1. Thermo-Mechanical Behaviour of LCC in Presence of Glassy Phase Containing Sintered Alumina Aggregate.

Manidip Jana, Debasis Bhattacharya, Rajesh Bahinipati and Swapan Kumar Das

Two types of low cement castable (LCC) coded as C1 and C2 were prepared utilizing 50wt% previously synthesized sintered alumina aggregate (HA1 and HA2), 25wt% calcined kaolin aggregate, 20wt% reactive alumina and 5wt% calcium aluminate cement (CAC). Physico and thermo-mechanical properties of both the castables heated at different temperatures were compared. The results indicated that the C2 castable showed higher density and cold crushing strength due to enhanced sintering in presence of glassy phase. In contrast, C1 castable exhibited higher thermo-mechanical properties due to aggregate purity. The deterioration in hot modulus of rupture (HMOR values 5.98 MPa for C1 and 5.10 MPa for C2) and refractoriness under load (RUL values 1620 for C1 and 1515°C for C2) in C2 is within the acceptable limit for many high temperature applications. The phase composition of 1500oC heated castables and densely packed microstructure with clusters of corundum grains (major) and rod like mullite crystals embedded in the matrix shown beneficial effect on their physico and thermo-mechanical properties.

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9. Optimization of Alumina Powder Preparation Conditions for Ceramic Membrane Support Sintering.

Xuewen Liu, Jingtang Zheng, Changhai Li, Mingbo Wu, Dongmei Jia and Yuejin Li

Alumina powder is an important raw material for ceramic membrane supports. This paper reports the optimization of the preparation conditions of Al₂O₃ powder used for sintering ceramic membrane support. The experimental results show that ball-to-powder ratios of 9:1 to 11:1 and grinding times of 9 h to 10 h are the optimal conditions. Ultrasonic wave may affect the agglomeration state of the powder but not the crystal type, particle size, and size distribution of the Al₂O₃. The powder-milled sample produced at the optimal wet ball grinding conditions can be directly sintered into a ceramic membrane support.

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17. The Formation of Yttrium Aluminium Monoclinic (Y4Al2O9) by Sol-Gel Synthesis at Low Heating Temperature.

Ikhwan M. K., Azis R.S., Hashim M., Holland D., Howes A.P., Zakaria A. and Hassan J

Y₄Al₂O₉ has been synthesized by means of the citrate-nitrate sol-gel combustion method using yttrium (III) nitrate and aluminium (III) nitrate. DTA/TG analysis, X-ray diffraction (XRD), FT-IR and ²⁷Al magic angle spinning nuclear magnetic resonance (MAS NMR) measurements were used to characterize the phase decomposition, weight loss of the sample, the crystal structure and phase formation of the Y₄Al₂O₉ material. XRD shows the Y₄Al₂O₉ starts to crystallize at low temperature, 700 °C, with an average particle size around 49 nm.

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25. Kinetics of Isothermal Dehydration of Gibbsitic Bauxite.

Ray D. and Parya T.K

The thermal dehydration kinetics of naturally occurring gibbsitic bauxite have been studied using a thermogravimetric method in static air under isothermal conditions. The bauxite sample was characterized by chemical analysis, differential thermal analysis, specific surface area, particle size distribution, X-ray diffraction and scanning electron microscopy. Kinetics of thermal dehydration were interpreted and correlated using the ICTAC recommended integral isoconversional method and the Guggenheim method. Both rate constants and activation energies at initial and final stages of isothermal dehydration of bauxite were evaluated by Guggenheim method while only activation energies by integral isoconversional method.

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36. Development of Young’s Modulus of the Green Alumina Porcelain Raw Mixture.

Štubňa I., Šín P., Trník A., Podoba R. and Vozár L

Young’s modulus of a green mixture (50 wt. % of kaolin, 25 wt. % of Al₂O₃, and 25 wt. % of feldspar) was measured during heating using a resonant method. It was found that the liberation of the physically bound water (20 °C – 250 °C) strengthens the sample and Young’s modulus increases 30 %. On further heating, Young’s modulus continuously decreases up to 700 °C when Young’s modulus begins to rise. Above 950 °C, a steep increase of Young’s modulus is caused by the solid-state sintering and a new structure created by the high-temperature reactions in metakaolinite. A dehydroxylation, which takes place in the range of 400 °C – 650 °C does not influence Young’s modulus.

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43. The Use of Synthetic Wollastonite in Wall Tile Glazes.

Taşçı E.

In this study the effect of wollastonite addition in standard proportion on the properties of opaque glazes composition was investigated. Addition of wollastonite also increased the whiteness of glazes composition according to reference glaze. Before the glaze studies, the synthetic wollastonite was produced with PCC (Precipitated Calcium Carbonate) and quartz mixture. Wollastonite minerals, used in ceramic glaze compositions, are imported into Turkey. Therefore, as an alternative to the imported wollastonite, the aim has been to produce synthetic wollastonite using the raw material, PCC (Precipitated Calcium Carbonate), which has various particle sizes and is obtained from Afyon, Turkey. With this objective, the effect of two different mineralizers (LiNO₃, Na₂NO₃) on the formation of wollastonite has been analyzed through experimental studies. Samples containing quartz, mineralizer and PCC have been prepared so as to obtain a mixture of CaO:SiO₂ with a 1:1 mole ratio. In the prescription of a single firing (1125°C) wall tile opaque glaze, synthetic wollastonite, produced with a temperature regime of 1150°C, has been added instead of the imported wollastonite used in ceramic factories. The synthetic wollastonite which is produced has been characterized using XRD, SEM and glaze tests of wall tile opaque glaze containing synthetic wollastonite. L*a*b values have been measured after a single firing (1125°C). As a result of the XRD analysis carried out on the synthetic wollastonite, it has been observed that XRD peak intensities are higher in comparison with that of imported wollastonite and in the wall tile opaque glazes; the whiteness value and surface smoothness have also increased.

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52. A Simple Method of Producing Hydroxyapatite and Tri Calcium Phosphate.

Gunduz O

Hydroxyapatite (HA) has been widely used as a biocompatible ceramic in biomedical engineering applications in the past few decades. This paper reports on the preparation of hydroxyapatite and triaclium-phosphate (TCP) from a coral source using a simple mechanochemical method. Coral materials are made of calcium carbonate in the form of aragonite. Coral source materials were assessed using thermogravimetric and differential thermal analysis (TG/DTA). The resulting HA and TCP powders obtained were without any impurities. At two different elevated temperatures (of 400 and 800 °C) the coral was converted to HA and TCP materials. Scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies were performed.

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59. Mass Gain in Fired Clay Ceramics.

Ceren Ince and Shahram Derogar

The paper aims to investigate the mass gain in fired clay ceramics following reheating in order to gain a better understanding of the underlying kinetics of the rehydroxylation reaction using advanced gravimetric analysis. The effects of temperature on the kinetics of mass gain in fired clay ceramic following reheating to 500 °C are investigated. Arrhenius plots are constructed at different temperatures and the activation energy of the chemical recombination reaction calculated. Following reheating at 500 °C, fired clay ceramics gain mass due to the chemical recombination of atmospheric moisture and hence mass gain occurs in two distinct steps that both are linear with (time)^1/4. Separating Step II data from Step I provides insight to the nature of the Step II reaction.

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68. The Use of Roof Tile Wastes in Stoneware Glazes.

Münevver ÇAKI, Selvin Yeşilay KAYA, Büşra GÜNHAN and Fazilet GÜNGÖR

In this study usability of roof tile waste, which emerges after production in a roof tile factory in Turkey- Eskisehir, as glaze raw material has been analyzed. Terracotta roof tile wastes’ chemical (XRF) and mineralogical (XRD), dilatometer and thermal microscopy analyses, grain size distribution, and color and melting characteristics at 1160°C have been determined. In the first stage, roof tile waste has been used with ulexite, which is a boron compound, in a binary glaze system; in the second stage however roof tile waste has taken place in transparent stoneware glaze recipe with varying rates from 40 % to 95 %. Following the glaze firings at 1160°C, it has been observed that matte and flossy glazed surfaces changing from brown to black have been formed.

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76. Densification Behavior and Mechanical Properties of Spark Plasma Sintered ZrC–SiC and ZrC–SiC–CNT Composites.

Sumbule Sagdic and Gultekin Goller

ZrC-SiC and ZrC-SiC-CNT composites containing 0-30 vol% SiC and 0.25-1 wt% CNT were prepared by spark plasma sintering at 1750-1850°C for 300 s under a pressure of 40 MPa. Fully dense ZrC based composites with a relative density of approximately 99% were obtained. The hardness of ZrC-SiC composites increased from 18.2 GPa to 20.6 GPa when the content of SiC increased from 10 to 30 vol% and the fracture toughness of ZrC increased from 3.3 to 5.5 MPa·m^1/2 with the addition of 30 vol% SiC. Additionally, mechanical properties of ZrC-SiC composites having 30 vol% SiC increased with 0.25 wt% CNT. However, further addition of CNT resulted in lower hardness values and there was not any considerable difference in fracture toughness values for ZrC-SiC-CNT composites. The highest values of hardness and fracture toughness were 21.6 GPa and 5.8 MPa·m^1/2which was about 75% better compared to monolithic ZrC, and achieved with the addition of 30 vol% SiC and 0.25 wt% CNT.

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83. A Review of Refractory Linings for Gasification Reactors.

Gunjan Sukul and Balaramakrishna P. V

The gasification process offers a clean, efficient, and flexible way to convert carbon-based materials into electricity, hydrogen, and other chemical products at elevated temperatures and pressures. There are several types of commercially available gasification reactors based on the feedstock and end-product requirement. In many of these gasifiers, the service life of refractory linings has been considered as a critical barrier to gasification system economics, reliability, and online availability. For realizing higher plant availability a standby gasifier arrangement is being incorporated in the process schemes. The refractory linings in these gasifiers are subjected to a severe operating environment and selection of appropriate refractory material along with proper installation is an important step which will enable extended periods of continuous, trouble-free gasifier operation. In this paper, the state-of-art refractory lining design for various types of gasifiers has been reviewed with emphasis on the criteria for selection based on specific process conditions.

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93. Effect of Binders and Distribution Coefficient on the Properties of High Alumina Castable.

Akhilesh K. Singh and Ritwik Sarkar

Two different binder system, namely high alumina cement and silica sol, were used in high alumina castables, with different particle size distributions (PSDs). Distribution coefficients of 0.23 and 0.29, as per Dinger and Funk model were used to vary the PSDs of the castables and obtained self flowing and vibrational consistency in the prepared castable composition respectively. The castables were processed conventionally and various properties were evaluated and compared after heat treatment at 110°C, 900°C and 1600°C. Relatively lower density and cold crushing strength values were obtained for the sol containing fired castables, due to the formation of mullite phase.

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99. Structure and Ionic Conductivity of Codoped Ceria for IT-SOFC Electrolytes.

Arie Hardian, Gyeong Man Choi, Veinardi Suendo, and Ismunandar

Doped ceria is believed as the promising candidate for IT-SOFC electrolyte. Codoped strategy can increase the conductivity of single doped ceria at lower operating temperature. The purposes of this research were to synthesize and characterize several codoped ceria Ce_1-x-yGd_xM_yO_2-γ, M = Er, Dy, or Nd and 0.0 ≤ x,y ≤ 0.1. Solid state method was used due to it is a simple and suitable method for pilot scale. For the same total dopant concentration, the correlation between cation mean radii and the lattice parameter followed the Vegard’s rule. The activation energies of codoped ceria were lower than 1 eV and most of codoped ceria showed conductivities higher than 10^-2 S.cm^-1 at intermediate temperature range (500-800 °C).

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110. Investigation of Dental ZrO2 Ceramic Nano-Composite Calcined by Spark Plasma Sintering Technique.

Li-Qiang Xu, Wan-Zhong Yin, Jun-Xia Gong, Tian Li, Hong-Chen Sun and Wen-Zhi Song

For the investigation of dental ZrO₂ ceramic nano-composite with spark plasma sintering (SPS) process technique, the ZrO₂ nanometer powder stabilized by Y₂O₃ and the Al₂O₃ nanometer powder were prepared in our laboratory, and further used for creating the ZrO₂ nano-composites. The pure ZrO₂ nanometer powder, as well as the mixture of 50 vol % the ZrO₂ nanometer powder and 50 vol % the Al₂O₃ nanometer powder were processed with ball milling, baked, and granulated with an isostatic cool pressing equipment. Calcination was performed with spark plasma sintering (SPS). The properties of as-sintered SPS samples were measured, and the patterns of XRD along with the imagines of SEM were obtained, and compared with previous research work.

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118. Cordierite Composites Using New Source of Waste; Sludge Cake From Aluminum Scrap and Dross Recycling Industry in Thailand.

Rattanavadi S., Punsukumtana L., Thavarungkul N. and Srisukhumbowornchai N

This study aim to synthesis cordierite composites using new source of alumina from waste. The first groups were Sludge cake from aluminum scrap and dross recycling industry (Aw.), the other groups were commercial grade Alumina and other raw materials were kaolin, ball clay and talcum. The raw materials were ground, pressed, and sintered between 1200°C to 1325°C for 1 hour. The samples were investigated by XRD and thermal shock resistance tested, firing shrinkage, water absorption, and COE. The developed of crystal were studies by SEM and EDS. The COE of the sample W. synthesized at 1325°C were 3.95 x 10^-6oC^-1 and the XRD analysis present that the main crystalline phase was cordierite. It can be concluded that the Aw. is a promising raw material and beneficial to Thai ceramics industry in terms of cost saving, competitiveness and environmental.

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126. Biaxial Strength Testing of Ceramics Using Square and Rectangular Specimens.

Cengiz Tahir Bodur

Biaxial strength testing of disc specimens of brittle materials, like ceramics, is widely used and standardized. If the available test specimens are in different shapes, like rectangular or square, a universal test method to measure the strength of ceramic materials is not available. In this work, test material, a SiC ceramic, in rectangular and square shapes was tested biaxially and the strength of the material was calculated by adapting the thin plate theory formulations from the literature. Biaxial strength values, calculated from measurements of the rectangular and square specimens were compared with the values of the standard biaxial tests of disc and also by the 3 and 4-point bend tests of the same SiC material. Biaxial strength values of the rectangular, square and disc specimens of SiC material are in good agreement and they are higher than 3 and 4-point strength values. Due to the good agreement between the biaxial strength values of disc, square and rectangular shape specimens, it can be concluded that the rectangular and square shape test pieces of ceramic materials can be biaxially tested to measure the strength values.

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135. Elaboration and characterization of multiphase composites obtained by reaction sintering of boehmite and zircon.

Belhouchet H., Makri H., Hamidouche M., Bouaouadja N., Garnier V. and Fantozzi G

In this work, different composites (zircon–mullite–zirconia, mullite–zircon–zirconia, mullite–zirconia, mullite–zirconia–alumina and alumina–mullite–zirconia) were developed by reaction sintering of boehmite (AlOOH) and zircon (ZrSiO₄). Several mixtures were used by varying the boehmite content from 10 to 90 wt. %. All powders were mixed and grounded by ball milling and then pressed in cylindrical form. Finally, the green specimens were sintered under normal conditions for 2 hours at temperatures between 1400 and 1600°C, with a heating rate of 5°C/min. The dilatometric curves reveal several microstructural transformations in these mixtures. The X-rays diffraction spectra revealed factors such as percentage of boehmite and zircon and the sintering temperature lead to the formation of several composites. The presence of the various phases was confirmed by micrographic observations.

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147. Ceramic Tile I: New Surface Formation Theory of Calibration: Impact Fracture.

Bin Xu Junpeng Shao and Jianjun Liu

In order to explore the surface formation mechanism of calibration ceramic tiles, a comprehensive experiment is designed to observe the formation process of the calibration ceramic tile. It is concluded from the experiment results that the surface of calibration ceramic tile is formed by impact fracture. Calibration is different from common grinding in the surface formation of ceramic tile.

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154. Comparative study of conversion of coral with orthophosphoric acid and ammonium dihydrogen phosphate to produce coralline hydroxyapatite and β-tricalcium phosphate.

Rabea-Naemi Rosa Cegla, Innocent J Macha, Besim Ben-Nissan, David Grossin, Greg Heness and Ren-Jei Chung

Biogenic materials like corals, which are readily available, could be used to produce bioceramic materials and address significant advantages due to their unique structures and chemical compositions that contain Mg and Sr. Many conversion processes has been in the past proposed. In this work, a comparison study between the conversion of coral with orthophosphoric acid and ammonium dihydrogen phosphate was conducted. The resultant structures and compositions were studied using XRD, ICP-MS, SEM and FTIR. The results show that with phosphoric acid the coral was converted into mainly monetite (92%). The ammonium dihydrogen phosphate converted approximately 76% of the coral to hydroxyapatite through solid state reactions. The two routes proved to be effective in producing bioceramic materials from corals under moderate conditions of temperature with a basic condition favouring the yield of hydroxyapatite.

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162. Ceramic Tiles II: Pore Effect on Surface Formation.

Bin Xu Junpeng Shao and Jianjun Liu

Previous investigations have shown that the presence of small defects in ceramic tile such as pores can lead to a drastic decrease in strength and surface gloss. This severely limits the strength of ceramic materials and the surface integrity of ceramic tile. Although pores in ceramic tile are usually seen as a disadvantage, it is possible that they are also an advantage. The purpose of this study is to demonstrate the advantages of pores in ceramic tile during the surface formation process. A series of experiments for calibrating and polishing tile were developed. It is concluded from the experiment results that pores aid the surface formation of ceramic tile by restraining the further development of cracks. The pores in the experimental ceramic tiles not only failed to lead to ceramic tile fracture, but they also presented advantages for the formation of ceramic tile.

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167. Review of Commercial Electronic Ceramic Materials in Australia; 50 years onwards.

Gerry Triani and Peter Bryant

This review paper will address the Australian history of electronic ceramic materials which were used primarily for their dielectric properties rather than their insulation properties. The history of these materials can be broken down into three main periods. The first period is that prior to 1950, when the electronic components industry was first set-up. The second period from approximately 1950 to 1975 involves the expansion and decline of the capacitor product lines and production capacity under the Ducon Condenser Company. The third period from approximately 1975 and continuing to the current day, involves the manufacture of piezoelectric components primarily through the Nucleus Ltd. and a group at Plessey Ducon and which was subsequently managed in turn by its successors, Plessey Australia, GEC Marconi, Thomson Marconi and the Thales Australia companies.

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176. Specimen Size Effects on the Compressive Strength of Porous, Open Cell Ceramics – Size Matters.

G. Heness, N. Booth and B. Ben-Nissan

This study investigates the effect of specimen volume on the compressive strength of open cell brittle ceramics. A series of unconfined and confined, compression tests on specimens ranging in volume and shape were carried out. Volume percent pore content, average pore size, average wall thickness and pore shape were determined. The crushing strength and apparent stiffness were measured and these results are correlated with the volume of material stressed. It was found that as the volume of this highly porous, cellular material increased the strength also increased. For a 99% decrease in volume, a 49% decrease in strength was found for cube specimens. End constraint and specimen confinement had no effect on the trends for the cube specimens.

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180. Characterization of Perovskite-Spinel Nanocomposites (BFO-ZFO) Ferrites Prepared by Chemical Route.

Soumya Mukherjee and Manoj Kumar Mitra

Equimolar proportion of perovskite-inverse spinel structure of Bismuth ferrite-Zinc ferrite nano composite is tried to prepare using chemical route. Thermal behaviour and crystallization formation of nano crystalline composites are analysed by Differential Scanning Calorimeter-Thermogravimetric Analyser. Annealing treatment in air is given at 500°C and 550°C for 2 hours to develop proper phase. Phases for nano crystalline composite materials formed are identified by X-ray Diffraction. The crystallite size is measured using Scherrer’s formula. Microstructural features of irregular polygon about 65nm and spherical particles about 50nm are revealed by Field Emission Scanning Electron Microscope (FESEM) and High resolution transmission electron microscope (HRTEM) while Electron diffraction X-ray spectroscopy (EDX) data supports composite composition by analyzing presence of elements within the entire matrix. High resolution HRTEM analysis shows the interplanar fringes of respective phases comprising synthesized nano composite material and its corresponding SAED pattern. Stretching and bending vibration values of Metal-Oxygen coordination bonds is obtained by Fourier transform infra-red spectroscopy (FTIR), verifying formation of perovskite spinel nano composite materials. Magnetic behaviour from M-H curve depicts supersaturated behaviour for the nanocomposite at room temperature.

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188. Instructions to Authors

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190. Authors Declaration

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