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  1. 76 Acta Physica Polonica A

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1
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Characteristics and Ceramic Properties of Turgutlu Clay

100%
Özkan İ.
Acta Physica Polonica A
|
2017
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vol. 131
|
issue 1
7-9
EN
The aim of this study is to characterize and determine the ceramic properties of the Turgutlu clay fired at various temperatures. For this purpose, the clay sample was first characterized by chemical analysis, X-ray diffraction, and plasticity measurements. The mineralogical composition of the Turgutlu clay was dominated by quartz, illite, mica, hematite, calcite, kaolinite, microcline, and smectite. The data obtained from plasticity tests indicated that the Turgutlu clay was very high plastic clay. To evaluate firing behaviors, pressed clay samples were fired separately at temperatures between 850 and 1100°C. Fired specimens were evaluated by water absorption, linear shrinkage, bulk density, flexural strength, X-ray diffraction, and scanning electron microscopy. Significant changes were observed such as an increase in the linear shrinkage and flexural strength together with a decrease in the water absorption above 1050°C. Based on the technological characteristics, the Turgutlu clay could be used in the manufacture of structural ceramics.
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Characterization of the Stones Used on Walls in Teos Hellenistic Period

100%
Polat Y., Tamsu Selli N.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 4
517-520
EN
Teos, one of the twelve Ion cities, is located in the of Sığacık neighborhood Seferihisar district, 60 km southwest of Izmir. The city, on the southern coast of the peninsula Erythrea and Izmir, is the bottleneck of the gulf sea of Samos. West of the city Erythrai (Ildırı), north Klazomenai (Urla), the south island of Samos is located in the southeast of the city of Colophon. The main city is on the black neck which is surrounded by filled gulf formerly named as Teos Gulf, now west of the gulf. In ancient times the city was surrounded by walls for defense purposes. The city walls provide important information about both political and economical structure of the city. Teos walls of Hellenistic Period around 65 hectares of area is surrounded by the city for about 4 km. In this study stone samples which were used in Hellenistic Period have been characterised. Stone samples have been analysed by the following methods: field observations (visual examinations), scanning electron microscope equipped with energy dispersive X-ray spectroscopy, X-ray diffraction and chemical analysis X-ray fluorescence methods. These methods provided us determination of stone properties.
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Characterisation of the Ancient City of Teos Western Necropolis Sherd Samples

100%
Polat R., Tunalı A.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 4
521-523
EN
Ancient city of Teos, one of the Ionian Religion Cities, is located in Sığacık district, Seferihisar Province in Izmir. The city was inhabited from Protogeometric period. The ancient city which has sheltered two harbors, due to its geographical position as a major trading center in the early emerges. Phokaia has been north of the city, Miletus has been south of the city, Samos and Khios Island have been in Ionian Cities. In this study, rescue excavations carried out by Izmir archaeological Museum in west and northwest of the city between 2013 and 2014. One of the necropolis is in the city as crow flies 1.1 km northwest, the other necropolis is located 1 km west of the city. This study will be dealt with the characterisation of clay and sherd samples which are obtained by necropolis. Samples from west and northwest of the necropolis of Teos City have been characterised by X-ray diffraction analyses and chemical analysis X-ray fluorescence methods.
4
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Effects of Alumina and White Fused Alumina Addition on Transparent Wall and Floor Tile Glazes

100%
Yildiz B., Ozturk Z., Kara A.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1090-1093
EN
In tile manufacturing, α-Al₂O₃ is the main type of alumina used in ceramic body and glaze formulations. This raw material acts as an opacifier in porcelain tile bodies and as a matting agent in glazes. White fused alumina (WFA) is produced by fusing calcined alumina in an electric arc furnace under carefully controlled conditions. It is usually employed in floor tile glazes in order to increase their abrasion resistance. The aim of this study was to establish a better understanding of how alumina and white fused alumina addition affects the thermal behavior and aesthetic properties of wall and floor tile transparent glazes. It was shown that both alumina and fused alumina increased the softening temperatures of the standard glaze composition. Corund was the main detected phase in tile glazes incorporated with fused alumina. This result suggested that white fused alumina did not react with glassy phase to form any other crystalline phases. This result can be attributed to higher refractoriness of white fused alumina. Presence of anorthite and gahnite phases was, on the other hand, observed in the glazes with alumina addition. It was further shown that alumina was more effective in increasing opacity and reducing glossiness compared to white fused alumina.
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Usage of Colemanite in Transparent Wall Tile Glazes

100%
Öztürk Z.
Acta Physica Polonica A
|
2015
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vol. 127
|
issue 4
1079-1082
EN
Boric oxide has an important place in glaze technology and is the second most important network-former after silica. Lower thermal expansion coefficient; higherchemical and mechanical durability; good glaze appearance are some of the benefits of boric oxide. In wall tile production; generally transparent frits with 1-7% boric oxide are used to obtain glossy transparent glaze. It can be said that boric acid is the fourth expensive raw material in frit production after zirconium, zinc oxide and potassium carbonate due to its high cost limits its usage in frit production. The aim of this study is to investigate colemanite (CaB₃O₄(OH)₃·H₂O) mineral usage in transparent frit production instead of using boric acid. To achieve this aim, four different frit mixtures Std, K.1, K.2 and K.3 with 0 wt.%, 3 wt.%, 6.5 wt.% and 11.5 wt.% colemanite content were prepared respectively. For comparison of the thermal behavior of frits, hot stage microscope was used. It was observed that, all of the samples prepared with colemanite have lower sintering and softening temperatures than the standard recipe because of its high earth alkaline oxide content. The obtained glazes were characterized by X-ray diffraction, dilatometer, Harcourt and Autoclave tests.
6
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Effect of Mechanical Activation on the Structural Properties of Mn-Doped Na_{0.5}Bi_{0.5}TiO_3 Ceramics

100%
Kırsever D., Özkan Toplan H.
Acta Physica Polonica A
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2016
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vol. 129
|
issue 4
610-612
EN
Piezoelectric ceramics (Na_{0.5}Bi_{0.5})TiO₃ + 0.5 mol.% Mn (Mn-NBT) have been synthesized by mechanical activation of mixed oxides BiO₂, Na₂CO₃, TiO₂ and MnO for 1 h at room temperature. Non-activated and activated Mn-NBT powders were characterized by using X-ray diffraction and scanning electron microscopy. Also, the mechanical activation-derived Mn-NBT powders were uniaxially pressed and all pellets were sintered at 1000°C and 1200°C for 2 h in air atmosphere. The microstructure and phase analysis of sintered pellets was investigated by using scanning electron microscopy and X-ray diffraction.
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The Effect of Different Fluxes on Thermal Behavior of Floor Tile Glazes

100%
Ozturk Z., Yildiz B.
Acta Physica Polonica A
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2015
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vol. 127
|
issue 4
1183-1185
EN
Nepheline-syenite is a fluxing agent used in sanitary ware, electrical porcelain and chinaware bodies, in order to reduce firing temperature and to increase the alkali level in the liquid glassy phase. Compared to pure feldspars, the advantages coming from the use of nepheline-syenite are: (i) the content of potassium and sodium is higher and (ii) the melting temperature is generally lower than that of potassium-feldspar, which always contains other phases, such as quartz, which shift the melting point to higher temperatures. The content of Al₂O₃ is high and the content of SiO₂ is lower in nepheline-syenite with respect to feldspars (considering that in feldspar Al₂O₃/SiO₂ is about 0.2, whereas in nepheline Al₂O₃/SiO₂ is 0.5). The aim of this study is to compare the influence of the nepheline-syenite and feldspars on the thermal behavior of the floor tile glazes. For this aim; several formulations were prepared with industrial raw materials. After applying the glazes on bodies; the compositions were fired in industrial floor tile kiln ( ≈1190°C, for 43 min). Thermal behaviors of glazes were measured by hot stage microscope and the crystalline phases were identified by X-ray diffraction. Color properties and glossiness were measured for comparing the aesthetic characteristics.
8
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Investigation of the Usage of Whitening Agents as an Alternative to Zircon in Opaque Frit Compositions

100%
Yildiz B., Ozturk Z.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1180-1182
EN
Zircon is the main opacifier in the ceramic sector, however its high cost limits its wide use and has led to the search of alternative materials. Nowadays, industrial whitening agents with different chemical formulas have started to be used in engobe, glaze and body compositions instead of zircon, to reduce raw material cost. Therefore, the purpose of this study is to investigate the possibility of usage of different industrial whitening agents as an alternative to zircon in opaque frit compositions. It was shown that, all of the studied whitening agents decreased the sintering and softening temperatures of the wall tile glazes. Although, alumina based whitening agents caused a glaze with transparent and boiling appearance, alumina with zircon and silica based whitening agents caused glazes with semi-opaque and glossy appearance. Even though none of the studied glazes has reached the standard whiteness indice, results suggest that alumina with zircon and silica based whitening agents could be a good candidate for zircon substitution in opaque frit compositions.
9
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Investigation of the Whitening Composition for the Porcelain Stoneware Tiles

100%
Selli N.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1202-1204
EN
A synthetic whitening composition is proposed as a whitening agent of porcelain tile body with a certain amount for the turning the body colour into whiteness. Active component used in the agent is zirconium silicate and this component is affected by the market speculation.This situation increases considerably the production costs. For these reasons an alternative whitening composition is required. The aim of the study is to prepare new whitening composition without zirconium silicate, with controlling crystalline phases in the porcelain stoneware tile, and to carry out characterization studies (such as XRD, SEM and EDX) and to correlate the whiteness value and the amount and type of crystalline phases in the porcelain tiles.
10
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Influence of Commercial Inert Glass Addition οn the Mechanical Properties οf Commercial Synthetic Hydroxyapatite

100%
Demirkol N., Nuzhet Oktar F., Sabri Kayali E.
Acta Physica Polonica A
|
2013
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vol. 123
|
issue 2
427-429
EN
In this study, microstructures and mechanical properties of commercial synthetic hydroxyapatite (CSHA)-commercial inert glass (CIG) composites were investigated. The goal of development of CSHA-CIG composite is to improve mechanical properties of hydroxyapatite. For this reason, CSHA powders were mixed with 5 and 10 wt% CIG separately. Pressed samples were sintered at the different temperatures in the range of 1000-1300°C. The physical and mechanical properties were determined by measuring density, compression strength, the Vickers microhardness. Structural characterization was carried out with X-ray diffraction and scanning electron microscopy studies. The experimental results were discussed to determine optimum amount of reinforcement material and the effect of sintering temperature on the microstructure and the mechanical properties of CSHA-CIG composites. The mechanical properties of composites decreased with increasing CIG content. The highest mechanical properties and the highest density were obtained in CSHA-5 wt%CIG composite sintered at 1300C.
11
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Investigation of the Basic Properties of Ceramic Proppants in Raw State Obtained by the Method of Mechanical Granulation

100%
Zarzycka D., Wisniewski P., Malek M., Szymanska J., Mizera J.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 4
552-555
EN
The investigation of fabricated ceramic materials, which can be used as proppants, is presented. Proppants are ceramic materials applied in hydraulic fracturing during extraction of shale gas. Solid slurry pumped with liquid into the deposit causes destruction of the rock structure. The role of proppants is to avoid closing of formed pores and as result enable gas migration from the deposit. Due to processing requirements and conditions in formations (high pressure and temperature), proppants should be characterized by proper physico-mechanical properties. The aim of this work was to elaborate the preparation method of ceramic materials, which can be used as proppants. In this paper results of properties studies of obtained proppants are presented. The influence of raw materials composition, especially the type of applied binder, was examined. Two types of green proppants obtained by the method of mechanical granulation without binder and with poly(vinyl alcohol) in amount of 5 wt% with respect to the powder were used. The properties: bulk density, roundness and sphericity coefficient, grain size and also structure and morphology of proppants was determined by the method of scanning electron microscopy with energy dispersive spectroscopy. The results indicate that composition of raw materials and type of binder have an important influence on the properties of obtained proppants in green state.
12
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Formation of Crystal Structure in Dielectric BaAl_2Si_2O_8-Based Materials Depending on Preparation Conditions

100%
Bliznyuk L., Klimza A., Petrochenko T., Fedotova V., Karwat C.
Acta Physica Polonica A
|
2014
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vol. 125
|
issue 6
1348-1351
EN
Crystal structure formation of BaAl_2Si_2O_8 known as polymorphic compound is investigated in present work depending on conditions of preparation. Characteristics of ceramics have been studied for different modifications of crystal structure. Additional technologic operations (grinding with following heat treatment) have been found to result in polymorphic transformation. Dielectric properties of BaAl_2Si_2O_8 ceramics have been studied for hexagonal, monoclinic crystal structure modifications as well as for that based on phase mixture. It has been shown that the sintering of ceramic material based on the monoclinic crystal structure modification of BaAl_2Si_2O_8 takes place in temperature diapason of 1300-1350°C. Sintering of material with the hexagonal crystal structure modification occurs in temperature diapason of 1450-1500°C. Ceramics materials based on compound BaAl_2Si_2O_8 are found to have low porosity, high Q-factor and dielectric characteristics, allowing use of these ceramic materials for production of resonators and other microwave equipments.
13
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Dielectric and Raman Studies of 0.935(Bi_{0.5}Na_{0.5}TiO₃)-0.065BaTiO₃ Lead Free Ceramics

100%
Lidjici H., Lagoun B., Khemakhem H.
Acta Physica Polonica A
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2016
|
vol. 130
|
issue 6
1431-1434
EN
The 0.935(Na_{0.5}Bi_{0.5})TiO₃-0.065BaTiO₃ lead free ceramic was synthesized by conventional solid state reaction technique. Sintering was done at 1200°C for 4 h in air atmosphere. Dielectric and Raman spectroscopic studies have been performed as a function of temperature from 25 to 450°C. The phase transitions from ferroelectric to antiferroelectric and from antiferroelectric to paraelectric order were observed through the dielectric measurements. Further support for the obtained results was drawn from the Raman spectroscopy measurements.
14
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The Carbothermal Reduction of Silica with Y₂O₃-MgO Powders

100%
Canikoğlu N.
Acta Physica Polonica A
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2017
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vol. 131
|
issue 1
162-164
EN
The aim of this study is to examine the effect of MgO and Y₂O₃ to the carbothermal reduction and nitridation of silica. The synthetic silica, MgO and Y₂O₃ powders were premixed (4wt% MgO-6% Y₂O₃, 5% MgO-5% Y₂O₃ and 6% MgO-4% Y₂O₃) in the starting reactants depending on the final powder composition. Carbon black was added to the silica (SiO₂) above the stoichiometric amount of oxygen (C/SiO₂ ratio of 3). The carbothermal reduction and nitridation process was carried out in a tube furnace at 1400°C, 1450°C, and 1475°C for 3 h under nitrogen gas atmosphere. The synthesized Si₃N₄ powder properties were examined by using X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectrosopy. In this study, MgO and Y₂O₃ powders dispersed in the final Si₃N₄ powder more homogeneously and thus formable and sinterable the starting mixing material is produced.
15
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Mechanical and Microstructural Properties of Sheep Hydroxyapatite (SHA)-Niobium Oxide Composites

100%
Demirkol N., Oktar F., Kayali E.
Acta Physica Polonica A
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2012
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vol. 121
|
issue 1
274-276
EN
The aim of this study is to produce and to investigate the mechanical and microstructural properties of composite materials made of hydroxyapatite, obtained from natural sheep bone and niobium oxide (5 and 10 wt%). Sheep hydroxyapatite (SHA) matrix was reinforced with 5 and 10 wt% of niobium (Nb) oxide powder. The calcinated SHA was ball milled separately with 5% and 10% niobium oxide for 4 h. The samples were subjected to sintering at different temperatures between 1000C and 1300°C. The mechanical properties were determined by measuring compression strength and Vickers microhardness (HV). X-ray diffraction and scanning electron microscopy studies were carried out to analyze the microstructure. With increasing sintering temperature, mechanical properties of composites increased. The SHA-composites with 10 wt% niobium oxide addition had better mechanical properties at all sintering temperatures. The highest mechanical properties were obtained in SHA-10 wt% niobium oxide composite sintered at 1300°C. Adding of niobium oxide to SHA could be a valuable method to produce rigid and high load carrying ability HA composite which is suitable for orthopedic applications.
16
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The Cordierite Formation in Mechanically Activated Talc-Kaoline-Alumina-Basalt-Quartz Ceramic System

100%
Kirsever D., Karakus N., Toplan N., Toplan H.
Acta Physica Polonica A
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2015
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vol. 127
|
issue 4
1042-1044
EN
The powder mixtures of Talc-Kaolinite-Alumina-Basalt-Quartz were mechanically activated in a planetary ball mill for 1 hour. The structural alterations and thermal behaviour of the powder mixture were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (TG-DTA). The results showed that the mechanical activation led to amorphisation and decreased the temperature of cordierite formation.
17
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Recycling of Secondary Aluminium Production Waste in Processing of Mullite Based Refractory Ceramics

100%
Kirsever D., Karabulut N., Toplan N., Toplan H.
Acta Physica Polonica A
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2015
|
vol. 127
|
issue 4
1035-1037
EN
This work describes the studies to reuse secondary aluminium production waste (SAPW) derived from aluminium casting processes in the fabrication of mullite-based refractory ceramics. SAPW was characterized by using particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF). Secondary aluminium production waste (SAPW), quartz and Grolleg kaolin were mixed stoichiometrically, according to chemical formula of mullite (3Al₂O₃·2SiO₂) by ball milling. Cylindrical samples were consolidated by uniaxial dry pressing and sintered at different temperatures (up to 1350°C). The phase and microstructural evolution, water absorption, bulk density, mechanical properties of sintered samples were investigated and refractory ceramics based on mullite were obtained.
18
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Comparative Study of Sb₂O₃ (Sb₂O₅) and Ta₂O₅ Doping Effects with TeO₂ on Electrical Properties of δ-Bi₂O₃

63%
Loubbidi L., Chagraoui A., Villain S., Bourja L., Orayech B., Ait Sidi Ahmed O., Moussaoui A., Tairi A.
Acta Physica Polonica A
|
2016
|
vol. 130
|
issue 4
862-865
EN
In this study, Sb₂O₃ (Sb₂O₅) and Ta₂O₅ are used as co-dopants with TeO₂ to stabilize the delta phase of bismuth oxide (δ -Bi₂O₃). Some compositions with formula (1-x) BiO_{1.5}-(x/4) Sb₂Te₂O₉ and (1-x) BiO_{1.5}-(x/4) Ta₂Te₂O₉ (x=0.1, 0.2, 0.3, 0.6, and 0.9) have been synthesized by solid state reaction at 850°C and characterized by powder X-ray diffraction. The Bi_{0.9}Sb_{0.05}Te_{0.05}O_{1.575}, Bi_{0.9}Ta_{0.05}Te_{0.05}O_{1.575} and Bi_{0.8}Ta_{0.1}Te_{0.1}O_{1.65} retain a cubic fluorite structure of δ -Bi₂O₃ phase. The electric properties were studied by impedance spectroscopy. All samples were evaluated by calculating conductivities and activation energies. Various impedance model including constant phase element and the Warburg impedances have been used to interpret the Nyquist representations of electrical analyses.
19
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The Spark Plasma Sintering of Silicon Carbide Ceramics Using Alumina

63%
Unlu M., Goller G., Yucel O., Sahin F.
Acta Physica Polonica A
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2014
|
vol. 125
|
issue 2
257-259
EN
SiC ceramics were fabricated by spark plasma sintering technique with the use of Al_2O_3 additive. The sintering process was carried out at three different temperatures in the range of 1700-1800C applying two different pressures 40 and 80 MPa under vacuum atmosphere. The effect of additive, different temperatures and pressures on densification behaviour, density, Vickers hardness, fracture toughness, and microstructure were examined. The hardness and fracture toughness of the samples were evaluated by the Vickers indentation technique. Microstructure of spark plasma sintered SiC samples were characterized by using scanning electron microscopy technique. The highest value of fracture toughness 5.9 ± 0.2 MPa m^{1/2} was achieved with the addition of 5 vol.% Al_2O_3.
20
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Molten Salt Synthesis of Conducting and Superconducting Ceramics

63%
Kolincio K., Gdula K., Mielewczyk A., Izdebski T., Gazda M.
Acta Physica Polonica A
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2010
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vol. 118
|
issue 2
326-327
EN
The functional properties of many interesting materials are the best if the materials are dense and have ordered or partially ordered microstructure. Obtaining such materials most often requires very time and energy consuming technologies, like high temperature and high pressure synthesis. In this work the applicability of the molten salt synthesis method, which is a simple and cheap technology, to the synthesis of the selected high temperature superconductors, ionic conductors and dielectric materials have been discussed.
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