scholarly journals THE INFLUENCE OF ELEMENTAL POWDER RAW MATERIAL ON THE FORMATION OF THE POROUS FRAME OF TI3ALC2 MAX-PHASE WHEN OBTAINING BY THE SHS METHOD

2021 ◽  
pp. 37-47
Author(s):  
D. M. Davydov ◽  
◽  
E. R. Umerov ◽  
E. I. Latukhin ◽  
A. P. Amosov ◽  
...  
Keyword(s):  
Size Fraction ◽  
Graphite Powder ◽  
Ceramic Materials ◽  
Sample Volume ◽  
External Pressure ◽  
Raw Material ◽  
Max Phase ◽  
Stoichiometric Ratio ◽  
Shape Distortion ◽  
Porous Frame

The ternary carbide compound Ti3AlC2 belongs to the so-called MAX-phases – a new type of ceramic materials with unique properties. A simple energy-saving method of self-propagating high-temperature synthesis (SHS) based on combustion is one of the promising methods for the production of this MAX-phase. The application of the SHS technology is to produce a Ti3AlC2 MAX-phase porous frame with the homogeneous porous structure without such defects as large pores, laminations, and cracks is of great interest. The paper investigates the possibility of producing such a porous frame with the maximum content of the Ti3AlC2 MAX-phase using powders of Ti, Al, and C elements of various grades different in particle sizes and carbon forms (soot or graphite) as initial components. Porous frame samples were produced by the open-air burning of pressed briquettes of charge of the initial powders of the selected grades without applying external pressure. The authors studied the macro- and microstructure of the obtained samples, their density, and phase composition. The study shows that using the finest titanium and carbon powders leads to the excessively active combustion with gas evolution and the synthesis of the defective porous samples with the charge briquette shape distortion, large pores, laminations, and cracks. Besides the titanium carbide by-phase, the highest values for the MAX-phase amount in the SHS-product were obtained using the titanium powder of the largest-size fraction together with the graphite powder, rather than soot. The excess aluminum powder addition to the stoichiometric ratio to the initial charge leads to an increase in the MAX-phase amount in the SHS product, compensating for the loss of aluminum due to evaporation. An increase in the sample volume (scale factor) also leads to an increase in the MAX-phase amount in the SHS product due to the slower cooling of the product after the reaction.

scholarly journals Injection Molding and Near-Complete Densification of Monolithic and Al2O3 Fiber-Reinforced Ti2AlC MAX Phase Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3632
Author(s):  
Sylvain Badie ◽  
Rimy Gabriel ◽  
Doris Sebold ◽  
Robert Vaßen ◽  
Olivier Guillon ◽  
...  
Keyword(s):  
Injection Molding ◽  
Graphite Powder ◽  
Max Phase ◽  
Powder Injection ◽  
Fiber Reinforced ◽  
Ceramic Fibers ◽  
Plasma Sintering ◽  
Molded Parts ◽  
Al2o3 Fiber ◽  
Induced Velocity

Near-net shape components composed of monolithic Ti2AlC and composites thereof, containing up to 20 vol.% Al2O3 fibers, were fabricated by powder injection molding. Fibers were homogeneously dispersed and preferentially oriented, due to flow constriction and shear-induced velocity gradients. After a two-stage debinding procedure, the injection-molded parts were sintered by pressureless sintering at 1250 °C and 1400 °C under argon, leading to relative densities of up to 70% and 92%, respectively. In order to achieve near-complete densification, field assisted sintering technology/spark plasma sintering in a graphite powder bed was used, yielding final relative densities of up to 98.6% and 97.2% for monolithic and composite parts, respectively. While the monolithic parts shrank isotropically, composite assemblies underwent anisotropic densification due to constrained sintering, on account of the ceramic fibers and their specific orientation. No significant increase, either in hardness or in toughness, upon the incorporation of Al2O3 fibers was observed. The 20 vol.% Al2O3 fiber-reinforced specimen accommodated deformation by producing neat and well-defined pyramidal indents at every load up to a 30 kgf (~294 N).

scholarly journals Treatment of Soil Contaminated by Mining Activities to Prevent Contamination by Encapsulation in Ceramic Construction Materials

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6740
Author(s):  
Juan María Terrones-Saeta ◽  
Jorge Suárez-Macías ◽  
Antonio Bernardo-Sánchez ◽  
Laura Álvarez de Prado ◽  
Marta Menéndez Fernández ◽  
...  
Keyword(s):  
Ceramic Material ◽  
Contaminated Soil ◽  
Toxic Elements ◽  
Construction Materials ◽  
Well Being ◽  
Ceramic Materials ◽  
Potentially Toxic Elements ◽  
Raw Material ◽  
Mining District ◽  
Different Soils

Mining is an essential activity for obtaining materials necessary for the well-being and development of society. However, this activity produces important environmental impacts that must be controlled. More specifically, there are different soils near new or abandoned mining productions that have been contaminated with potentially toxic elements, and currently represent an important environmental problem. In this research, a contaminated soil from the mining district of Linares was studied for its use as a raw material for the conforming of ceramic materials, bricks, dedicated to construction. Firstly, the contaminated soil was chemically and physically characterized in order to evaluate its suitability. Subsequently, different families of samples were conformed with different percentages of clay and contaminated soil. Finally, the conformed ceramics were physically and mechanically characterized to examine the variation produced in the ceramic material by the incorporation of the contaminated soil. In addition, in this research, leachate tests were performed according to the TCLP method determining whether encapsulation of potentially toxic elements in the soil occurs. The results showed that all families of ceramic materials have acceptable physical properties, with a soil percentage of less than 80% being acceptable to obtain adequate mechanical properties and a maximum of 70% of contaminated soil to obtain acceptable leachate according to EPA regulations. Therefore, the maximum percentage of contaminated soil that can be incorporated into the ceramic material is 70% in order to comply with all standards. Consequently, this research not only avoids the contamination that contaminated soil can produce, but also valorizes this element as a raw material for new materials, avoiding the extraction of clay and reducing the environmental impact.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF GREENER CERAMIC MATERIALS WITH LOWER THERMAL CONDUCTIVITY USING OLIVE MILL SOLID BYPRODUCT

2020 ◽  
Vol 1 ◽  
pp. 96-106 ◽  
Author(s):  
Xenofon Spiliotis ◽  
Vayos Karayannis ◽  
Stylianos Lamprakopoulos ◽  
Konstantinos Ntampegliotis ◽  
George Papapolymerou
Keyword(s):  
Thermal Conductivity ◽  
Solid Waste ◽  
Energy Savings ◽  
Sintering Temperature ◽  
Ceramic Body ◽  
Ceramic Materials ◽  
Raw Material ◽  
Gravimetric Analysis ◽  
Olive Mill Solid Waste ◽  
Olive Mill

In the current research, the valorization of olive mill solid waste as beneficial admixture into clay bodies for developing greener ceramic materials with lower thermal conductivity, thus with increased thermal insulation capacity towards energy savings, is investigated. Various clay/waste mixtures were prepared. The raw material mixtures were characterized and subjected to thermal gravimetric analysis, in order to optimize the mineral composition and maintain calcium and magnesium oxides content to a minimum. Test specimens were formed employing extrusion and then sintering procedure at different peak temperatures. Apparent density, water absorption capability, mechanical strength, porosity and thermal conductivity were determined on sintered specimens and examined in relation to the waste percentage and sintering temperature. The experimental results showed that ceramic production from clay/olive-mill solid waste mixtures is feasible. In fact, the mechanical properties are not significantly impacted with the incorporation of the waste in the ceramic body. However, the thermal conductivity decreases significantly, which can be of particular interest for thermal insulating materials development. Furthermore, the shape of the produced ceramics does not appear to change with the sintering temperature increase.

Ceramic Composition Material with Mullite Crystals Obtained from the Clayy Raw Material of Yakutia

2020 ◽  
Vol 992 ◽  
pp. 253-258
Author(s):  
M.P. Lebedev ◽  
V.N. Tagrov ◽  
E.S. Lukin
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
Practical Interest ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Strength Properties ◽  
Raw Material ◽  
Composition Material ◽  
Material Base ◽  
Wide Range

The article deals with the manufacture of modern structural ceramic materials from clay and loam deposits of the Republic of Sakha (Yakutia). The importance and relevance of the development of the production of building materials from local raw materials is emphasized, since this will certainly affect the effectiveness of the construction complex as a whole. The successful development of the construction complex is capable of not only stimulating growth in all sectors of the economy, but also contributes to solving the most pressing social problems. Today, Yakutia has huge reserves of mineral raw materials for the production of a wide range of building materials and products. Of practical interest are wall materials made from clay soils. Given the features of the region’s raw material base, this work focuses on additional processing of traditional material. Controlling the complex physicochemical and structural-mechanical transformations that occur during heat treatment, a methodology has been developed for creating a composite material that will allow competitive innovative materials with enhanced strength properties to be produced with a reinforcing element with a glassy phase matrix of mullite crystals. The fabricated samples have a wide range of physical and mechanical properties and allow using it as a high-quality structural building ceramics, as well as industrial floor technical tile.

Effect of Si3N4-Y2O3 Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

2011 ◽  
Vol 335-336 ◽  
pp. 713-716
Author(s):  
Shu Long Liu ◽  
Zhi Fa Wang ◽  
Jing Long Bu ◽  
Shu Bin Shen ◽  
Li Xue Yu
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Quartz Ceramic ◽  
Apparent Porosity ◽  
Raw Material ◽  
Expansion Rate ◽  
Obvious Effect ◽  
Fused Quartz

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Y2O3 (1:1, in mass) was used as additive with dosages of 1%, 2% and 3% (in mass). Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The effect of Si3N4-Y2O3 on crystallization and sintering of the fused quartz ceramic materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate (RT~1200 °C), and by the analyses of XRD and SEM. The results showed that the samples sintered at each temperature with 3% Si3N4-Y2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Y2O3 was conducive to sintering of fused quartz ceramic materials. The results of XRD and thermal expansion rate showed that addition of 3% Si3N4-Y2O3 compound had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the Si3N4-Y2O3 compound plays the best role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

scholarly journals Hydrothermal Corrosion Behaviors of Constituent Materials of SiC/SiC Composites for LWR Applications

Ceramics ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 602-611
Author(s):  
Shoko Suyama ◽  
Masaru Ukai ◽  
Megumi Akimoto ◽  
Toshiki Nishimura ◽  
Satoko Tajima
Keyword(s):  
Corrosion Resistance ◽  
Residual Strength ◽  
Pure Water ◽  
Operating Conditions ◽  
Raw Material ◽  
Stoichiometric Ratio ◽  
Sic Fibers ◽  
Corrosion Behaviors ◽  
Fiber Matrix ◽  
Sic Composites

The corrosion behaviors of SiC/SiC composite constituent materials in pure water at operating conditions, such as 300 °C and 8.5 MPa, were studied for potential application in accident-tolerant light water reactor (LWR) fuel cladding and core structures. Five kinds of SiC fibers, four kinds of SiC matrices, and three kinds of fiber/matrix interphase materials were examined in autoclaves. The potential constituent materials for future use in SiC/SiC composites were selected by considering corrosion rates and residual strength characteristics. The mass changes and the residual strength of each specimen were measured. SEM images of the surface layers were also inspected. The SiC fibers, regardless of their purity, crystallinity or stoichiometric ratio, decreased in strength due to the hydrothermal corrosion. For its part, the hydrothermal corrosion resistance of CVD-SiC, as a SiC matrix, was found to be affected by manufacturing conditions such as raw material gas type and synthesis temperature, as well as post-machining morphology. The CVD-carbon (CVD-C), as a fiber/matrix interphase material, showed good hydrothermal corrosion resistance. In order to protect the SiC fibers and the SiC matrices from hydrothermal corrosion, it would appear to be necessary to apply a dense CVD-C coating to both every fiber and the entire surface of the SiC matrices.

scholarly journals Industrial Ceramic Blocks for Buildings: Clay Characterization and Drying Experimental Study

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2834
Author(s):  
A.M. Vasconcelos da Silva ◽  
J.M.P.Q. Delgado ◽  
A.S. Guimarães ◽  
W.M.P. Barbosa de Lima ◽  
R. Soares Gomez ◽  
...  
Keyword(s):  
Mass Loss ◽  
Particle Diameter ◽  
Ceramic Materials ◽  
Raw Material ◽  
Average Particle ◽  
Ceramic Block ◽  
Ceramic Blocks ◽  
Dimensional Variation ◽  
Forced Air ◽  
Air Circulation

The conformation of a ceramic piece follows the steps of preparing the raw material, molding, lamination, drying, and firing. Drying is a thermodynamic process of heat and mass transfer, with dimensional variations of the product that requires a large amount of energy. Ceramic materials when exposed to non-uniform drying may suffer cracks and deformations, reducing their post-drying quality. Thus, this work aimed to study the drying of industrial ceramic blocks in an oven with forced air circulation. Experiments were carried out to characterize the clay and drying of the ceramic block at temperatures ranging from 50 °C to 100 °C. Results of the chemical, mineralogical, granulometric, differential thermal, and thermogravimetric analysis of the clay, and heating kinetics, mass loss, and dimensional variation of the industrial ceramic block are presented and analyzed in detail. It was found that the clay is basically composed of silica and alumina (≈ 80.96%), with an average particle diameter of 13.36 μm. The study proved that drying at high temperature and low relative humidity of the air generates high rates of mass loss, heating, and volumetric shrinkage in the ceramic product, and high thermo-hydraulic stresses, which cause the appearance and propagation of cracks, gaps, and cleavages, compromising the final quality of the product.

Preparation of Self-Releasing Glaze Ceramic Materials Utilizing Red Mud

2011 ◽  
Vol 383-390 ◽  
pp. 3366-3373
Author(s):  
Shuo Qin ◽  
Bo Lin Wu ◽  
Shiao Zhao ◽  
Cong Chang Ma ◽  
Zu Sheng Hu
Keyword(s):  
Mechanical Properties ◽  
Red Mud ◽  
Barium Carbonate ◽  
Raw Materials ◽  
Normal Pressure ◽  
Ceramic Materials ◽  
The Self ◽  
Raw Material ◽  
Radiation Level ◽  
Red Sandstone

Red mud is the main solid residue generated during the production of alumina by means of the Bayer process. In order to expand the comprehensive utilization field of red mud and develop new ceramic products with low radioactivity utilizing red mud, the exploration of preparing self-releasing glaze ceramic materials using red mud as raw material was carried out. During the exploration, the self-releasing glaze ceramic materials with low radiation level were produced by normal pressure sintering process using the main ingredients of red mud, red sandstone, barium carbonate and ball clay. The properties of the self-releasing glaze ceramic samples were investigated by the measurements of mechanical properties, X-ray diffraction (XRD), scanning electron microscopy (SEM) and radiation measurement. The results show that the self-releasing glaze ceramic materials have good mechanical properties (the bulk density, 3.10 g/cm3; the compressive strength, 78.00 MPa). Adding barium carbonate to the raw materials and then calcine them to ceramics, which can extend the sintering temperature range and the radioactivity level of the self-releasing glaze ceramic materials can be reduced to that of the natural radioactive background of Guilin Area, Karst landform (the average 60 Total/Timer).

The Use of Carbonate Sludge in the Production of Porous Aggregate

2020 ◽  
Vol 24 (6) ◽  
pp. 15-19
Author(s):  
A.V. Kolpakov ◽  
E.S. Abdrakhimova
Keyword(s):  
Industrial Waste ◽  
Liquid Glass ◽  
Glass Composition ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Environmental Safety ◽  
Raw Material ◽  
Material Base ◽  
Carbonate Sludge ◽  
The Russian Federation

The possibilities of obtaining porous fillers based on carbonate sludge and liquid-glass composition are considered. One of the issues of industrial waste disposal is the creation of waste-free technologies. The use of nanotechnology-based carbonate sludge in the production of porous aggregates increases environmental safety. A porous aggregate with high physical and mechanical properties was obtained. The use of carbonate sludge in the production of porous aggregate contributes to: a) recycling of industrial waste; b) environmental protection; C) expanding the raw material base for obtaining ceramic materials for construction. A patent of the Russian Federation was obtained for the obtained method of producing a porous aggregate using a liquid-glass composition.

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