Showing papers in "Transactions of The Indian Ceramic Society in 2012"
TL;DR: The dye-sensitized solar cells (DSSCs) as mentioned in this paper can be considered to be electrochemical devices consisting of a photoanode which has a thick film of a wide band gap oxide semiconductor, typically coated on a transparent conductive oxide (TCO) glass substrate, with TiO2 being sensitized with adsorbed dyes that absorb visible light.
Abstract: The development of dye sensitized solar cells (DSSCs), which have derived inspiration from photosynthesis, has opened up exciting new possibilities and paradigms for producing solar photovoltaics possibly at lower cost. The dye-sensitized solar cells with moderate power conversion (∼10%) efficiencies can be manufactured under regular lab conditions without needing clean rooms or very specialized facilities. The entire processing need not involve even a single vapour deposition step. The DSSCs can be considered to be electrochemical devices consisting of (a) a photoanode which has a thick film of a wide band gap oxide semiconductor (like TiO2), typically coated on a transparent conductive oxide (TCO) glass substrate, with TiO2 being sensitized with adsorbed dyes that absorb visible light, (b) an electrolyte that establishes the internal electrical continuity between anode and counter electrode and mainly plays the role of regenerating the dye such that the photoexcitation, electron injection and current fl...
109 citations
TL;DR: Transparent ceramics, a new class of advanced functional materials, find diverse applications in strategic and civilian sectors owing to its unique combination of mechanical and transmission properties as discussed by the authors, have made it possible to tailor the microstructural, mechanical and optical property relationships in case of advanced transparent ceramic materials.
Abstract: Transparent ceramics, a new class of advanced functional materials, find diverse applications in strategic and civilian sectors owing to its unique combination of mechanical and transmission properties. Technological advancements in ceramic powder synthesis, shaping and sintering have made it possible to tailor the microstructural, mechanical and optical property relationships in case of advanced transparent ceramic materials. Transparent ceramic materials are classified broadly as visible, mid wave and long wave infrared regions. The transparent ceramic systems, which are explored currently, include transparent alumina (as polycrystalline submicron alumina and single crystal sapphire (Al2O3)), aluminium oxynitride (AlON), spinel (MgAl2O4) and zinc sulphide (ZnS) ceramics. This review summarizes the status of the development of these ceramics and a case study on transparent zinc sulphide samples developed by chemical vapour deposition (CVD) followed by hot isostatic pressing (HIP). Physicochemical, therma...
36 citations
TL;DR: Alumina plays a fundamental role in the preparation of structured catalysts, either in the pure form or doped with non-aluminium elements as mentioned in this paper, due to its unique properties, alumina can be present or constitute the structured support of the catalysts (monolithic honeycombs and open-cell foams), can be used as washcoat, a high surface area layer that gives the geometrical framework a suitable morphology to support and disperse the catalytically active phase, or can act as primer.
Abstract: Alumina plays a fundamental role in the preparation of structured catalysts, either in the pure form or doped with non-aluminium elements. Due to its unique properties, alumina can be present or constitute the structured support of the catalysts (monolithic honeycombs and open-cell foams), can be used as washcoat, a high surface area layer that gives the geometrical framework a suitable morphology to support and disperse the catalytically active phase, or can be used as primer, an intermediate layer between the geometrical support and the washcoat that acts as “glue” between the two layers. This topical review gives an overview on the most recent studies concerning the adoption of alumina for the preparation of structured catalysts. In particular, the fundamental role of alumina as washcoat is deepened. Among the different methods available to coat a structured support with an alumina porous layer, the focus is put on the slurry coating process. The efforts towards the comprehension of the phenomena occur...
16 citations
TL;DR: In this article, the gelation behavior of an acid deficient aluminium nitrate solution (NO3 −/AI3+ = 2.5) with hexamethylenetetramine and urea was investigated to develop a gelation field diagram.
Abstract: Preparation of alumina and aluminium-cerium oxide microspheres was carried out by internal gelation process. The gelation behaviour of an acid deficient aluminium nitrate solution (NO3 −/AI3+ = 2.5) with hexamethylenetetramine and urea was investigated to develop a gelation field diagram. However, cerous nitrate solution formed two phase mixture, thus its gelation field diagram could not be prepared. Further, using limited composition range, smooth, crack free Al2O3 and (Al Ce) mixed oxide microspheres were prepared. The size distribution analysis of these spheres implied that the size of spheres could be controlled by changing the molarity of aluminium. XRD pattern of opaque hard spheres confirmed the presence of θ-alumina phase while that of (Al Ce) mixed oxide spheres depicted that cerium oxide containing alumina could also be obtained. FTIR spectra of the spheres illustrated the stretching mode of tetrahedral and octahedral Al-O coordination and bending mode of cerium in (Al Ce) mixed oxide spheres. S...
15 citations
TL;DR: In this article, the synthesis of Li4SiO4 powder through solution combustion route using silica from rice husk ash (RHA) is demonstrated, and phase purity of the powder depends on metal to fuel ratio of the starting solution.
Abstract: The present report demonstrates synthesis of Li4SiO4 powder through solution combustion route using silica from rice husk ash (RHA). RHA is cheap agricultural waste and can be easily procured. It is found that phase pure Li4SiO4 powder can be prepared at 650°C. It is also observed that phase purity of the powder depends on metal to fuel ratio of the starting solution. Finally, microwave sintering is carried out to densify the synthesized Li4SiO4 to more than 80% of theoretical density at a temperature 1000°C.
14 citations
TL;DR: In this article, three batch compositions were prepared utilizing iron ore tailing in the range of 45-60 wt, clay 25-35 wt% and feldspar 15-20 wt%.
Abstract: In the present study, three batch compositions were prepared utilizing iron ore tailing in the range of 45-60 wt%, clay 25-35 wt% and feldspar 15-20 wt%. The compacts were heated in the temperature range of 1100o-1150oC. All the samples heated at 1150oC possess very high cold crushing strength (>150 MPa) and high flexural strength (>60 MPa) with less than 0.1% water absorption. Such high mechanical strength is beneficial for floor tiles to prevent impact damage. The phase evolution during heating of the mixture of iron ore tailing, clay and feldspar have been characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) studies with energy dispersive X-ray analysis (EDX) of selected samples.
12 citations
TL;DR: In this article, three nucleating agents were selected, i.e. ZrO2, TiO2 and P2O5, and two heat-treatment schedules were used.
Abstract: Blast furnace slag collected from Bhilai Steel Plant, Chattishgarh, India, was used to prepare glass-ceramics using different nucleating agents. The slag with nucleating agent was melted at 1475°C for 2 h for homogenization and moulded into rectangular bars followed by annealing at 700°C for 15 min. The crystallization temperature was shifted towards higher value in presence of nucleating agent. Three nucleating agents were selected, i.e. ZrO2, TiO2 and P2O5. Two heat-treatment schedules were used. A morphological change in microstructure was noticed with different nucleating oxides.
11 citations
TL;DR: In this article, a DC reactive magnetron sputtering process in a 99.998% reactive nitrogen atmosphere was used to prep titanium nitride thin films, and the sputtering pressure was varied to study its influence on the as-deposited films, using low (0.80 Pa), intermediate (3.40-5.33 Pa) and high (11.33) sputtering pressures.
Abstract: Titanium nitride thin films were prepared using DC reactive magnetron sputtering process in a 99.998% reactive nitrogen atmosphere. The sputtering pressure was varied to study its influence on the as-deposited films, using low (0.80 Pa), intermediate (3.40-5.33 Pa) and high (11.33 Pa) sputtering pressures. The deposited films possessed colour that ranged from dark blue, characteristic of oxygen-rich titanium nitride films, to reflective golden yellow, reminiscent of stoichiometric TiNx films. Studies on the optical and microstructural properties were carried out using UV-visible spectrophotometry, scanning electron microscopy (SEM) and X-ray diffractometry. Characterization results showed variation in the optical and structural properties of the film depending on the deposition sputtering pressure with relatively higher enhancement in the optical transmittance of up to 97.52% in the visible region for films deposited under high and intermediate sputtering pressure conditions. The deposition rate of the fi...
9 citations
TL;DR: SiCp/Al2O3 matrix composites were found to possess enhanced mechanical properties such as flexural strength, fracture toughness and wear resistance, all at an affordable cost of fabrication.
Abstract: SiCp/Al2O3 ceramic matrix composites were fabricated using DIrected Metal OXidation (DIMOX) process. Continuous oxidation of an Al-Si-Mg-Zn alloy with appropriate dopants along with a preform of SiC particulate has led to the formation of alumina matrix surrounding silicon carbide particulates. The fabricated composites were investigated for wear resistance on a pin-on-disc tribometer against gray cast iron. Wear surfaces were examined under scanning electron microscope in order to identify the wear mechanisms involved. SiCp/Al2O3 matrix composites were found to possess enhanced mechanical properties such as flexural strength, fracture toughness and wear resistance, all at an affordable cost of fabrication. The superior high temperature resistance of SiCp/Al2O3 based ceramics makes them suitable for tribological applications above room temperature or in high speed non-lubricated sliding.
7 citations
TL;DR: In this paper, the effects of sintering temperature and reoxidation conduction on the positive temperature coefficient of resistivity (PTCR) effect of chip type Ba1.005-xSmxTiO3 (BSMT) ceramics were investigated.
Abstract: The effects of sintering temperature and reoxidation conduction on the positive temperature coefficient of resistivity (PTCR) effect of chip type Ba1.005-xSmxTiO3 (BSMT) ceramics were investigated. The samples were reoxidized at 600°-800°C for 0-3 h in air after being sintered at 1200°-1280°C for 30 min in a reducing atmosphere. The results indicated that the reduced BSMT ceramics reoxidized at 800°C exhibited a pronounced resistivity jump. Moreover, the room temperature resistivity and resistivity jump of samples decreased with increasing sintering temperature of 1200°-1280°C. Furthermore, BSMT ceramics with 0.6 mol% Sm3+ reoxidized at 750°C for 3 h after sintering at 1200°C for 30 min exhibited a significant resistivity jump of 3.2 orders of magnitude, along with a relatively low room temperature resistivity of 661.4 Ω.cm. In addition, the activation energy of the samples obtained at different sintering temperatures was also investigated.
7 citations
TL;DR: In this paper, thin films constituted by nano-size TiO2 particles were prepared by spray pyrolysis aerosol, and the aerosol was generated ultrasonically, of titanium butoxide deposited on the substrate at 250° and 375°C temperature.
Abstract: Thin films constituted by nano-size TiO2 particles were prepared by spray pyrolysis aerosol. The aerosol was generated ultrasonically, of titanium butoxide deposited on the substrate at 250° and 375°C temperature. As-deposited films were annealed at 600°, 700°, 800°, 900° and 1000°C, in atmospheric conditions. Raman and glancing angle X-ray diffraction spectroscopy were set to analysis photocatalytic properties of the films. Transmission and morphology of the films were characterized by transmission and scanning electron microscopy, respectively. With increasing substrate and annealing temperature transformation occurred from anatase to rutile phase. Theoretical analysis of the experimental details was considered by focussing on symmetry modes of the phases that were changed when the phase transformation took place.
TL;DR: In this article, a single phase of lanthanum chromite (LaCrO3) was synthesized by two routes employing auto combustion and conventional solid state routes, and phase investigation of the prepared samples was carried out by powder X-ray diffraction techniques.
Abstract: Lanthanum chromite (LaCrO3) was synthesized by two routes employing auto combustion and conventional solid state routes. Phase investigation of the prepared samples was carried out by powder X-ray diffraction techniques, which confirmed the single phase formation. Rietveld analysis of lanthanum chromite exhibited the orthorhombic structure with space group Pnma at room temperature. Well crystalline single phase of lanthanum chromite was obtained by calcination of powder at 1200°C by solid state technique and at 1000°C by auto combustion method. SEM images of lanthanum chromite exhibited the microstructure of crystals and the nature of agglomeration among them for both synthesis processes. Frequency and temperature dependent conductivity of the two samples revealed that conduction behaviour is independent of the synthesis route. The magnitude of DC conductivity for solid state sample was found to increase by little amount. SEM morphology and structural modes of vibrations were studied employing SEM and FTI...
TL;DR: In this paper, different alkaline earth silicate glasses have been studied for chemical interaction with different interconnects (Crofer 22APU, ODS and steel) using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) in order to understand the mechanism of interface formations and their growth.
Abstract: In order to check the feasibility of various glasses as sealing materials, it is necessary to understand the crystallization kinetics, thermal and structural properties of glasses and their interactions with other components of SOFCs. In the present study, different alkaline earth silicate glasses have been studied for chemical interaction with different interconnects (Crofer 22APU, ODS and steel). These heat treated diffusion couple processes were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) in order to understand the mechanism of interface formations and their growth. No chromium rich zone could be seen along the interface after 750 h at 850°C heat treated diffusion couple indicating absence of any adverse reaction at the interface in these samples.
TL;DR: In this article, a sedimentation study of suspensions of nano kaolinite in aqueous solutions of polyvinyl alcohol (PVA) as well as in water has been conducted.
Abstract: A sedimentation study of suspensions of nano kaolinite in aqueous solutions of polyvinyl alcohol (PVA) as well as in water has been conducted. The results demonstrate that PVA can be used to control the stability of nano clay suspension with respect to sedimentation. The adsorption of PVA lowers the viscosity of system resulting in an increase of solid loading for the same viscosity level. The results indicate that solid volume fraction, polymer concentration, and polymer molecular weight can be adjusted to get desired rheological behaviour and sedimentation stability.
TL;DR: In this paper, a new black pigment for colouring porcelain tiles by calcination of hematite waste and natural manganese ore mixtures was investigated as a way to produce cost-effective pigment.
Abstract: In this study, development of a new black pigment for colouring porcelain tiles by calcination of hematite waste and natural manganese ore mixtures were investigated as a way to produce cost-effective pigment. It was found that by incorporating 10 wt% manganese ore (containing about 75 wt% MnO2) into hematite waste (containing about 97 wt% Fe2O3), a black pigment can be obtained. The black pigment predominantly contained hematite phase indicating that manganese was dissolved in hematite structure, changing the brown colour of hematite into black colour.
TL;DR: In this article, Li2O acts as a network modifier and modifies the glass structure, and optical absorption studies reveal that optical band gap decreases with Li 2O content whereas Urbach energy (ΔE) shows an increasing trend.
Abstract: Glasses with composition xLi2O-(50–x)Bi2O3-10ZnO-40B2O3 have been prepared by conventional melt quenching method. Density and molar volume decrease with increase in Li2O content. The IR and Raman studies indicate that these glasses are made up of [BiO3] [BiO6], [BO3] and [BO4] basic structural units. Li2O acts as a network modifier and modifies the glass structure. The optical absorption studies reveal that optical band gap decreases with Li2O content whereas Urbach energy (ΔE) shows an increasing trend. The metallization criterion is found to be in the range 0.368-0.386, indicating the suitability of these glasses for non-linear optical properties.
TL;DR: In this article, the optimum conditions for the preparation of high quality materials were investigated by studying the effects of clay minerals percentage, sintering time and temperature on the quality of newly prepared bricks.
Abstract: Clay deposits of the Segui formation (Jebel Stah of the Gafsa basin, Southwestern Tunisia) were used as natural material for brick manufacturing. Factors influencing the preparation procedure were optimized by an experimental design to find out the most propitious conditions for the preparation of bricks of high quality. The collected clay samples were characterized by various techniques, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) and pycnometry. The optimum conditions for the preparation of high quality materials were investigated by studying the effects of clay minerals percentage, sintering time and temperature. Then various tests including sintering shrinkage, water absorption and compressive strength of the newly prepared brick samples were evaluated to determine the optimum preparation conditions. Results showed that the optimized conditions were: 80% illite, 830°C sintering temperature and 2 h sintering time. The same results showed that brick shrinkage depended mainly on ...
TL;DR: In this paper, the authors measured the Activation Energy of crystallization (Ea) by Kissinger's model considering the shift in peak crystallization temperature (Tc ) at three different heating rates (10°, 15° and 20°C).
Abstract: Glasses with nominal composition (mol%) 34BaO-10Al2O3-17B2O3-34SiO2-(5-x)La2O3-xTiO2 (x = 0, 1, 2, 3, 4) were prepared by melt quenching technique. Activation energy of crystallization (Ea ) was calculated by Kissinger's model considering the shift in peak crystallization temperature (Tc ) at three different heating rates (10°, 15° and 20°C.min−1) in differential thermal analysis. Among the glasses studied, composition with x = 1 had the maximum Ea as a result of its slower crystallization rate. Thermal expansion coefficients of as prepared bulk glasses matched with that of Crofer 22APU alloy. Sandwich type seals were made with two Crofer plates at 990°C and their vacuum integrity was tested at room temperature. Cross-sectional interface of the seals was studied under scanning electron microscope with energy dispersive X-ray analysis. Very different morphology at metal to glass-ceramics interface was observed with varying TiO2 concentration. Microstructure at the interface of the seal with x = 1 glass had...
TL;DR: In this paper, the role of Al2O3 in the network of potassium borate glasses, aluminium oxide has been added at the expense of B 2 O 3 keeping the amount of alkali same.
Abstract: The changes in Raman spectra of alkali borate glasses with and without Al2O3 under high dose of gamma irradiation have been reported. Glasses with composition xK2O.yAl2O3.(1–x–y)B2O3 (x = 20 or 30 mol%; y = 0, 10 or 15 mol%), have been prepared by melt-quenching technique. In order to investigate the role of Al2O3 in the network of potassium borate glasses, aluminium oxide has been added at the expense of B2O3 keeping the amount of alkali same. Gamma irradiation has been performed at a dose rate of 573 Gy.h–1 with total absorbed dose of 50 KGy. Samples were characterized before and immediately after irradiation by Raman spectrophotometer. The experimental results clearly indicate a significant change in the structure of borate glass matrix after irradiation, and the dependence of irradiation effects on composition of alkali as well as on aluminium oxide content.
TL;DR: Some effects induced by laser treatment in GeS2 glasses, glass-ceramics and selected chalcogenide crystals are presented in this article, where thermal treatment of glasses or introducing controlled disorder in crystal lattice give the opportunity to make the desired changes in the optical and electrical properties of materials.
Abstract: Some effects induced by laser treatment in GeS2 glasses, glass-ceramics and selected chalcogenide crystals are presented. We show that thermal treatment of glasses or introducing controlled disorder in crystal lattice give the opportunity to make the desired changes in the optical and electrical properties of materials. Irradiation by CW and pulsed lasers can significantly change the absorbance and birefringence in the 400-800 nm spectral range. We have observed and measured changes of absorption and refractive index, and investigated relaxation process after switching off the irradiation. Chalcogenide crystals were promising for use in optically operated devices through their photoconductivity and efficient frequency doubling. Different possible mechanisms responsible for the effects are discussed.
TL;DR: In this paper, it is inferred from 29Si NMR and XRD that glass-ceramics have high crystallinity and during crystallization initially Sr2ZnSi2O7 crystalline phase is formed and later SrSiO3 is crystallized.
Abstract: Glass having composition 40SrO-10ZnO-40SiO2-2B2O3-2Al2O3-2TiO2-2Cr2O3-2Y2O3 (mol%) was prepared by melt-quench technique and converted into glass-ceramics by controlled crystallization. Formed crystalline phases in glass-ceramics were identified using powder XRD. MAS-NMR spectroscopy shows the presence of mainly Q1 and Q2 silicate structural units and BO3 structural units of boron in the glass network. It is inferred from 29Si NMR and XRD that glass-ceramics have high crystallinity and during crystallization initially Sr2ZnSi2O7 crystalline phase is formed and later SrSiO3 crystalline phase is crystallized. 11B and 27Al MAS-NMR of glass-ceramics depict an increase in the BO4 and AlO4 structural units with the crystallization. In accordance with XRD, NMR results also suggest the formation of solid solution of Sr2ZnSi2O7 phase with substitution of Zn/Si tetrahedral sites with B/Al.
TL;DR: In this article, a polymer based nanocomposite coatings using polystyrene (PS) as the matrix and titania nanopowders as the dispersed phase is presented.
Abstract: Recently, there has been a great demand for hydrophobic (contact angle >90°) and super-hydrophobic surfaces (contact angle >150°) in industry for a variety of applications due to their easy to clean nature. In the present study efforts have been made to prepare hydrophobic polymer nanocomposite coatings containing titania nanoparticles. Titanium dioxide (TiO2) powders have been prepared by hydrothermal and co-precipitation methods and have been characterized by X-ray diffractometry, field emission scanning electron microcopy (FESEM) and Raman spectroscopy. The Raman and XRD studies confirm the presence of anatase titania for the hydrothermal synthesized and commercial titania powders. Titania derived from precipitation technique contains 68% rutile titania. Polymer based nanocomposite coatings have been prepared using polystyrene (PS) as the matrix and titania nanopowders as the dispersed phase. The obtained coatings have been characterized for contact angle and microstructure. Of the three sources of TiO...
TL;DR: In this article, a glass with 2 mol% P2O5 composition was used to construct Sandwich type geometry seals and these seals showed good bonding/adhesion of the glass with Crofer 22 APU.
Abstract: Glasses having compositions (mol%) (42–x)SiO2-39SrO-10B2O3-9ZnO-xP2O5 (SSBZP) where, x = 0, 1, 2, 3, 4 were prepared by melt-quench technique. Prepared glasses were characterized for density, thermo-mechanical properties and bonding behaviour with Crofer 22 APU alloy. Thermal expansion coefficient (TEC) values were found to be in the range of 9.7-11.1 × 10–6/°C (30°-600°C) which matches with TEC of Crofer 22 APU. Sandwich type geometry seals were prepared using glasses with 2 mol% P2O5. These seals showed good bonding/adhesion of the glass with Crofer 22 APU. Elemental line scans recorded using energy dispersive X-ray (EDS) indicated that interdiffusion of Fe, Cr and Si across interface is responsible for good bonding with Crofer 22 APU. However, in the present glasses, the effect of P2O5 incorporation on thermo-physical properties is insignificant.
TL;DR: In this article, the minimum grain size for different metallic glasses was calculated by considering a simple thermodynamic relation that suggests a general thermodynamic lower limit of grain size in polycrystalline materials.
Abstract: Polycrystalline materials with nanometer sized grains, termed nanocrystalline materials, can be formed by crystallizing completely amorphous solids under proper heat treatment conditions termed as ‘annealing’. Experimentally it is found that the smallest grain size is obtained when the glasses are annealed at a crystallization temperature which is nearly half of the melting temperature in metallic glasses. At this temperature the Gibbs free energy difference between the amorphous and crystalline state is maximum. However, in case of bulk metallic glasses (BMG), the maximum in Gibbs free energy, ΔG, is observed to fall below Tm /2, because the Kauzamann temperature (TK ), at which ΔG is maximum falls below Tm /2. Therefore, annealing BMG's at temperatures close to their TK is likely to lead to the smallest grain size. In this paper, we have calculated the minimum grain size for different metallic glasses by considering a simple thermodynamic relation that suggests a general thermodynamic lower limit of gra...
TL;DR: In this article, the composites were heat treated at 1000° and 1400°C in inert atmosphere and the microstructure of carbon-fly ash-ceramic composites was studied using SEM and optical microscopy.
Abstract: Carbon-fly ash-ceramic composites were developed by powder metallurgical route with phenolic resin and calcined petroleum coke as carbon precursor, and fly ash, silicon carbide, boron carbide, as reinforcements. The composites were heat treated at 1000° and 1400°C in inert atmosphere. Weight loss and volume shrinkage at 1000° and 1400°C were found to depend on the amount of phenolic resin used. The microstructure of the composites heat treated at these temperatures was studied using SEM and optical microscopy. The filler particles were found to be well distributed and bonded with the matrix. The porosity was found to increase with higher amount of fly ash. The structural changes in composites were also studied using XRD. The compressive strength and hardness of the carbon-fly ash-ceramic composites increased with incorporation of silicon carbide. The coefficient of friction was found to decrease with addition of higher amount of fly ash due to increased porosity but increase with increased amount of silic...
TL;DR: In this paper, the modification of mesoscopic structure under different sintering conditions has been investigated using neutron scattering techniques and scanning electron microscopy, and X-ray diffraction confirmed the purity of silica by comparing the diffraction pattern from pure silica.
Abstract: A porous ceramics is obtained using rice husk as the source of silica. The modification of mesoscopic structure under different sintering conditions has been investigated using neutron scattering techniques and scanning electron microscopy. X-ray diffraction confirmed the purity of silica by comparing the diffraction pattern from pure silica. Thermogravimetry data show that a phase transition occurs at 750°C. X-ray data confirms that sodium calcium silicate is formed after the latter transition. Small angle neutron scattering measurements reveal the presence of nanopores of two distinct size ranges; viz. 162 and 30 nm. Porosity of the compact by bulk density measurement has been found to be ∼50%.
TL;DR: In this article, a dry processing technique for saving energy and reducing cost is presented, the approach is based on dust collecting system with the conventional grinding edge technique and the dust collection system was based on external filtration style.
Abstract: This paper presents a dry processing technique for saving energy and reducing cost and the approach is based on dust collecting system with the conventional grinding edge technique. Dust collecting system is based on external filtration style. The ceramic tiles could be packed and stored immediately after processing without further drying. Experiment of dry processing system is investigated to evaluate the efficiency of saving energy. In the case of dust recovery and reutilization, ceramic factories have developed some new kinds of process to create new products by directly reusing the dusts.
TL;DR: In this paper, the guiding properties of an optical fiber with metal nano-particle embedded in the core region are investigated and experimental verifications are performed. But, the results are limited to the case of a single waveguide.
Abstract: In optical fiber network demand for high bandwidth is ever increasing and to satisfy the requirements dispersion related phenomena limit its potential. In this respect recent ventures are based on the use of noble metal nano-particles in the guiding structure to minimize the dispersion effect. Much work has been carried out to characterize slab waveguide where metal nano-particles are embedded in the guiding layer. However, the guiding phenomena of an optical fiber with metal nano-particle embedded in the core region and experimental verifications are yet to be explored.
TL;DR: In this paper, the authors present the investigations of kinetics of operational parameters, effect on properties and structure of powder mica, etc. The mica sample was subjected to mechanical activation in ultra-centrifugal mechanoactivator with a peripheral comminution path.
Abstract: Mechanical activation of mica is a great technological and technical problem because of their specific crystallochemical structure. This is dependent upon the type of equipment used and the type of disintegration process. The paper presents the investigations of kinetics of operational parameters, effect on properties and structure of powder mica, etc. The mica sample was subjected to mechanical activation in ultra-centrifugal mechanoactivator with a peripheral comminution path. During the investigation, some operating parameters, viz. number of rotor revolutions (rpm), sieve mesh size (µm) and current intensity (A), and some technological parameters, viz. time of mechanical activation, t (min), circumferential rotor speed, v (m.s−1), capacity of ultra-centrifugal mechanoactivator, Q (kg.h−1) and specific energy consumption, W e (kWh.t−1) were monitored. Analyzing the results it can be concluded that the rate of mechanical activation of mica was increased with the increasing load and rotor revolution of u...
TL;DR: In this paper, Li2O was investigated using DTA, XRD and SEM methods, and a surface crystallization was dominant for all the compositions studied according to DTA data.
Abstract: The crystallization process of Li2O.2SiO2-BaO.2SiO2 glasses was investigated using DTA, XRD and SEM methods. The incorporation of P2O5 did not result in volume crystallization; a surface crystallization was dominant for all the compositions studied according to DTA data. Lithium disilicate, barium disilicate and different forms of SiO2 were the identified phases after two-stage heat treatment. The spherulitic morphology was observed by SEM after primary crystallization temperature. After the crystallization of barium disilicate phase, the spherulitic morphology disappeared and massive polycrystalline microstructures were formed.