Showing papers in "Transactions of The Indian Ceramic Society in 1980"
TL;DR: In this paper, the effect of temperature on the line shape of the ultraviolet absorption bands of chromium (VI) in different (1-x) Na2O, xB2O3 (where x varied from 0.1 to 0.33), and in a 0.7SiO2 glass was studied.
Abstract: The effect of temperature on the line shape of the ultraviolet absorption bands of chromium (VI) in different (1-x) Na2O, xB2O3 (where x varied from 0.1 to 0.33), and in a 0.3Na2O, 0.7SiO2 glass was studied. The ultraviolet absorption of chromium (VI) in these glasses is characterised by two charge transfer bands centred around 250–270 nm and 350–370 nm, the location of the centre of absorption and relative intensities of the two bands depending on the borochromate/chromate ratio in the glass which in turn is dependent on the chemical composition of the glass. The 350–370 nm band has been found to be Gaussian at the top half of absorption, and exponential with wave-number at the low-energy tail of the band obeying Urbach's Rule. In all the glasses, the energy of absorption maximum decreased linearly with increasing temperature, and the bands became broader. The change in intensity of chromium (VI) absorption in different glasses with varying temperature has a satisfactory correlation with thermal expansio...
20 citations
TL;DR: In this article, the authors review the theory and practice of particle packing and highlight the practical applications of packing of particles, such as multiscale particle compaction, shape, size and size distribution, etc.
Abstract: The paper reviews the theory and practice of particle packing. Work on the packing of solid particles mainly consisted of (a) theoretical calculation of voidage due to different modes of packing of rigid unisized spherical particles, (b) theoretical calculation of voidage for multicomponent particulate system, (c) experimental compaction of unisized spherical as well as irregular particles of different sizes, (d) experimental compaction of multi-component system to obtain denser beds and (e) correlation of variables, such as methods of compaction, shape, size and size distribution of particles as well as the size of the container, etc. The paper also highlights the practical applications of packing of particles.
14 citations
TL;DR: In this paper, it was shown that the red color formation in copper-ruby glasses was due to the presence of the particles of colloidal copper, and not due to colloidal Cu2O.
Abstract: Absorption spectra relating to the photosensitive copper-ruby and normal copper-ruby glasses revealed a strong absorption band at 560 mμ. The shapes of the absorption curves for the photosensitive copper-ruby and normal copper-ruby glasses were almost similar. Electron microscopic study also revealed the presence of the particles of colloidal copper in the size range of 20–60 mμ both in photosensitive as well as in the normal copper-ruby glasses. The results obtained showed that the red colour formation in copper-ruby glasses was due to the presence of the particles of colloidal copper, and not due to the particles of colloidal Cu2O.
8 citations
TL;DR: In this article, the use of clay as filler and reinforcement in metals, as a source of Al-Si alloys and as a material for making light weight insulating materials have been discussed.
Abstract: The clay reserves of Kerala as well as of India as a whole and the world have been reviewed. Fine mapping charts of conventional and non-conventional uses of clay have been given. All uses have been indexed in consideration of their applicability and adaptation in India. A table giving the amount of various clays used in different Indian industries has been made. Certain new uses of clay as filler and reinforcement in metals, as a source of Al-Si alloys and as a material for making light weight insulating materials have been discussed. The imperative to develop new processes for some of the newer clay-based products have been listed. The role of clay in alleviating the energy crisis by acting as insulating materials and acting as a means of producing oxygen enriched air has been amplified. Research activities on clays in India have been discussed. The world-wide need to use materials based on abundant alumino-silicate materials in place of scarcer materials has been elaborated.
3 citations
TL;DR: A type of moisture tester, depending upon the principle of dielectric absorption at radio-frequency, has been designed on solid-state circuit for scanning surface dryness of huge refractory bodies, whitewares and moulds as discussed by the authors.
Abstract: A type of moisture tester, depending upon the principle of dielectric absorption at radio-frequency, has been designed on solid-state circuit for scanning surface dryness of huge refractory bodies, whitewares and moulds. It has got the advantage of testing the articles, in situ, prior to firing and thus to avoid fire-cracks and chipping during the process. © 1980 Taylor & Francis Group, LLC.
2 citations
TL;DR: In this paper, a preliminary effort has been made to incorporate SS 304 type steel fibre in a chrome-based plastic refractory and trials conducted with this material for reheating furnace applications have been found encouraging.
Abstract: In recent years, various metal fibre reinforced ceramic systems have been investigated with the object to overcome low tensile strength and thermal shock resistance of conventional ceramic materials. In this paper fibre characterization, strengthening mechanism, properties and successful applications of steel fibre reinforced refractories have been reviewed.In the author's plant, a preliminary effort has been made to incorporate SS 304 type steel fibre in a chrome-based plastic refractory. Trials conducted with this material for reheating furnace applications have been found encouraging.
2 citations
TL;DR: In this paper, three different thick film printing paste compositions were prepared by mixing ruthenium dioxide with PbO-MgO-GeO2glasses in such a proportion so as to maintain a constant volume ratio and by addition of an appropriate amount of organic vehicle.
Abstract: Three different thick film printing paste compositions were prepared by mixing ruthenium dioxide with PbO-MgO-GeO2glasses in such a proportion so as to maintain a constant volume ratio and by addition of an appropriate amount of organic vehicle The pastes so prepared were printed on alumina substrates, dried on a hot plate and fired Ohmic resistance and TCR were measured It was observed that TCR was closely related to the relative coefficient of thermal expansion of the glass and the ceramic material of the substrates © 1980 Taylor & Francis Group, LLC
2 citations
TL;DR: In this article, a case study has been reported on the presence of excessive amounts of alkali in raw materials, the ring problem and suggested remedies, and the situation has to be reviewed in the context of constraints on the availability of good raw materials and fuel for the cement industry.
Abstract: The problems associated with alkali in cement making need suitable appreciation with the number of dry process plants increasing in the country. Besides, the situation has to be reviewed in the context of constraints on the availability of good raw materials and fuel for the cement industry. Generally, volatiles create cycles which ultimately lead to build-ups in preheaters, rings in kilns in addition to causing occasionally damage to refractory linings. Apart from reviewing the different aspects of the problem in detail, a case study has been reported on the presence of excessive amounts of alkali in raw materials, the ring problem and suggested remedies.
2 citations
TL;DR: In miniature electronic systems, sintered alumina ceramic wafers are used as substrates for printed circuits, due to their high degree of reliability as well as performance as discussed by the authors.
Abstract: In miniature electronic systems, sintered alumina ceramic wafers are used as substrates for printed circuits, due to their high degree of reliability as well as performance. The techniques and present status of preparation along with properties and surface characteristics requirements in electronic applications have been presented.
1 citations
TL;DR: In this paper, a simple flame-photometric method has been worked out in which calcium radiation signal is first completely quenched and subsequently released by the addition of adequate amount of magnesium.
Abstract: The interfering effects due to various ceramic constituents such as aluminium, titanium, zirconium and alkalies on the radiation signal of calcium have been critically studied in both hydrochloric and sulphuric acid media using a Oamephotometer with light filter and low flame temperature such as town gas, air or LPG air-flame. It has been observed that in hydrochloric acid medium Al, Ti and Zr have quenching effect on the radiation signal of calcium even at low concentrations while in sulphuric acid medium it has hardly any effect when Al: Ca and Ti: Ca ratios are less than 1/5 and Zr: Ca ratio is less than one. It has also been observed that the radiation signal of calcium is almost completely quenched when the Al: Ca, Ti: Ca and Zr: Ca ratios are � 5, � 4 (� 8 in HCl) and � 20 respectively in HCl and H2SO4media due to the formation of CaO, Al2O3; CaO, TiO2and CaO, ZrO2spinels. Magnesium in concentration of 200 or more times of calcium can quantitatively release calcium from Al, Ti and Zr in the range present in alumino silicates only in H2SO4medium due to the preferential formation of MgO, Al2O3spinel. Based on these observations, a simple flame-photometric method has been worked out in which calcium radiation signal is first completely quenched and subsequently released by the addition of adequate amount of magnesium. The method is accurate, sensitive and utilized for determination of smaU amount of calcium in various ceramic materials. © 1980 Taylor & Francis Group, LLC.
1 citations
TL;DR: In this paper, the authors present some aspects of the current knowledge on the phenomenon of ion exchange in zeolites, the important criteria that are involved, and the modifica · tions in properties that follow complete or partial exchange of sodium in synthetic faujasite-type zeolite.
Abstract: Natural and synthetic crystalline zeolites are characterized by frameworks originating from linkages of (Si, Al)-tetrahedra, in which structural cages and channels are occupied by water molecules and an appropriate amount of non· framework cations for balancing the negative charge of the available (AlO2)-groups. Most common among these non-framework cations are Na+, Ca2+and K+(in both natural and as-synthesized zeolites). Reversible and facile exchange of these cations with others is one of the characteristic properties of zeolites. The extents of such exchanges are guided by factors like crystallographic sites and structural openings involved, ionic hydration energies, hydrated radii of the ions etc. Technologically important ion exchanges in zeolites include Ni2+, RE3+(e.g. La3+, Ce3+) and NH4 +for sodium. The present paper discnsses some aspects of the current knowledge on the phenomenon of ion-exchange in zeolites, the important criteria that are involved, and the modifica· tions in properties that follow complete or partial exchange of sodium in synthetic faujasite-type zeolites. Special emphasis has been given on the development of catalytic activity in these zeolites by virtue of ion exchange and subsequent activation. © 1980 Taylor & Francis Group, LLC.
TL;DR: Sintered zircon grog has been used in the manufacture of high quality zIRcon refractories used in iron and steel industries as discussed by the authors, where the quality of the refractory largely depends upon the quality and quantity of the sintered grog used.
Abstract: Sintered zircon grog finds application in the manufacture of high quality zircon refractories used in iron and steel industries. The quality of these refractories largely depends upon the quality of zircon grog used.Attempts were made to develop high quality grog from the indigenous raw materials such as zircon sand and ground zircon powder of various grades. The sintering behaviour of these powders along with additives such as clay, dolomite and CaO-MgO mixtures has been studied with a view to incorporate the additives to a minimum extent to the zircon sand, which is a major constituent and a relatively cheap raw material used for making sintered zircon grog. The properties of the grog aimed at comprise: water absorption 61%. Properties such as open porosity, bulk density and water absorption attained in the sintered grog have been studied over a temperature range of 1400°–1550°C.Sintered zircon grog, crushed to various grain sizes has been further experimente...
TL;DR: In this article, a simple and rapid complexometric method for stepwise titration of Ca and Mg, and Mn in blast furnace slags and manganese minerals has been worked out without involving any separation of Manganese.
Abstract: A simple and rapid complexometric method for stepwise titration of Ca and Mg, and Mn in blast furnace slags and manganese minerals has been worked out without involving any separation of manganese. The method is based on the joint titration of Ca and Mg at pH 10 using naptholgreenorthocresolphthalein-ammonium chloride mixed indicator after masking manganese effectively with KCN and bubbling air through the solution (30° -40°C) for 10 minutes. Manganese is then titrated at the same pH in the presence of indicator solution containing eriochrome black T, titan yellow and triethanol amine after reducing the Mn (III) hexacyano complex to Mn (II) cyanide complex with ascorbic acid. Calcium is, however, determined from a separate aliquot by direct titration with EDTA using calcein-thymolphthalein indicator after masking Mn with TEA and K CN. © 1980 Taylor & Francis Group, LLC.
TL;DR: In this paper, X-ray diffraction and infra-red carried out on samples of massive sillimanite and quartz-free quartz-sillimanite schist from Sonapahar area as such, as well as on tiny single crystals, picked up therefrom, under a microscope indicated the presence of mullite beside four, forms of sheroneite.
Abstract: Investigation by X-ray diffraction and infra-red carried out on samples of massive sillimanite and quartz-free quartz-sillimanite schist from Sonapahar area as such, as well as on tiny single crystals, picked up therefrom, under a microscope indicated the presence of mullite beside four, forms of sillimanite. Rutile and biotite were also found to occur in the schist. Densities of three forms of sillimanite were found to be 3.22, 3.19, 3.26 gm/cc but density of mullite was 3.06 gm/cc.
TL;DR: In this paper, the reaction of synthetic gibbsite (well and poorly crystalline) has been studied by X-ray diffraction, thermal gravimetric and differential thermal analysis.
Abstract: Dehydration reactions of synthetic gibbsite (well and poorly crystalline) have been studied by X-ray diffraction, thermal gravimetric and differential thermal analysis. Crystallite size of the ordered material has been calculated from diffraction line broadening of X-ray reflections and for highly disordered gibbsite the grain size is calculated from electron micrographs. The activation energies of dehydration of gibbsite → boehmite and gibbsite → x-Al2O3 have been evaluated.
TL;DR: In this paper, a systematic investigation was undertaken using the glasses from the following systems (i) Na2O-CaO-SiO2, (ii) Li2O/CaO/SiO 2, (iii) Li 2O/La2O3/BaO/CeO2/Si O 2 ) for pH measurement.
Abstract: Blood capillary glass electrode, a recent development in medical electronics is used in conjunction with anaesthesia monitoring equipment to observe and record the hydrogen ion concentration of blood, particularly when the patient undergoes a surgical operation. With a view to develop the electrode, a systematic investigation was undertaken using the glasses from the following systems (i) Na2O—CaO—SiO2, (ii)Li2O—CaO—SiO2, (iii) Li2O—La2O3—Cs2O—SiO, (iv) Li2O—La2O3—BaO—CeO2—SiO2. The glasses were melted and capillary tubes were drawn. Keeping in view the monitoring system in medical electronics, an arrangement was set up for ascertaining the suitability of the capillary fibres made out of the glass for pH measurement.It was found that only glass no. (iii) responded to the activity of hydrogen ions and produced slope values very close to the ideal Nurnst value at room temperature when the measured emf data were plotted against the corresponding pH showing thereby that the remaining three glasses were not su...
TL;DR: In this article, the use of silica grog for making bricks was restricted due to its high grain porosity and inversion of cristobalite at lower temperature which seriously affects the bond strength.
Abstract: During the dismantling of coke ovens, large quantity of silica waste was recovered and an investigation was undertaken to find out suitable means to utilize these materials. The use of silica grog for making brick was restricted due to its high grain porosity and inversion of cristobalite at lower temperature which seriously affects the bond strength.Work was undertaken to develop proper composition with suitable binders for making bricks utilizing the silica waste. The bricks were made and tried in the ladles used for transferring blown metal from Bessemer Shop to Open Hearth furnace. Encouraging results were obtained in the initial trials.
TL;DR: In this article, the nature of formation of compounds between monocalcium aluminate and organic acids such as salicylic, anthranilic and sulphanilic acid was studied by infra-red spectroscopy.
Abstract: The nature of formation of compounds between monocalcium aluminate and organic acids such as salicylic, anthranilic and sulphanilic acid taken in the ratio of 1:1,10:1 and 100:1 respectively was studied by infra-red spectroscopy. Salicylic and anthranilic acids deprotonate to form resonance stabilized chelate structures with hydrated alumina while sulphanilic acid deprotonates to form bridged complexes in the cementitious phase.
TL;DR: A note on China Clay Resources of West Bengal is given in this article, where the authors discuss the use of China clay resources in West Bengal and India's coal mining history in detail.
Abstract: (1980). A Note on China Clay Resources of West Bengal. Transactions of the Indian Ceramic Society: Vol. 39, No. 5, pp. 180-186.
TL;DR: Sintered alumina ceramic substrates are in increasing demand for use in micro-electronics as mentioned in this paper, and usually two processes of manufacturing are industrially employed: tape casting and Sintered Alumina Ceramics.
Abstract: Sintered alumina ceramic substrates are in increasing demand for use in micro-electronics. Usually, two processes of manufacturing are industrially employed. Substrates made by tape casting are com...
TL;DR: In this paper, the theories of slag constitution are discussed in relation to ionic melts, and the concepts are tested by making a formal distinction between methods in which ionic species and units of liquid structure are chosen as components.
Abstract: The theories of slag constitution are discussed in relation to ionic melts, and the concepts are tested by making a formal distinction between methods in which ionic species and units of liquid structure are chosen as components. A phase integral analysis shows the existing “theories” to be essentially arbitrary. The limitations of the so called “evidences” for discrete species are also discussed.
TL;DR: In this article, the chemical and rational analyses of the samples indicate the range of variation of the different constituents of the coal seams in Bina and Jhingurdah mines, and the infra-red and x-ray diffraction techniques were adopted along with the DTA and TGA techniques for determination of clay and other minerals.
Abstract: Clay samples exposed over Barakar and Raniganj coal seams of lower gondwana system in Bina and Jhingurdah mines respectively have been studied. The chemical and rational analyses of the samples indicate the range of variation of the different constituents. The infra-red and x-ray diffraction techniques were adopted along with the DTA and TGA techniques for determination of clay and other minerals.
TL;DR: In this paper, the effect of foreign ions, which reacted with colloidal micelles of silica in solution, was evaluated with different additives for finding out the effect on strength and setting characteristics with aluminous and siliceous base materials.
Abstract: Soluble silicate (sodium silicate) has been used as bond in ceramic and refractories industry for a long time. The versatile nature of this material resulting from alkali silica reaction offered several advantages in many fields of refractory application. Additional advantages with respect to strength and rapid setting can be obtained by incorporating foreign ions, which reacted with colloidal micelles of silica in solution. Studies were undertaken with different additives for finding out the effect on strength and setting characteristics with aluminous and siliceous base materials. The mixtures were fired at various temperatures and their properties were evaluated.
TL;DR: Carbon and carbon deposits have been found to be increasingly useful for a wide variety of applications ranging from rocket and missile hardware to medical prosthesis, and the pyrolite carbon is now universally acclaimed as most suitable.
Abstract: Carbon and carbon deposits have been found to be increasingly useful for a wide variety of applications ranging from rocket and missile hardware to medical prosthesis. Implants and artificial organs made out of various ceramic materials are being increasingly considered in surgery. Perhaps, the most striking application is in the use of carbon for heart valve prosthesis. Surgical replacement of defective heart valves is at least well-nigh two decades old. Bioengineering studies with respect to design, material and compatibility with biological systems have made very rapid strides ever since cardiac valve replacement was conceived as a practical feasibility. Of various types of materials studied for valve prosthesis, the pyrolite carbon is now universally acclaimed as most suitable. The choice of carbon for such seemingly contradictory applications originates to the fact that it can be tailor-made to one's requirement due to remarkable variation in its crystallinity. This paper deals with the type of carbo...
TL;DR: In this article, the effect of various ketones and ketonic mixtures on the stability and sensitivity of ferric thiocyanate color in aqueous solution has been systematically studied.
Abstract: The effect of various ketones and ketonic mixtures on the stability and sensitivity of ferric thiocyanate colour in aqueous solution has been systematically studied. Maximum increase in intensity (about 2 times) and stability (more than 4 hours) of the coloured complex has been observed in aqueous solution containing a mixture of methyl ethyl ketone and acetone in the ratio from 2:1 to 1:2 and having an overall pH from 1.4 to 1.7. Below pH 1.4, the ferric thiocyanate colour separates out in the upper layer of the solution while its stability and intensity of colour decrease with the increase of pH above 2. 7. Large amounts of zinc which interfere with the determination of iron by orthophenanthroline method do not have any adverse effect on the ferric thiocyanate colour. Based on these observations, a simple and sensitive procedure has been worked out for determination of small amounts of iron in zinc oxide and other zinc minerals. © 1980 Taylor & Francis Group, LLC.