scholarly journals POROUS PERMEABLE HIGH-ALUMINA CERAMIC MATERIALS FOR MACRO- AND MICROFILTRATION

2016 ◽  
Vol 7 (3) ◽  
pp. 146-150
Author(s):  
Yurij G. Pauliukevich ◽  
Olga Kizinievič ◽  
Yurij A. Klimash ◽  
Mikalai M. Hundzilovich ◽  
Giedrius Girskas
Keyword(s):  
Phase Composition ◽  
Acid Resistance ◽  
Ceramic Materials ◽  
Refractory Clay ◽  
High Alumina ◽  
Maximum Temperature ◽  
Average Pore ◽  
Dry Pressing ◽  
Porosity And Permeability ◽  
Binder Composition

Designed composition of ceramic mass for high-alumina porous permeable ceramic material for disperse micro hydro systems. The filler used alumina fraction 100–250 microns, as a binder system studied refractory clay Veselovskaya–medicalglass–gibbsite. Formation of material carried by dry pressing at a pressure 60 MPa, the temperature of synthesis was 1250–1350 °C, holding at the maximum temperature – 1 h. The processes occurring in the binder during sintering was investigated. The effect of the sintering temperature of the material, the amount of binder composition on the acid resistance, mechanical strength, porosity and permeability of open high-alumina permeable porous material was investigated. The structure and phase composition of the submissions received, the average pore diameter was 10 mm, it can be used for microfiltration of liquids and gases, the material is homogeneous at the macro level, the structure is represented by an extensive network of channels of pores. Phase composition is represented mainly corundum and mullite.

scholarly journals Properties dependence of the lightweight alumina products obtained by a semi-dry pressing method on the alumina type

2020 ◽  
Vol 120 ◽  
pp. 126-133
Author(s):  
V. V. Martynenko ◽  
Yu. A. Krakhmal ◽  
K. I. Kushchenko ◽  
T. G. Tishina
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
Pressing Method ◽  
Technical Requirements ◽  
Alumina Grade ◽  
Pitch Coke ◽  
Calcium Hexaluminate ◽  
Dry Pressing

Lightweight materials are widely used in industry for thermal insulation of various thermal units. The choice of lightweight material depends on the specific conditions of service. For the lining of high-temperature units operating in reducing environments, alumina lightweight products are used that contain a minimum amount of Fe2O3 impurities and free (unbound in compounds) SiO2. In JSC “URIR named after A. S. Berezhnoy” a technology of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by a semi-dry pressing method with an application temperature of up to 1550 °C has been developed. These products are made from a mixture of ground and no-milled γ-form alumina of grade 0 and α-form alumina of grade S with additives of pitch coke and chalk. The work purpose was improvement of the alumina lightweight products technology and search for new alternative raw materials along with the currently used alumina grade S. The properties dependence of alumina lightweight products, obtained by the semi-dry pressing method, on the type of alumina α-form, was investigated. As a result of the studies, it was found that, for the manufacture of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by the semi-dry pressing method, alumina grades N and NR can be used as an alternative alumina-containing raw material along with alumina grade S. The phase composition of alumina lightweight products of grades KLA-1.1 and KLA-1.3, which are manufactured using alumina grades S, N and NR, was represented mainly by corundum and calcium hexaluminate. The alumina lightweight products, which were manufactured using alumina grades S, N and NR, were characterized by similar high properties and correspond the technical requirements for grades KLA-1.1 and KLA-1.3.

Performance Comparison of Microchannel Heat Sink Using Boron-Based Ceramic Materials

2021 ◽  
Vol 1163 ◽  
pp. 73-88
Author(s):  
Md Tanbir Sarowar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Sink ◽  
Electronic Devices ◽  
Ceramic Materials ◽  
Substrate Material ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Microchannel Heat Sink ◽  
Small Surface

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.

The Preparation of High-Strength and Micropore Lightweight Bauxite Aggregate by In Situ Polymerization and Decomposition

2011 ◽  
Vol 194-196 ◽  
pp. 2135-2139
Author(s):  
Yi Neng Fang ◽  
Hua Zhi Gu ◽  
Yun Sheng Fen ◽  
Lin Jun Wang ◽  
Yan Jing Li
Keyword(s):  
Phase Composition ◽  
Pore Size ◽  
Aluminium Hydroxide ◽  
Average Pore Size ◽  
High Strength ◽  
Organic Polymer ◽  
Low Grade ◽  
Pore Former ◽  
Average Pore

High-strength and micropore lightweight bauxite aggregate was fabricated by low grade raw bauxite powder, aluminium hydroxide powder and organic polymer (OP). OP was used as consolidator, binder and pore former and aluminium hydroxide was used as pore former. The influence of OP and aluminium hydroxide content on the property of the samples was studied. The phase composition and the microstructure of the sintered samples were characterized by XRD, SEM and the pore size distribution was measured by mercury porosimety. The results demonstrate that the bulk density of the samples decreases linearly and the apparent porosity of the samples increases gradually with the addition of OP. The lowest density reached 1.13g/cm3when adding 35% OP and 10% Al(OH)3. The average pore size is around 5μm, and increases with the addition of OP increased. The XRD showed the main phase of the sample is mullite and some little amount of corundum.

scholarly journals New Feedstock System for Fused Filament Fabrication of Sintered Alumina Parts

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4461 ◽  
Author(s):  
Dorit Nötzel ◽  
Thomas Hanemann
Keyword(s):  
Injection Molding ◽  
Material Selection ◽  
Flow Behavior ◽  
Ceramic Materials ◽  
Maximum Temperature ◽  
Powder Injection ◽  
Fused Filament Fabrication ◽  
Sintered Ceramic ◽  
Whole Process ◽  
Dependent Flow

Only a few 3D-printing techniques are able to process ceramic materials and exploit successfully the capabilities of additive manufacturing of sintered ceramic parts. In this work, a new two component binder system, consisting of polyethyleneglycol and polyvinylbutyral, as well stearic acid as surfactant, was filled with submicron sized alumina up to 55 vol.% and used in fused filament fabrication (FFF) for the first time. The whole process chain, as established in powder injection molding of ceramic parts, starting with material selection, compounding, measurement of shear rate and temperature dependent flow behavior, filament fabrication, as well as FFF printing. A combination of solvent pre-debinding with thermal debinding and sintering at a reduced maximum temperature due to the submicron sized alumina and the related enhanced sinter activity, enabled the realization of alumina parts with complex shape and sinter densities around 98 % Th. Finally the overall shrinkage of the printed parts were compared with similar ones obtained by micro ceramic injection molding.

Multi-Purpose Porous Ceramic Material

2018 ◽  
Vol 931 ◽  
pp. 594-597
Author(s):  
Yu.S. Bagaiskov
Keyword(s):  
Ceramic Material ◽  
Construction Material ◽  
Porous Ceramic ◽  
Ceramic Composites ◽  
Refractory Clay ◽  
Treatment Processes ◽  
Wide Range ◽  
Porosity And Permeability ◽  
And Performance ◽  
Criteria For Evaluation

The main criteria for evaluation of ceramic products’ properties are strength, structural and mechanical, and thermophysical properties. To produce ceramic composites with a wide range of structural, mechanical, strength, and performance properties depending on application, various additives (flux agents, sintering agents, fillers) and heat treatment processes are used. Studies to determine a rational mixture composition have been carried out. A multipurpose material, comprising particles of the basic chamotte filler (burned clay) with a bonding agent in the form of refractory clay from the Latnenskoye deposit with a field spar fluxing agent, an additional filler made of heat-resistant silicon carbide, and an adhesive component in the form of powdered dextrin, is suggested. According to the combination of its ensured parameters, the obtained ceramic material can be multipurpose. Its degree of porosity and permeability make the material filtering, sound-proofing, and heat-retaining; considering the low density, it can be used as a lightweight construction material.

A Study on Structure and Phase Composition of Cellular Ceramic Materials from Dispersed Silica-Rich Rocks

2018 ◽  
Vol 284 ◽  
pp. 893-898
Author(s):  
Andrey Yu. Stolboushkin ◽  
A.I. Ivanov ◽  
O.A. Fomina
Keyword(s):  
Phase Composition ◽  
Cellular Structure ◽  
Solid Phase ◽  
Foam Glass ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Average Density ◽  
Crystalline Material ◽  
Pore Glass ◽  
Cellular Ceramic

Studies on structure, phase composition and properties of ceramic wall materials with a glass-crystalline framework from dispersed silica-rich rocks are described. The results of chemical, mineralogical and granulometric compositions of tripolite and granulated foam-glass crystalline material (GFGCM) are presented. The dependence of physical and mechanical properties of cellular ceramic materials on GFGCM content in the composition in the amount from 5 to 75% is determined. Test samples of cellular ceramic materials with dimensions 250 × 120 × 65 mm, having a compressive strength 16.2-20.8 MPa, water absorption 7.1-7.9 % and an average density 0.99-1.32 g/m3 were produced at the factory. At the macroscale level the cellular structure of the ceramic material consists of closed pores with a vitrified inner surface pore, glass-crystalline outer shell of the pores and solid phase of the framework walls. It was established that after firing in the temperature range 850-900 °C the walls of the framework are represented by quartz, feldspar and hematite, a pronounced halo is indicating a significant amount of glass phase.

Investigating the phase composition of fused high alumina (mullite) refractories

Refractories ◽  
1965 ◽  
Vol 6 (1-2) ◽  
pp. 78-82 ◽  
Author(s):  
S. F. Rustambekyan ◽  
N. V. Solomin
Keyword(s):  
Phase Composition ◽  
High Alumina
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