Characterization of planer cathode-supported SOFC prepared by a dual dry pressing method

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.

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Researches on development of alumina-chromia-zirconium silicate refractories containing 60 % Cr2O3

Scientific research on refractories and technical ceramics ◽

10.35857/2663-3566.120.02 ◽

2020 ◽

Vol 120 ◽

pp. 12-28

Author(s):

P. O. Kushchenko ◽

V. V. Primachenko ◽

I. G. Shulyk ◽

Yu. Ye. Mishnyova ◽

K. I. Kushchenko ◽

...

Keyword(s):

Corrosion Mechanism ◽

Pressing Method ◽

Refractory Structure ◽

Oxide Addition ◽

Zirconium Silicate ◽

Cold Crushing Strength ◽

Cr2o3 Content ◽

Corrosive Effect ◽

Dry Pressing ◽

Shock Resistance

Researches of a branch composition and firing atmosphere influence on structure and properties of pressed alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content were carried out. The optimal branch composition which after firing in oxidizing atmosphere provides obtaining of samples with open porosity 24.8 %, apparent density 3.46 g/cm3, cold crushing strength 78 N/mm2 and thermal shock resistance by 950 ºС — water — 7 thermal cycles was established. The phase composition of samples was determined. It has been shown that, firing in a reducing atmosphere, as well as titanium oxide addition, have no significant effect on samples properties. Corrosion resistance comparative researches of alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content and refractory brand KHTSS-30 with 30 % Cr2O3 content to glass «E» and basalt melts by crucible method at a temperature of 1580 °C with an exposure time of 8 hours were carried out. It has been established that, glass «E» and basalt impregnate refractories, moreover for samples with the developed optimal composition the impregnation depth was the smallest in comparison with samples of other compositions. The corrosion mechanism has been established, which consists in the penetration of glass «E» and basalt melts into refractory with further dissolution of corundum grains in them. Sintered Cr2O3 and solid solutions based on it in the composition of samples prevent corrosion, reducing the interaction area of melts with corundum grains, and when exposed to basalt melt, also forming spinelid with its components, which slows down further penetration of melt into refractory structure, thereby reducing its corrosive effect on the refractory. Based on the obtained results, a technology of a new domestic type of product (alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content manufactured by semi-dry pressing method) was developed.

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Effect study of an amount of active alumina addition on the properties of alumina refractories with a complex additive of chromium oxide and zirconium dioxide

Scientific research on refractories and technical ceramics ◽

10.35857/2663-3566.120.01 ◽

2020 ◽

Vol 120 ◽

pp. 3-11

Author(s):

I. G. Shulik ◽

T. G. Galchenko ◽

E. B. Protsak ◽

L. V. Belik

Keyword(s):

Chromium Oxide ◽

Zirconium Dioxide ◽

Effect Study ◽

Pressing Method ◽

Complex Additive ◽

Active Alumina ◽

Cold Crushing Strength ◽

Dry Pressing ◽

Alumina Addition ◽

Carbon Black Production

An effect of active alumina amount introduced into a batch (7.5 - 22.0 %) on the properties of alumina samples containing a complex additive of chromium oxide (10 %) and zirconium dioxide (3 %) was studied. The optimal amount of introduced active alumina (12.5 %) was established, which ensures the production of samples fired at a temperature of 1580 ºС, with the lowest open porosity (18.2 %), the highest apparent density (3.25 g/cm3) and the highest cold crushing strength (117 N/mm2), refractoriness under a load of 0.2 N/mm2 > 1700 ºС, thermal shock resistance (in the mode of 1300 ºС — water) not less than 7 thermal cycles.The results of carried out studies were used in the development of production technology of domestic refractory products based on fused corundum, α-form alumina, active alumina, containing the complex addition of chromium oxide and zirconium dioxide, by semi-dry pressing method. These refractory products characterized by high properties and intended for service at a temperature of 1850 ºС in the combustion chamber of carbon black production reactors.The use of these refractories in the lining of above mentioned high-temperature industrial units will allow to increase a duration of their operation due to an increase in the refractory durability in service, as well as to save material and energy resources associated with a relining of the reactors.

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Effect of Forming Technology on the Properties of Quartz Sands Porous Materials via Dry Pressing Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.861.244 ◽

2020 ◽

Vol 861 ◽

pp. 244-249

Author(s):

Yue Ning Qin ◽

Hao Xu ◽

Zhou Yang ◽

Shou Xia Yang ◽

Xue Qing Yang ◽

...

Keyword(s):

Porous Materials ◽

Ball Milling ◽

Quartz Sand ◽

Low Grade ◽

Pressing Method ◽

Forming Technology ◽

Pressure Time ◽

Quartz Sands ◽

Dry Pressing ◽

Sintering Method

The effect of forming technology on the properties of quartz sand porous materials were researched with the low grade quartz sand along the Yangtze River via the pressureless sintering method in this paper, which lay technology foundation for researching new heat insulating materials. The wear of ball milling media is investigated through adjusting the ball milling parameter via the weigh methods. The results are shown that the porosity of quartz sand porous materials are decreased with increasing a forming pressure. The porosities of Φ30 and Φ50 materials are decreased with increasing a holding pressure time, however, the porosity decreasing rate of Φ30 is slower than that of Φ50. The porosity of Φ50 is higher than that of Φ30 under same forming conditions. Through optimized the forming conditions, the porosity of sintered Φ50 quartz matrix porous materials reaches 54.52% under the forming pressure for 5MPa and the holding pressure time for 5min.

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The Press Powder Technological Parameters Optimization in Wall Ceramics Production by the Semi-Dry Pressing Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.974.419 ◽

2019 ◽

Vol 974 ◽

pp. 419-423

Author(s):

Victoria Gurieva ◽

A.V. Doroshin

Keyword(s):

Raw Materials ◽

Parameters Optimization ◽

Pressing Pressure ◽

Technological Parameters ◽

Press Powder ◽

Pressing Method ◽

Ash And Slag Waste ◽

Fundamental Possibility ◽

The Press ◽

Dry Pressing

The paper presents the fundamental possibility of using ash and slag waste (ASW) of the fuel and energy complex in the production of ceramic bricks using the semi-dry pressing method based on the Buguruslan deposit low-melting aluminosilicate loams. The technological parameters optimization ways (molding moisture, grinding fineness, pressing pressure) in the production of ceramic bricks from low-quality clay raw materials using the experiment mathematical planning method are presented. The separate and joint grinding raw materials mixture rational composition influence on the ceramics technological properties is studied.

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Syntheses and Characterization of Bulky Mesoporous Silica MCM-41 by Hydrothermal Hot-Pressing Method

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.47.2103 ◽

2006 ◽

Vol 47 (8) ◽

pp. 2103-2105 ◽

Cited By ~ 15

Author(s):

Hidezumi Nagata ◽

Mari Takimura ◽

Yuki Yamasaki ◽

Atsushi Nakahira

Keyword(s):

Mesoporous Silica ◽

Hot Pressing ◽

Pressing Method ◽

Mcm 41

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Characteristics of Wall and Floor Tiles Using Waste Glass

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.317-318.755 ◽

2006 ◽

Vol 317-318 ◽

pp. 755-758

Author(s):

Young Kil Kim ◽

Yeon Gil Jung ◽

Jun Baek Song ◽

Min Chul Shin ◽

Hee Soo Lee

Keyword(s):

Compressive Strength ◽

Bulk Density ◽

Firing Temperature ◽

Waste Glass ◽

Glass Content ◽

Pressing Method ◽

Abrasion Loss ◽

Floor Tiles ◽

Dry Pressing ◽

Clay Tiles

Wall and floor tiles were fabricated by a dry pressing method using waste glass and clay. The properties of the tiles such as absorption, bulk density, porosity, compressive strength, and abrasion loss are investigated with the firing temperature and glass content. The properties are improved with increasing both the firing temperature and glass content. These properties, except the compressive strength, tend to be saturated from the glass contents of 70 wt % in the case of 1050 . The compressive strength shows the maximum values at the glass contents of 70 wt% and then which are decreased with increasing the glass contents. The optimal properties obtained in the tiles are the water absorption of about 0.9 %, the bulk density of about 2.3 g/cm3, the apparent porosity of about 2.1 %, the compressive strength of about 210 MPa, and the abrasion loss of about 0.022 g, when the composition containing the glass of 70 wt% is fired at 1050. These results are better than the properties of commercial clay tiles, due to easy melting and densification of glassy phase in the tiles.

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Characteristics of Machining Damage and Their Influence on Strength in Alumina Ceramics System

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.317-318.285 ◽

2006 ◽

Vol 317-318 ◽

pp. 285-288 ◽

Cited By ~ 1

Author(s):

Satoshi Tanaka ◽

Kazuyoshi Sato ◽

S. Yonetani ◽

Tsuyoshi Nakamura ◽

Keizo Uematsu

Keyword(s):

Grain Size ◽

Laser Fluorescence ◽

Machining Process ◽

Stored Energy ◽

Alumina Ceramics ◽

Pressing Method ◽

Grain Sizes ◽

Dry Pressing ◽

Confocal Scanning Laser ◽

Machining Damage

Machining damage and its influence on strength was examined for alumina ceramics with various grain sizes, which were prepared by dry-pressing method with spray-dried granules, followed by sintering at 1350-1550°C for 2-27 hours. Grain sizes of the sintered bodies were 1-6μm. After machining at the same grinding force, specimens were placed in an alcohol solution of fluorescent dye and dried. The fracture strength was measured by 4 point bending. The machining flaws in the specimens were observed with a confocal scanning laser fluorescence microscope. Machining flaws appeared continuous, wide and deep in the specimen with small grain size, and discontinuous with large size. On ground surfaces, intra-grain fracture appeared on the surface, whereas inter-grain fracture dominates. The continuous, wide and deep flaws were attributed to the dissipation of stored energy associated with the cracks propagation. The result suggested that the stored energy on the machining process increased with decreasing grain size. The strength of the specimen with 1 μm grain size reduced from 500MPa to 250 MPa with machining damage. The strength depended remarkably on the depth of the machining damage.

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Development of BaTiO3 Based X7R Wafers for Single-Layer Capacitors

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.69 ◽

2007 ◽

Vol 280-283 ◽

pp. 69-72

Author(s):

Zhengbo Yu ◽

Vladimir D. Krstić ◽

Jack Ng

Keyword(s):

Mechanical Properties ◽

Dielectric Constant ◽

Temperature Coefficient ◽

High Frequency ◽

Sintering Temperature ◽

Single Layer ◽

Dissipation Factor ◽

Cold Isostatic Pressing ◽

Dry Pressing

Research on the development and characterization of X7R BaTiO3 dielectric wafers for high frequency single-layer capacitors has been carried out. Commercial BaTiO3 powders were processed and optimized in dielectric constant (er), dissipation factor (DF) and temperature coefficient of capacitance (TCC). The results indicate a strong effect of sintering temperature on dielectric properties as well as on mechanical properties of the BaTiO3. It has been shown that the highest dielectric constant is achieved at high sintering temperatures (>1400°C) and lowest TCC at lower sintering temperatures (<1300°C). By optimizing fabrication process e.g. dry pressing, cold isostatic pressing, sintering, and machining such as grinding and lapping, BaTiO3 wafers of dielectric constant from 3400 to 3600, with a diameter approximately 50mm and thickness 150µm, have been manufactured successfully. The fabricated thin wafers exhibit the X7R capacitor characteristics of the dissipation factor (<3%) and temperature coefficient of capacitance (<±15%) in the temperature range of –55°C to 125°C.

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Electrical Characterization of Mullite Bodies Containing Al-Rich Anodizing Sludge

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.1726 ◽

2006 ◽

Vol 514-516 ◽

pp. 1726-1730 ◽

Cited By ~ 1

Author(s):

M.J. Ribeiro ◽

João Carlos de Castro Abrantes ◽

Joao A. Labrincha

Keyword(s):

Electrical Characterization ◽

Phase Evolution ◽

Insulating Materials ◽

Shaping Technique ◽

Treatment Processes ◽

Dry Pressing ◽

Ball Clay ◽

Percolation Limit ◽

Clay Kaolin

Al-rich sludge produced from industrial anodising and surface treatment processes had been tested in the fabrication of mullite-based materials, by using unidirectional dry pressing as shaping technique. Mixture with common natural silica and magnesium-containing materials, like ball clay, kaolin and diatomite were prepared in order to achieve interesting final fired refractory and/or electrical insulating materials. Microstructural changes upon sintering and crystalline phase evolution are detailed and their relationship with the electrical behaviour is also studied, by the use of impedance spectroscopy. Finally, different models were used to fit the experimental electrical resistivity values and to estimate the percolation limit of the bi-phase material.

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