Showing papers in "Transactions of The Indian Ceramic Society in 1994"
TL;DR: For investigating the complex crystallochemical character of garnets occurring in multiply metamorphosed rock sequence of upper amphibolite-granulite facies, infrared spectroscopy has been found to offer some valuable clues as to the presence of OH-bands, unexpected in high P-T mineral phases as mentioned in this paper.
Abstract: For investigating the complex crystallochemical character of garnets occurring in multiply metamorphosed rock sequence of upper amphibolite-granulite facies, infrared spectroscopy has been found to offer some valuable clues as to the presence of OH-bands, unexpected in high P-T mineral phases The investigation has been supplemented by EPMA (electron probe microanalysis) and X-ray diffraction method IR studies of seven garnets from different areas of the Sittampundi (Tamil Nadu) metamorphic terrains reveal the presence of OH stretching components (around 3600 cm−1) A linear decrease in wavenumbers of IR bands in the 1000-450 cm−1 region is observed to be related with changes of cell-edges
3 citations
TL;DR: In this paper, the physicochemical and mineralogical characteristics of china clay waste from a washing plant in Kachchh district in Gujarat State were studied with the object of determining its suitability in the manufacture of low cost industrial ceramic items like tower packing materials and low tension insulators.
Abstract: Physico-chemical and mineralogical characteristics of “china clay waste” from a china clay washing plant in Kachchh district in Gujarat State were studied with the object of determining its suitability in the manufacture of low cost industrial ceramic items like tower packing materials and low tension insulators. The results showed that the “china clay waste” was essentially a mixture of kaolin and quartz associated with impurities like haematite, rutile, orthoclase, albite, calcite etc. The study also revealed that the material could be used even up to 50 wt % in complete replacements of both china clay and quartz in the stoneware composition for the development of tower packing materials and low tension insulators. The products developed also conformed to the respective BIS Specifications as required for commercial utilization.
3 citations
TL;DR: In this article, the authors reported performance data of periclase spinel bricks in a large capacity kiln reveal that apart from minor problems, the changeover from mag-chrome bricks to these bricks can be carried out successfully.
Abstract: As the modification in the clinkerization technology has been a continuous process over the years, the trend of refractory application in Cement Rotary Kiln (CRK) system has also undergone a considerable change. The fireclay/alumino-silicate bricks, high alumina bricks of different grades and conventional castables have been replaced by aluminous bricks with specific characteristics, e.g. coating repellent type, high strength insulating bricks, basic bricks of different types including dolomite, silicon carbide bricks and special castables with low cement, ultra-low cement and no cement along with new anchoring system to optimize the lining life.The recently reported performance data of periclase spinel bricks in a large capacity kiln reveal that apart from minor problems, the changeover from mag-chrome bricks to these bricks can be carried out successfully. However, the result achieved cannot be generalized as these can be influenced by kiln system, kiln feed and fuel parameters etc. The magnesia spineli...
3 citations
TL;DR: In this article, an improved pendulum type impact apparatus has been described for determining single and repeated impact strength of hard porcelain, and a definite fatigue behaviour has been demonstrated for specimens of a hard porcellain with progressive endurance at lower stress regimes.
Abstract: Ceramics are often put to applications where they are subjected to cyclic stresses frequently involving sudden loading. Thus, in the design of such materials there is growing concern about their response to repeated impact behaviour. In the present work, an improved pendulum type impact apparatus has been described for determining single and repeated impact strength. A definite fatigue behaviour has been demonstrated for specimens of a hard porcelain with progressive endurance at lower stress regimes. Endurance limit beyond 2 × 104 cycles was about 24.12% of the single impact breaking strength. Fatigue resistance parameter of the material was 5.52. Microstructural evidence showed that the fatigue crack path was mainly transgranular, controlled by porosity. Effect of cumulative residual stress is suggested to explain the fatigue behaviour of the porcelain.
2 citations
TL;DR: The massive expansion of glass industry in India, especially sheet glass industry over the last 15 years has, of necessity, led to a tremendous growth in the demand for silica sand as mentioned in this paper.
Abstract: The massive expansion of glass industry in India, especially sheet glass industry over the last 15 years has, of necessity, led to a tremendous growth in the demand for silica sand. Reserves of sup...
2 citations
TL;DR: In this paper, a software on IBM PC compatible system has been developed to take care of all the computations concerned and to draw the wind rose and equipollution rose from the base data.
Abstract: The area of the present study covers the glass industries at Firozabad, the glass town, which lies in the pollution sensitive area of Taj trapezium. The objective is to estimate the dispersion of stack emitted particulate matters in different wind-flow conditions (viz. low, average and high turbulent conditions or on calm conditions). Seasonal and meteoro-logical effects on dispersion and the spatial distribution of ground level concentrations were interpreted on the basis of Bosanquet Model of dispersion. A software on IBM PC compatible system has been developed to take care of all the computations concerned and to draw the wind rose and equipollution rose from the base data.
2 citations
TL;DR: In this article, some fluoride opal glass surfaces when exposed to the normal atmosphere selectively adsorb carbon dioxide and convert it to an organic compound, identified to be sodium formate.
Abstract: Some fluoride opal glass surfaces when exposed to the normal atmosphere selectively adsorb carbon dioxide and convert it to an organic compound. The organic compound was characterized and identified to be sodium formate. Probable reactions leading to the formation of the compound are proposed. These reactions have possible implications in the development of environmentally benign processes for synthesis of organic chemicals.
1 citations
TL;DR: In this paper, the possibility of formation of fine fused alumina grains with MgO in the form of magnesio-aluminate hydrate (MAH) was explored.
Abstract: Excessive firing shrinkage and secondary re-crystallization cannot be controlled if alumina powder produced from Bayer's process is exclusively used to develop dense alumina body. High alumina bodies having low firing shrinkage and controlled microstructure can, however, be developed using alumina powder from Bayer's process and fused alumina grains with MgO in the form of magnesio-aluminate hydrate (MAH) as sintering aid. By introducing fine alumina powder pre-calcined at an optimum temperature, a part of fused alumina grains can be replaced. The possibility of formation of bodies involving the entire range of graded fused alumina and fine technical alumina powder has been explored.
1 citations
TL;DR: In this article, a feasibility study was carried out on the fabrication of laboratory wares using indigenously available zircon by the slip casting technique, and two types of ZIRcon powders having different particle sizes were used for the study.
Abstract: A feasibility study was carried out on the fabrication of laboratory wares using indigenously available zircon by the slip casting technique. Two types of zircon powders having different particle sizes were used for the study. The cast wares were sintered at temperatures between 1500° and 1600°C. Evaluation of materials during the various stages of fabrication was followed by bulk density and microstructure determination. It was revealed by X-ray analysis that dissociation of zircon into zirconia and silica did not take place during the course of sintering.
TL;DR: In this article, the diffusivities of hydroxyl and molecular water species were obtained at different pressures and fugacities, and the solubility of molecular water was observed to decrease with pressure while it increased linearly with fugacity.
Abstract: Diffusion of water in silica glass was studied under high pressure and water fugacities. To clarify the role of each parameter, experiments were conducted by varying the pressure at constant fugacity and by varying the fugacity at constant pressure. Concentrations of diffusing substances were obtained using FTIR spectroscopy. The solubility of molecular water species was observed to decrease with pressure while it increased linearly with fugacity. The diffusivities of hydroxyl and molecular water species were obtained at different pressures and fugacities.
TL;DR: In this article, a simple stepwise complexometric method with EDTA has been developed for the determination of zirconium and yttrium in a single aliquot solution involving direct titration of ZIRconium at 1N HNO3 and 90°C and of Yttrium at pH 5.3 using methyl thymol blue as indicator.
Abstract: A simple stepwise complexometric method with EDTA has been developed for the determination of zirconium and yttrium in a single aliquot solution involving direct titration of zirconium at 1N HNO3 and 90°C and of yttrium at pH 5.3 using methyl thymol blue as indicator. Interferences due to Fe, Ti, Al and Cu have been eliminated by masking with acetylacetone. The method has been standardised against synthetic solutions and applied to various zirconia-yttria ceramics and other yttria bearing materials.
TL;DR: In this paper, the authors carried out X-ray, DTA, IR spectroscopy, and physical chemical and mineralogical studies to find utilization of a black clay from Rajpardi in Gujarat in ceramic industries.
Abstract: Physico-chemical and mineralogical studies (X-ray, DTA, IR spectroscopy) were carried out to find utilization of a black clay from Rajpardi in Gujarat in ceramic industries. It was noticed that the Rajpardi clay contains predominantly kaolinite having characteristics like Bikaner ball clay. Attempts were also made to use the clay as a substitute of Bikaner ball clay in the manufacture of ceramic products to make it cost effective, particularly for the ceramic industries in and around Gujarat The results show that Rajpardi clay can be suitably used along with Bikaner ball clay in the manufacture of ceramic wares.
TL;DR: In this article, simple titrimetric methods have been described for determination of aluminium and fluorine after selective separation of aluminium from fluorine using TBP-plasticized polyurethane foam sorbents.
Abstract: Simple titrimetric methods have been described for determination of aluminium and fluorine after selective separation of aluminium from fluorine using TBP-plasticized polyurethane foam sorbents. The extraction of aluminium from 0.20 to 0.30M NaOH solution has been found to be quantitative at 25°C. The sorbed aluminium complex can be eluted with 1M HC1 and determined titrimetrically at pH ∼ 5.3 with EDTA by the back titration method using xylenol orange as indicator. Fluorine left in the aqueous part has been determined titrimetrically with standard thorium nitrate solution in presence of 40% acetone at pH 3.0 ± 0.2 using sodium alizarin sulphonate as indicator. Anions like—PO43-, SiO32-, AsO32-, VO3−, CrO42-, BO33-, MnO42-, MnO4− and GaO2−″ have no effect on the extraction of aluminium as well as on the determination of fluorine. Both the methods have been standardised against standard samples.
TL;DR: Very poor compaction occurs in case of technical grade alumina powders produced by Bayer's process as discussed by the authors, which does not follow any powder compaction models suggested in the case of other irregular shaped ceramic powders.
Abstract: Very poor compaction occurs in case of technical grade alumina powder produced by Bayer's process. Ground, washed and dried technical alumina powder yields low green density (47% theoretical) even by isostatic pressing (2000 kg.cm−2 forming pressure) and does not follow any powder compaction models suggested in the case of other irregular shaped ceramic powders. Precalcination of the processed fine powders (0.3 to 0.4 μm) between 1100° and 1600°C causes reduction of the void volume present in the agglomerated powder resulting in better densification (∼70% theoretical) obtained at 1550 kg.cm−2 forming pressure. More than 80% theoretical density in the green stage was possible with fused alumina grains incorporated with processed technical alumina powder at 1550 kg.cm−2 forming pressure.
TL;DR: The composite high Tc superconductor of YBCO and ceramicmetal BaPbO3 has been synthesized via solid state sintering technique by adding PbS to the starting materials.
Abstract: The composite high Tc superconductor of YBCO and ceramicmetal BaPbO3 has been synthesized via solid state sintering technique by adding PbS to the starting materials. Sulphur ions of PbS were found to substitute for oxygen in YBCO material whereas Pb ions preferred to form BaPbO3 which got segregated near grain boundaries of Y-123 phase, forming a composite microstructure. The composite ceramics, having Tc well above liquid nitrogen temperature, had three to four times higher flexural strength as compared to pure YBCO. These materials are good candidates to be used in superconducting devices and sensors.
TL;DR: For a critical concentration of 0.25 mol% Nb2O5, the dielectric constant of the material was found to be 0.4H2O as mentioned in this paper.
Abstract: Various mol% of Nb2O5 were incorporated into BaTiO3 during its preparation in the form of BaTiO(C2O4)2.4H2O. For a critical concentration of 0.25 mol% Nb2O5, the dielectric constant of the material...
TL;DR: The development of ceramic heads for hemi-hip prosthesis implants which have been implanted to 18 different human patients revealed no abnormal clinical effect on the patients after 2 years of implantation.
Abstract: In recent years polycrystalline alumina ceramics have been widely used as bioceramic implants in various orthopaedic applications in western countries. Alumina ceramics have been proved to be more biocompatible, resistant to corrosion and abrasion over conventional metals and, therefore, higher durability of the implants is envisaged.The present paper deals with the development of ceramic heads for hemi-hip prosthesis implants which have been implanted to 18 different human patients. Physical and mechanical characteristics and biocompatibility of these ceramic heads have been examined in short term clinical studies. The study revealed no abnormal clinical effect on the patients after 2 years of implantation.
TL;DR: In this article, the authors studied the properties of fractional volume compaction at different forming pressures and found that fractional volumes compaction depends on the agglomerated structures developed during calcination along with other parameters, viz. particle size, shape and hardness.
Abstract: Compaction behaviour of monosized (∼1 μm) alumina powder dried (110°C) and calcined at different temperatures, viz. 1000°, 1300°, 1375°, 1500° and 1600°C was studied and the results were analysed on different compaction models in general and Cooper and Eaton's model in particular. The results revealed that fractional volume compaction (V*) at different forming pressures depends on the agglomerated structures developed during calcination along with other parameters, viz. particle size, shape and hardness. Powder calcined at 1000°C produced greater compaction compared to powders calcined at other temperatures at a given forming pressure. Analysis of results according to Cooper and Eaton's model suggested the development of a property due to the change of morphological behaviour during calcination at different temperatures.