scholarly journals Synthesis and Colloidal Processing of Nanocrystalline (Y2O3-Stabilized) ZrO2 Powders by a Surface Free Energy Controlled Process

1996 ◽  
Vol 432 ◽  
Author(s):  
Detlef Burgard ◽  
Rüdiger Nass ◽  
Helmut Schmidt
Keyword(s):  
Free Energy ◽  
Tape Casting ◽  
Slip Casting ◽  
Particle Sizes ◽  
Colloidal Processing ◽  
Average Pore ◽  
Growth Technique ◽  
Casting Slip ◽  
Temperature And Pressure ◽  
Processing Techniques

AbstractUsing the controlled growth technique, nanocrystalline ZrO2 powders have een prepared from solution. By variation of the Y-content (0-8 mol %), redispersable monoclinic, tetragonal or cubic ZrO2 powders with particle sizes between 5 and 10 mn were obtained after crystallization at elevated temperature and pressure. Nanodisperse suspensions of the powders have been used for colloidal processing techniques such as tape casting, slip casting or extrusion. The resulting green bodies with densities of 55 % and average pore sizes of 5 nm could be sintered at temperatures below 1100 °C leading to monoclinic, tetragonal or cubic ZrO2 ceramics.

Determining the Lanthanum Chromite Zeta Potential in Aqueous Media

2010 ◽  
Vol 660-661 ◽  
pp. 1145-1150 ◽  
Author(s):  
Luiz Fernando Grespan Setz ◽  
Sonia Regina Homem de Mello-Castanho
Keyword(s):  
Fine Particles ◽  
Aqueous Media ◽  
Tape Casting ◽  
Slip Casting ◽  
Lanthanum Chromite ◽  
Zeta Potentials ◽  
Liquid Suspension ◽  
Present Complex ◽  
The Stability ◽  
Processing Techniques

Lanthanum Chromite may used as interconnect for SOFC’s applications due its particular intrinsic properties as stability in both oxidant and reducing environments and electrical conductivity. However to manufacture these devices that generally present complex shapes as grooved plates and fine pipes, they are necessary the use of the conformation techniques such as screen printing, slip casting, tape casting, extrusion moulding, etc. that are related with colloid processing. Independent of the processing techniques chosen the control of the suspension conditions is important to obtain reproducibility and homogeneous products as final result. In this sense, all contribution to understand the behaviour of the LaCrO3 fine particles in liquid suspension as the surface state using the Zeta’s Potential concepts may supplies information by the forecast of the behaviour during the shaped processing. The aqueous suspensions behaviour was studied utilizing doped lanthanum chromite powders, attained by combustion synthesis. The eletrophoretic mobility measurements of particles in suspension, prepared with the different conditioned powders were made. The electrolyte compositions as function of the pH varying from 2 to 12 were tested. The Zeta potentials and the stability conditions for stable suspensions prepared were determined. The viscosity curves are also appraised.

Exploring the Free Energy and Conformational Landscape of tRNA at High Temperature and Pressure

ChemPhysChem ◽  
2014 ◽  
Vol 16 (1) ◽  
pp. 138-146 ◽  
Author(s):  
Caroline Schuabb ◽  
Melanie Berghaus ◽  
Christopher Rosin ◽  
Roland Winter
Keyword(s):  
Free Energy ◽  
High Temperature ◽  
High Temperature And Pressure ◽  
Conformational Landscape ◽  
Temperature And Pressure

scholarly journals Application of reference-modified density functional theory: Temperature and pressure dependences of solvation free energy

2017 ◽  
Vol 39 (4) ◽  
pp. 202-217 ◽  
Author(s):  
Tomonari Sumi ◽  
Yutaka Maruyama ◽  
Ayori Mitsutake ◽  
Kenji Mochizuki ◽  
Kenichiro Koga
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Density Functional ◽  
Solvation Free Energy ◽  
Functional Theory ◽  
Temperature And Pressure

Residual stresses in Al2O3/Y-TZP Ceramic Laminates Fabricated by Tape and Slip Casting

2008 ◽  
Vol 571-572 ◽  
pp. 327-332 ◽  
Author(s):  
Jesus Ruiz-Hervias ◽  
Giovanni Bruno ◽  
Jonas Gurauskis ◽  
A.J. Sanchez-Herencia ◽  
C. Baudin
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Volume Fraction ◽  
Tape Casting ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Processing Route ◽  
Alumina Matrix ◽  
Stress Profiles

Residual stress profiles were measured by neutron diffraction in Al2O3/Y-TZP ceramic composites containing 5 and 40 vol.% Y-TZP fabricated by conventional slip casting and by a novel tape casting route. Residual stresses in the zirconia are tensile and increase as its volume fraction decreases. For the alumina matrix, residual stress is compressive and increases with the zirconia volume fraction. In the composite with 5 vol.% zirconia, the processing route does not have an influence on residual stresses. However, in the composite with 40 vol.% zirconia, residual stresses are different in the samples obtained by both processing routes.

Influence of the Type of Dispersant on the Properties of Casting Slips of Porcelains with Soda-Lime Glass

2006 ◽  
Vol 530-531 ◽  
pp. 449-455
Author(s):  
S.R. Bragança ◽  
R. Camaratta ◽  
A.C. Taborda ◽  
C.P. Bergmann
Keyword(s):  
Slip Casting ◽  
Soda Lime ◽  
Ceramic Materials ◽  
Partial Substitution ◽  
Attractive Alternative ◽  
Soda Lime Glass ◽  
Glass Waste ◽  
Different Types ◽  
Casting Slip ◽  
Extruded Products

The use of glass residues for the reduction of firing temperature of ceramic materials products has become an attractive alternative. For pressed or extruded products, such as tiles and bricks, the use of glass is sufficiently simple, since only milling and mixing to the industrial mass batch in partial substitution of conventional fluxes are necessary. However, in slip casting products, such as china and porcelains, the glass presence destabilizes the casting slip. This is the motivation of this work. Different types of dispersants and their influence on the properties of slips containing glass waste were evaluated. The experimental results showed that the use of conventional dispersant (sodium silicate) is not adequate. The stabilization of slips was possible only with organic dispersants. Therefore, the factors that determine the success or failure of dispersants were also analyzed.

Dolomite Decomposition to (Ca,Mg)O Solid Solutions: An X-Ray Diffraction Study.Part II.

1984 ◽  
Vol 39 (10) ◽  
pp. 981-985 ◽  
Author(s):  
G. Spinolo ◽  
U. Anselmi Tamburini
Keyword(s):  
Free Energy ◽  
Low Temperatures ◽  
Particle Sizes ◽  
Diffusional Process ◽  
X Ray Diffraction ◽  
High Iron Content ◽  
X Ray ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Low Pressures

Abstract The full decomposition of dolomites with low and high iron content at low temperatures and low pressures is discussed with reference to the free energy of mixing of the ternary system Ca. Fe, Mg/O. The actual products of the primary step are a couple of rock salt structured oxides close to the spinodal compositions and with very small particle sizes. A subsequent diffusional process can produce large crystallites with equilibrium compositions, but it is effective only when either a low-iron dolomite is used as starting material or higher temperatures are employed.

Effect of Sintering Temperature on the Mechanical Properties of Nanostructured Ceria-Zirconia Prepared by Colloidal Process

2015 ◽  
Vol 1125 ◽  
pp. 401-405
Author(s):  
Mohamed M. Aboras ◽  
Andanastuti Muchtar ◽  
Noor Faeizah Amat ◽  
Che Husna Azhari ◽  
Norziha Yahaya
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Cold Isostatic Pressing ◽  
Sintering Process ◽  
Colloidal Processing ◽  
Tooth Color ◽  
Biological Compatibility ◽  
Nanostructured Ceria

The demand for tetragonal zirconia as a dental restorative material has been increasing because of its excellent mechanical properties and resemblance to natural tooth color, as well as its excellent biological compatibility. Cerium oxide (CeO2) has been added to yttria-stabilized zirconia (Y-TZP), and studies have demonstrated that the stability of the tetragonal phase can be significantly improved. Y-TZP with 5wt% CeO2 as a second stabilizer was developed via colloidal process, followed by a suitable sintering process. According to the literature, the sintering process is the most crucial stage in ceramic processing to obtain the most homogeneous structure with high density and hardness. This study aims to investigate the effect of sintering temperature on the mechanical properties of nanostructured ceria–zirconia fabricated via colloidal processing and slip casting process with cold isostatic pressing (CIP). Twenty-five pellet specimens were prepared from ceria–zirconia with 20 nm particle size. CeO2 nanopowder was mixed with Y-TZP nanopowder via colloidal processing. The consolidation of the powder was done via slip casting followed by CIP. The samples were divided into five different sintering temperatures with. Results from FESEM, density and hardness analyses demonstrated statistically significant increase in density and hardness as the sintering temperature increased. The hardness increased from 4.65 GPa to 14.14 GPa, and the density increased from 4.70 to 5.97 (g/cm3) as the sintering temperature increased without changing the holding time. Sintering Ce-Y-TZP at 1600 °C produced samples with homogenous structures, high hardness (14.14 GPa), and full densification with 98% of the theoretical density.

Water Based Colloidal Processing of Ceramic Laminates

2007 ◽  
Vol 333 ◽  
pp. 39-48 ◽  
Author(s):  
Antonio Javier Sanchez-Herencia
Keyword(s):  
Processing Parameters ◽  
Colloidal Processing ◽  
Water Separation ◽  
Green Strength ◽  
Water Based ◽  
The Stability ◽  
Deflection Criteria ◽  
Joining Strength ◽  
Processing Techniques ◽  
Laminated Structures

Multilayered materials and coating are complex structures proposed among others to face the structural requirements of ceramics. The development of reinforcement mechanism by laminated structures can be due to deflection criteria or to the presence of residual stresses and requires of tailored laminates. These designs are characterized by the phases, thickness and distribution of the layers as well as the joining strength between them. In this sense water based colloidal processing techniques are used to fabricate layered structures by consolidating the layers from fluid dispersions of the powders in water. In these processing methods the phases presented in the final laminate are mainly given by the composition of the starting slurries while the changes in thickness and sharpness of the layers are controlled by acting on the processing parameters. The achievement of stable slurries is a shared step for all the colloidal processing techniques. In the water based slurries the stability will be dominated by the polar media, the surface behavior of the particles and the presence of dispersant additives to increase the repulsion between particles. The stable slurry ensures an effective milling and dispersion of the phases as well as high solid loadings, if required. Further processes associated to shaping and consolidation of the layers requires the incorporation of additives and-or water removal. The shaping methods based on aqueous slurries can be classified taking into account the process of solid-water separation. For each of those shaping methods, the nature and amount of the additives is different in order to get the optimum rheological behavior and green strength after drying. Depending on the thickness of layers and coatings as well as the shape and dimensions of the samples, the shaping method can be selected alone and combined with others.

Electric Discharge Machining of Conducting Ceramics - A Review

2021 ◽  
Vol 1019 ◽  
pp. 121-128
Author(s):  
T. G. Sachidhananda ◽  
V. Adake Chandrashekhar
Keyword(s):  
Electrical Discharge Machining ◽  
Ceramic Body ◽  
Tape Casting ◽  
Slip Casting ◽  
Pyrolytic Carbon ◽  
Machining Processes ◽  
Electric Discharge Machining ◽  
Complex Shapes ◽  
Assisting Electrode ◽  
Machining Characteristics

Electrical Discharge machining (EDM) is a nonconventional machining technique, which has been widely used to produce dies and mold. Harder Materials can be machined into complex shapes as long as they conduct electricity. Recent advances in the technologies brought the development of new engineering materials, which are hard to machine with traditional machining processes. Being one of these materials, ceramics possess some unique properties like piezoelectricity and tribological properties which are not found in metal and polymers. EDM is capable of machining these ceramics, given these materials have an adequately high electrical conductivity. Preparing conducting ceramics is pre-requisite for incorporating ceramics in EDM. Different techniques such as compaction, tape casting, extrusion, injection molding and slip casting are used form green ceramic body. These green bodies are subsequently sintered to obtain ceramic parts. Adding conducting elements in the ceramics while processing results in conducting ceramics. These additions increase hardness but fracture toughness of body is compromised. Ceramic parts can also be machined by using assisting electrode and pyrolytic carbon technique. This paper discusses the various methods of shaping conducting ceramics and its machining characteristics for EDM application

Exploring the influence of natural cosolvents on the free energy and conformational landscape of filamentous actin and microtubules

2018 ◽  
Vol 20 (45) ◽  
pp. 28400-28411 ◽  
Author(s):  
Paul Hendrik Schummel ◽  
Michel W. Jaworek ◽  
Christopher Rosin ◽  
Jessica Högg ◽  
Roland Winter
Keyword(s):  
Free Energy ◽  
Significant Influence ◽  
Filamentous Actin ◽  
Conformational Landscape ◽  
Temperature And Pressure

Natural osmolytes have a significant influence on the temperature- and pressure-dependent stability of filamentous actin and microtubules.

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