBSD) reveals substantial twinning of the aragonite crystals (> 46 %) and an overall reduced and strategically oriented anisotropy of the Young’s modulus in the whole shell compared to that of monolithic aragonite. All structural orders in both layers are enveloped by an organic sheath and the smallest mineralized units are nanogranules. Total organic contents are 2.2 (outer) and 1.4 wt. % (inner layer) and are, thus, intermediate between those of nacreous and crossed-lamellar shells. Prisms in the outer structure can be correlated to yearly, daily and sub-daily growth rates. Average daily growth rates at the ventral margin for the outer structure are 17 % higher than for the inner crossed acicular structure. The calcification front runs evenly across all structures and architectural orders independently of the current growth rate. Sharply defined transitions from labelled to unlabelled areas in the shell indicate that physiological processes driving calcification have no lag. This suggests that the extrapallial fluid cannot be very voluminous. Narrow increments of varying Sr content within labelled shell, despite constant Sr concentrations in seawater, suggest cyclic metabolic activity during calcification. Micro-Raman spectroscopy maps validate a low impact of high Sr-conditions on the aragonite crystal structure. Identical Sr-enrichment factors for labelled and ambient conditions support models of ion transport via a passive selective pathway to the mantle epithelium followed by calcification via amorphous calcium carbonate.

Self-Supported NiSe/Ni Foam: An Efficient 3D Electrode for High-Performance Supercapacitors

Three-dimensional (3D) mixed phases NiSe nanoparticles growing on the nickel foam were synthesized via a simple one-step hydrothermal method. A series of experiments were carried out to control the morphology by adjusting the amount of selenium in the synthetic reaction. Meanwhile, the as-prepared novel column-acicular structure NiSe exist three advantages including ideal electrical conductivity, high specific capacity and high cycling stability. It delivered a high capacitance of 10.8[Formula: see text]F[Formula: see text]cm[Formula: see text] at a current density[Formula: see text] of 5[Formula: see text]mA[Formula: see text]cm[Formula: see text]. An electrochemical capacitor device operating at 1.6[Formula: see text]V was then constructed using NiSe/NF and activated carbon (AC) as positive and negative electrodes. Moreover, the device showed high energy density of 31[Formula: see text]W[Formula: see text]h[Formula: see text]kg[Formula: see text] at a power density of 0.81[Formula: see text]kW[Formula: see text]kg[Formula: see text], as well as good cycling stability (77% retention after 1500 cycles).

The Structure and Phase Composition of the Diffusion Zone in a Titanium and Steel Composite

An investigation is performed on the influence of the temperature and duration of heating of the explosively welded titanium ВТ1-0+ Steel 20 composite on the phase composition of the diffusion layer formed at the interface. It is shown that after heating to 800 oС the diffusion layer consists of α + α’-Ti , an iron solid solution in titanium and a decarburized zone. When heated at the temperature range from 900 – 1000 oС, the composition of the diffusion layer is as follows: α + α’-Ti acicular structure, Fe2Ti and FeTi intermetallics, TiC titanium carbide, titanium solid solution in α-Fe and a decarburized zone.

Fabrication of Multi-Layered Ti-Ta-Zr Coatings by Non-Vacuum Electron Beam Cladding

In this study Ti-Ta-Zr coatings fabricated on VT1-0 titanium substrates by non-vacuum electron beam cladding in one, two and three passes were investigated. Coatings were characterized by a high quality; such defects as cracks and voids were not observed. The structure of coating was commonly dendritic. The acicular structure in the one-layered coating and in the first layer of multilayered coatings was revealed by using scanning electron microscopy (SEM). The results of the energy dispersive X-ray (EDX) analysis indicated the presence of tantalum and zirconium segregations in dendrite arms and in the space between them. It was found that dendritic branches contained the maximum of tantalum while an increased amount of zirconium was concentrated in the interdendritic space. The maximum concentration of alloying elements (56.87 wt. % Ta and 22.22 wt. % Zr) was obtained in the layer cladded in the third pass of an electron beam. The microhardness of Ti-Ta-Zr layers rose from 4.5 GPa to 6 GPa with an increase in .the percentage of alloying elements

Formation of TiC0.3N0.7/TiN Composite Film on Ti-6Al-4V Alloy by YAG Laser Irradiation

TiC0.3N0.7/TiN composite film was successfully formed on the surface of Ti-6Al-4V alloy by the treatment of YAG laser irradiation. In this paper an influence of laser output power on microstructure, chemical composition, element distribution and hardness, which were separately analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and nanoindentation hardness test, was investigated. Results showed that cross-section microstructure as-observed near the surface can be divided into three areas which were TiC0.3N0.7/TiN composite film, acicular structure and coarsening area, respectively. With increasing the output power, the thickness and the hardness of the TiC0.3N0.7/TiN layer were significantly improved.