scholarly journals Influence of the firing temperature on the dielectric properties of ceramics based on barium titanate

2021 ◽  
Vol 5 (3(61)) ◽  
pp. 10-13
Author(s):  
Georgiy Lisachuk ◽  
Ruslan Kryvobok ◽  
Artem Zakharov ◽  
Valentyna Voloshchuk ◽  
Mykyta Maistat ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Water Absorption ◽  
Firing Temperature ◽  
Open Porosity ◽  
Functional Materials ◽  
Ceramic Materials ◽  
Ceramic Technology ◽  
Pressing Pressure ◽  
Press Powder

The object of the research is the firing temperature of ceramic materials based on barium titanate. In laboratory conditions, barium titanate was synthesized from raw materials of barium carbonate and titanium dioxide using ceramic technology, taking into account the stoichiometric composition of the compound. In order to study the effect of the firing temperature on the properties of the ceramic material, three temperatures were selected: 1270, 1300, and 1350 °C. The physical properties of the samples (imaginary density, water absorption, open porosity) were determined by the method of hydrostatic weighing in water. The samples were saturated with water after their preliminary evacuation. The dielectric characteristics of the obtained materials were measured on an E7-8CLR automated device (Ukraine) at a frequency of 1 kHz. The structural and morphological features of ceramics based on synthesized barium titanate were investigated by direct scanning electron microscopy and X-ray phase analysis. On the basis of the complex of studies carried out, the technological parameters of the production of ceramics were selected. Thus, the duration of grinding at the first and second stages is 10 and 30 minutes; moisture content of the press powder – 8 %; pressing pressure – 20 MPa; temperature of the first firing – 1000 °С; temperature of the second firing – 1350 °C. The regularity of the change in the dielectric constant on the firing temperature of ceramics based on barium titanate was established. The investigated samples, obtained according to the given technological regime, are characterized by the following indicators: dielectric constant – 259.9; open porosity – 0.02 %; water absorption – 0.01 %; imaginary density – 5.45 g/cm3. The resulting material can be used to create composite ceramic materials that protect biological and technical objects from the effects of electromagnetic radiation, and can also be used to create new functional materials for space, aerospace, electronic engineering and medicine.  

scholarly journals Influence of Firing Temperature on Phase Composition and Color Properties of Ceramic Tile Bodies

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6380
Author(s):  
Kornelia Wiśniewska ◽  
Waldemar Pichór ◽  
Ewelina Kłosek-Wawrzyn
Keyword(s):  
Phase Composition ◽  
Flexural Strength ◽  
Water Absorption ◽  
Amorphous Phase ◽  
Firing Temperature ◽  
Open Porosity ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Total Water ◽  
Blue Shade

This study is focused on the behavior of the cream-firing clays from Opoczno region (Poland). The ceramic masses on which tests were carried out consisted of cream-firingBorkowice clay and dolomite in two different grain sizes as an additive that changes the color of ceramic materials. Test samples were prepared by plastic method and fired at range of 1100–1240 °C. Phase composition of theinvestigated materials was characterized by XRD method with quantitive analysis of the amorphous phase determined by the Retvield technique.Color properties of the surface of the obtained ceramic materials were determined in CIE-Lab color space. The phase composition of the obtained ceramics depends on the firing temperature. The color of the surface of the ceramic materials also depends on the firing temperature. There was a tendency to decrease the brightness, decrease the blue shade, and increase the yellow shade of the surface of materials with increasing the temperature. The conducted tests allowed to conclude that the color of ceramic materials depends on their phase composition. The most important role in the formation of color correspond to the amorphous phase, formed during the process. The lower content of the amorphous phase in the material allows to obtain brighter products with a lower proportion of yellow, and therefore closer to white. Moreover, following tests were carried out: total water absorption, total open porosity, linear shrinkage, and flexural strength. With increasing the temperature, total water absorption and total open porosity decrease, and total linear shrinkage increases due to the progressive sintering process. Flexural strength increases with the increase of the firing temperature for materials consisting of Borkowice clay. The addition of dolomite introduced new pores into the material, which resulted in an increase in flexural strength at lower firing temperatures and a decrease in flexural strength at higher firing temperatures.

scholarly journals Highly-refractory spinel-bonded aluminapericlase-carbonaceous ceramic materials

2018 ◽  
pp. 23-27
Author(s):  
Z. A. Babahanova ◽  
M. N. Aripova
Keyword(s):  
Crystal Structure ◽  
Water Absorption ◽  
Compression Strength ◽  
Open Porosity ◽  
Ceramic Materials ◽  
Ceramic Samples ◽  
Ultimate Compression Strength

The slag-resistant highly-refractory alumina-periclase carbonaceous ceramic materials were synthesized out of the Kazogneupor's electro-cast corundum, Zinel'bulaksk's (Uzbekistan) talc, and enriched graphite concentrate (Uzbekistan). The crystal structure of the materials is formed of corundum and spinel. The refractoriness of the ceramic samples is higher than 1800 °C, the density is 2520‒2880 kg/m3, the water absorption is 6,75‒11.71 %, open porosity is 16‒21 %, and the ultimate compression strength is 100‒120 MPa.Ill. 3. Ref. 9. Tab. 2.

scholarly journals DIELECTRIC BEHAVIOR OF NANO BARIUM TITANATE FILLED POLYMERIC COMPOSITES

2013 ◽  
Vol 22 ◽  
pp. 1-10 ◽  
Author(s):  
A. PRATAP ◽  
N. J. JOSHI ◽  
P. B. RAKSHIT ◽  
G. S. GREWAL ◽  
V. SHRINET
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Polymer Composites ◽  
Hydrothermal Process ◽  
Volume Resistivity ◽  
Polymeric Composites ◽  
Ceramic Materials ◽  
Dissipation Factor ◽  
Dielectric Behavior

Rapid growth of electronic industry requires development of new materials that combine the high dielectric constant intrinsic to ferroelectric ceramic materials with easy processing characteristics of polymers. Ceramic-polymeric composites possess interesting properties for a variety of electronic applications including passive electronic devices. In fact, polymer-ceramic materials have drawn lot attention for use in microelectronic packaging, because they can give higher performance with lower cost, size and weight. In this work, attempts are made to prepare ceramic polymer composites followed by characterization of dielectric properties. The Barium Titanate ceramic powders are synthesized using the hydrothermal process. Crystal structure and crystallite size of particles are determined using X-ray diffraction. Silane treatment is carried out on Barium Titanate powder to increase its compatibility with polymer, followed with preparation of ceramic polymer composites. Epoxy and polyvinyledene fluoride (PVDF) polymers are used as matrices for preparation of the composites. The proportion of nanopowder is varied from 60 to 90 wt%. Dielectric properties such as volume resistivity, dielectric constant, dissipation factor are evaluated. Results indicate that the dielectric constant and dissipation factor vary between 18 -140 and 0.01 to 0.09, respectively as the relative ratio of polymer and silane modified Barium Titanate is varied. Specifically, at 90 wt% of 0.1 wt% silane modified Barium Titanate, the highest dielectric constant of 140 along with dissipation factor of 0.07 is obtained in the epoxy based system.

Composition and Ceramic Characteristics of Cretaceous Clays from Morocco

2014 ◽  
Vol 92 ◽  
pp. 209-214 ◽  
Author(s):  
Chaouki Sadik ◽  
Abderrahman Albizane ◽  
Iz Eddine el Amrani
Keyword(s):  
Flexural Strength ◽  
Water Absorption ◽  
Production Process ◽  
Magnesium Oxide ◽  
Firing Temperature ◽  
Ceramic Materials ◽  
Technological Characteristics ◽  
The Relationship

Investigations were undertaken to assess the chemical and technological characteristics in clay products from the Cretaceous deposit (Moroccan Meseta), in order to use them in refractory products. We have focused mainly on this clay because of its high content of alumina, silica and magnesium oxide, which are very favorable for the synthesis of refractory and ceramic materials. That is why the study has used several techniques of analysis (FX, XRD, SEM and technological tests. The samples were dry pressed on clay bodies and sintered at temperatures ranging from 900 to 1200°C. The relationship between water absorption, shrinkage and flexural strength as a function of the firing temperature was examined in order to enhance the quality of the final products and to optimize the production process. The results revealed that these clays have qualities necessary for the manufacture of ceramic and refractory products.

EFFECT OF TWO-DIMENSIONAL MECHANICAL STRESS ON THE DIELECTRIC PROPERTIES OF POLED CERAMIC BARIUM TITANATE AND LEAD ZIRCONATE TITANATE

1961 ◽  
Vol 39 (5) ◽  
pp. 741-753 ◽  
Author(s):  
R. F. Brown
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Barium Titanate ◽  
Lead Zirconate Titanate ◽  
Ceramic Materials ◽  
Ferroelectric Ceramic ◽  
Lead Zirconate ◽  
Dielectric Behavior ◽  
Two Dimensional

Studies have been made of the dielectric behavior of several ferroelectric ceramic materials when a two-dimensional stress was applied normal to the axis of polarization. It has been shown that the dielectric constant decreases and the dielectric loss increases with increasing stress, part of the change being irreversible and part reversible. Upon application of stress to a sample, the dielectric constant did not change instantaneously but appeared to decrease linearly with the logarithm of time. Mechanisms are suggested for the observed effects.

scholarly journals Influence of forming pressure on frost resistance of ceramics

2021 ◽  
Vol 2 (1(58)) ◽  
pp. 15-20
Author(s):  
Іrіna Subota ◽  
Larysa Spasonova ◽  
Аnastasia Sholom
Keyword(s):  
Water Absorption ◽  
Frost Resistance ◽  
Raw Materials ◽  
Ceramic Materials ◽  
Raw Material ◽  
Pressing Pressure ◽  
Environmental Friendliness ◽  
Dry Pressing ◽  
Speed Up ◽  
Technological Methods

The object of research is low-melting clays of the Kyiv region (Ukraine). The work is devoted to the study of obtaining ceramic materials resistant to low temperatures. Frost resistance is one of the most important characteristics for regions in which ceramic materials are used with frequent temperature transitions through 0 °C. The production of frost-resistant ceramic wall materials is determined by the type of raw materials and technological production parameters. The main technological methods for increasing frost resistance are: the use of less dispersed clays; batch homogenization; formation of raw material without textural defects and prevention of cracks during drying and firing. The work shows that the existing methods for increasing frost resistance can be implemented by reducing water absorption due to the creation of a microporous structure with predominantly closed pores by increased pressure of a semi-dry method of formation. An increase in the pressing pressure leads to an increase in the number of contacts of the molecules of the ceramic mass at the stage of formation. Due to this, the strength of the molded samples at a pressing pressure of more than 30 MPa is higher compared to samples molded by the plastic method. It was also found that an increase in the pressing pressure makes it possible to speed up the drying process of ceramic products, reducing energy consumption for their production. Due to an increase in the pressing pressure to 50 MPa, the strength of samples obtained by semi-dry pressing is 55.4 MPa, while for samples during plastic formation it is 22.9 MPa. Water absorption, on the contrary, for dry pressing is 9.3 %, while for plastic pressing it is 12.2 % at a firing temperature of 1000 °C. It is shown that increasing the pressing pressure is an effective way to improve the quality of ceramic materials based on local low-plasticity clay raw materials. Saving natural and energy resources, developing new sources of raw materials and comprehensive improvement of products with environmental friendliness of production remain important today.

scholarly journals Optimisation of the Physical Properties of Rice Husk Ash in Ceramic Materials Using the Response Surface Methodology

2021 ◽  
Vol 49 (1) ◽  
pp. 23-30
Author(s):  
Asotah Wisdom ◽  
Udochukwu Mark ◽  
Elakhame Zeberu ◽  
Abraham Adeleke
Keyword(s):  
Response Surface Methodology ◽  
Specific Gravity ◽  
Physical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Firing Temperature ◽  
Rice Husk Ash ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Apparent Porosity

Optimisation of the physical properties of rice husk ash (RHA) in ceramic materials was carried out using Response Surface Methodology. The independent variables, namely the firing temperature and residue content, were statistically combined in a Central Composite Design with the effects on water absorption, linear shrinkage, bulk density, apparent porosity and apparent specific gravity determined. Physical and microstructural analyses were carried out to obtain information on the processes that occurred within the ceramic materials. The results obtained were analysed to determine the optimum physical properties of the ceramic materials within the range investigated. The residue content had a significant influence (at 95% confidence level) on the bulk density, water absorption, apparent porosity and apparent specific gravity but not on the linear shrinkage. The firing temperature had a more significant effect on the linear shrinkage than on the residue content, so that when elevated it contributed to an increase in linear shrinkage. The optimum residue content and firing temperature to enhance physical properties within the range investigated were 5.85% RHA and 1029.64°celsius, respectively. These optimal conditions are expected to produce a ceramic material with a bulk density, linear shrinkage, apparent porosity, water absorption and apparent specific gravity of 1.64 g/cm3, 0.29%, 0.29 g/cm3, 18.26% and 2.11, respectively with a composite desirability of 100%.

Resistance to Synthetic Seawater Aggression of Clay Ceramics Incorporated with an Ornamental Stone Residue

2014 ◽  
Vol 798-799 ◽  
pp. 269-274 ◽  
Author(s):  
Gustavo de Castro Xavier ◽  
Jonas Alexandre ◽  
Paulo César de Almeida Maia ◽  
Fernando Saboya Albuquerque ◽  
Leonardo Gonçalves Pedroti ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Standard Procedure ◽  
Degradation Process ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Synthetic Seawater ◽  
Internal Expansion ◽  
Ornamental Stone ◽  
Clay Ceramics ◽  
Chloride Salts

Clay ceramic materials exposed to a marine environment may be subjected to complete degradation due to the presence of chloride salts in the air. The exposition allows the chloride to penetrate in structural pores causing an internal expansion, which eventually split the ceramic apart. In open air, the solar radiation as well as the rain and wind contribute to accelerate the degradation process. In the present work the laboratory assisted degradation of clay ceramics incorporated with a granite residue from ornamental stone processing was evaluated by synthetic seawater aggression according to standard procedure. The amount of incorporated residues, up to 10 wt % and the ceramic firing temperature, up to 900°C, were variable conditions statistically analyzed by factorial planning. Degradation wetting-drying tests were conducted up to 6 months. The results showed that the linear shrinkage of the residue-free ceramics do not stabilize during the test period for any firing temperature. By contrast, the residue-incorporated ceramics tend to stabilize after 4 months. In addition, a decrease in water absorption and flexural strength was observed in same speciemens.

scholarly journals Mineralogical Characterization and Firing Temperature Delineation on Minoan Pottery, Focusing on the Application of Micro-Raman Spectroscopy

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2652-2664 ◽  
Author(s):  
E. Grammatikakis ◽  
Kyriakidis ◽  
D. Demadis ◽  
Cabeza Diaz ◽  
Leon-Reina
Keyword(s):  
Bronze Age ◽  
Firing Temperature ◽  
Raw Materials ◽  
Morphological Characteristics ◽  
Ceramic Technology ◽  
Phase Identification ◽  
Mineralogical Characterization ◽  
Analytical Protocol ◽  
Crucial Information ◽  
Analytical Tools

Ceramic objects in whole or in fragments usually account for the majority of findings in an archaeological excavation. Thus, through examination of the values these items bear, it is possible to extract important information regarding raw materials provenance and ceramic technology. For this purpose, either traditional examination protocols could be followed, focusing on the macroscopic/morphological characteristics of the ancient object, or more sophisticated physicochemical techniques are employed. Nevertheless, there are cases where, due to the uniqueness and the significance of an object of archaeological value, sampling is impossible. Then, the available analytical tools are extremely limited, especially when molecular information and mineral phase identification is required. In this context, the results acquired from a multiphase clay ceramic dated on Early Neopalatioal period ΜΜΙΙΙΑLMIA (1750 B.C.E.–1490 B.C.E.), from the Minoan Bronze Age site at Philioremos (Crete, Greece) through the application of Raman confocal spectroscopy, a nondestructive/ noninvasive method are reported. The spectroscopic results are confirmed through the application of Xray microdiffraction and scanning electron microscopy coupled with energy dispersive Xray spectrometry. Moreover, it is demonstrated how it is made possible through the application of microRaman (μRaman) spectroscopy to examine and collect crucial information from very small inclusions in the ceramic fabric. The aim of this approach is to develop an analytical protocol based on μRaman spectroscopy, for extracting firing temperature information from other ceramic finds (figurines) where due to their uniqueness sampling and analyses through other techniques is not possible. This information can lead to dating but also to firing kiln technology extrapolations that are very significant in archaeology.

Ceramic Technology for Solar Thermal Receivers

1983 ◽  
Vol 105 (1) ◽  
pp. 73-79
Author(s):  
A. A. Kudirka ◽  
R. H. Smoak
Keyword(s):  
Thermal Energy ◽  
Low Cost ◽  
Ceramic Materials ◽  
Ceramic Technology ◽  
Solar Thermal ◽  
Receiver Design ◽  
Solar Thermal Energy ◽  
Energy Applications ◽  
Temperature Capability ◽  
Solar Applications

Development of ceramic receiver technology for advanced solar thermal energy applications is being pursued in order to achieve significant reductions in energy cost and increase the potential application of solar thermal energy. Basically, structural ceramics are being seriously considered for solar applications because of their high temperature capability, their nonstrategic nature, and their potential for low cost. In this paper, candidate ceramic materials for solar receivers and their characteristics are described, potentially applicable fabrication and processing methods are discussed, and their applicability and promise for solar receivers is assessed. Receiver design requirements as well as system requirements for solar applications are reviewed. Promising areas of application of ceramic receivers in the near future are also discussed. Current ceramic receiver development status and plans are described, including one receiver which has been successfully tested at gas exit temperatures of up to 1425°C.

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