Showing papers in "Transactions of The Indian Ceramic Society in 2011"

Organophilic Nano Clay: A Comprehensive Review

Abstract: Organophilic nano clay is an important organic-inorganic hybrid derived from intelligent combination of two dissimilar components, viz. clays and organic molecules, at the nanometric and molecular level. The clay component of this hybrid provides a 2-D lamellar structure with interesting surface chemistry, which can be engineered by organic molecules. 2:1 layered clay minerals with high cation exchange capacity, e.g. montmorillonite, possess cation exchange sites on the siloxane surface which can be exchanged with suitable organic molecules. Key aspect of this organic treatment is to swell the interlayer space of the clay mineral up to a certain extent reducing interlayer interaction, to produce nanoplatelet of aluminosilicate materials. Those engineered nanoplatelets are used in various fields of applications, viz. polymer nano clay composite, rheological modifier, thickening and gelling agent in paints and lubricants, in waste water treatment, and also as drug delivery vehicle. Intensive research activi...

Synthesis and Characterization of SrAl2O4:Eu2+, Dy3+ Nanocrystalline Phosphorescent Pigments

Abstract: In this research, the Eu2+ and Dy3+ co-doped strontium aluminate (SrAl2O4) nanocrystalline phosphorescent pigments with high brightness and long afterglow was successfully synthesized by urea-nitrate solution combustion method (SCS) at 600°C, followed by heating the resultant combustion ash at 1200°C in an atmosphere which was weak reducing (5%H2 + 95%N2). The pure SrAl2O4 monoclinic phase as host structure could be formed by combustion method in which the temperature is very much lower than solid-state method. A broad-band UV-excited luminescence of the SrAl2O4:Eu2+, Dy3+ phosphorescent pigments was observed at λmax = 517 nm due to transitions from 4f65d1 to 4f7 configuration of the emission center (Eu2+ ions). The excitation spectra showed two main peaks at 240 and 256 nm. Eventually, the average grain size of the combustion ash powder and SrAl2O4:Eu2+, Dy3+ phosphor particles were obtained as 40 and 62 nm, respectively via Scherrer’s formula and these particles were in thin flake form.

Synthesis and Characterization of Co-Doped Ceria Ceramics by Sol-Gel Method

Abstract: Doped and co-doped ceria electrolyte materials are very useful in solid oxide fuel cells. The Ce0.9Sm1−xSrxO2 (x = 0–0.09) compositions were synthesized through the sol-gel method. Dense Ce0.9Sm1−xSrxO2 ceramics were obtained through sintering the pellets at 1300°C for 8 h. XRD measurements indicate that all synthesized materials crystallized in cubic fluorite-type structure. Average crystallite size of the samples was in the range 21–27 nm. The relative density of Ce0.9Sm1−xSrxO2 samples was over 94% of the theoretical density. The lattice parameter increased linearly with increasing Sr concentration in Ce0.9Sm1−xSrxO2 following Vegard's rule. Surface morphology was analyzed using SEM. It was observed that the thermal expansion increased linearly with increasing temperature. The two-probe a.c. impedance spectroscopy was used to study the grain, grain boundary and total ionic conductivity of doped and co-doped ceria in the temperature range 250°–500°C. The Ce0.9Sm0.07Sr0.03O2 composition showed higher gra...

Synthesis and Characterization of Nanocrystalline TiO2 Thin Films for Use as Photoelectrodes in Dye Sensitized Solar Cell Application

Abstract: In the event of escalating gasoline prices resulting from threatened oil reserves and nuclear meltdowns endangering the quality of life in near future it is expected that science would make priceless contributions to green technology and come up with environment friendly solutions. Third generation photovoltaic solar cells have attracted researchers in this respect. Dye-sensitized solar cell (DSSC) is a novel category of economical photovoltaic cell that belongs to the group of thin film solar cells. The ability of developing and modifying nanoparticles has given scope to produce dye sensitized solar cells with a principle similar to that of photosynthesis. Promising efficiencies of around 11% have given scope for investment and advancement of this sector to get cheaper renewable solar energy available in abundance. The underlying principle uses a network of nanocrystalline TiO2 on a glass plate coated with transparent conducting oxide. Sensitization of nanocrystalline TiO2 network with dye enhances the e...

Synthesis and Characterization of Nano Silicon Carbide Powder from Agricultural Waste

Abstract: In this study nanoparticles of SiC were produced through direct pyrolysis of rice husk. The major inorganic component of rice husk is silica, which is highly pure, amorphous, with large surface area and highly reactive. Rice husk used in this study was treated with a silica source in order to enrich the silica content. The synthesis was carried out in an argon atmosphere at 1600°C. Activation energy for the formation of SiC was calculated using Arrhenius equation and found to be 110 kJ.mol−1 for raw rice husk and 139 kJ.mol−1 for treated rice husk. The SEM study of pyrolysed rice husk shows that whiskers formed in the silica rich zone and particles formed in the carbon rich zone.

Advantages of Nano Pigments Over Micro Pigments in Obtaining Larger Spectra of Colours in CMYK System

Abstract: Based on the CMYK colour system, it is possible to obtain the full colour spectrum with mixing the four colours – cyan, magenta, yellow and key (black). In this research, ceramic nano pigments including CoAl2O4 (cyan), Au (magenta), (Ti,Cr,Sb)O2 (yellow) and CoFe2O4 (key) were mixed together with different ratios and applied on glazed tiles and the colour specifications of the samples were measured. The Colours Software (CSA) was used for predicting the ratios of the pigments for obtaining a target or reference colour. For comparison, equivalent micro pigments, namely CoAl2O4, Cd(S,Se):ZrSiO4, (Ti,Cr,Sb)O2 and CoFe2O4 were also examined. It was observed that using the present nano pigments, it was possible to cover the fourth quarter of the CIELab circle close to a + axis, while this was not possible with the micro pigments. This was attributed to the blue tint present in Au nano pigment. It was also revealed that reaching the colours of grey, brown and beige shades was possible by both nano and micro set...

Effect of Adiabatic Flame Temperature on Nano Alumina Powders during Solution Combustion Process

Abstract: Materials Research Centre Indian Institute of Science Bangalore – 560 012, IndiaNano ceramic alumina powders are synthesized by solution combustion synthesis using aluminium nitrate as oxidizer and urea as fuel with different fuel to oxidizer ratio. The variation of adiabatic flame temperatures are calculated theoretically for different fuel/oxidizer ratio according to thermodynamic concept and correlated with the observed flame (reaction) temperatures. A “multi channel thermocouple setup connected to computer interfaced Keithley multi meter 2700” is used to monitor the thermal events occurring during the process. The combustion products, characterized by XRD, show that the powders are composed of polycrystalline oxides with crystallite size of 32 to 52 nm. An interpretation based on maximum combustion temperature and the amount of gases produced during reaction for various fuel to oxide ratio has been proposed for the nature of combustion and its correlation with the characteristics of as-synthesized powder.

Synthesis, Characterization and Catalytic Activities of Titania based Nanocatalysts for the Degradation of Carcinogenic Imidacloprid

Abstract: A greener water treatment technique is required to eliminate the hazardous and carcinogenic chemicals such as pesticides, insecticides, etc from contaminated water. Photocatalysis based on titania are the excellent materials to achieve complete degradation of the agro chemicals. In this work, nanocrystalline titania and strontium titanate have been synthesized by sol-gel process. Doping of titania based catalysts with metal or non-metal elements decreases the bandgap and hence increases the photo efficiency. Synthesized titania and strontium titanate have been doped by multielements (C, N, B, F) and Ni/Ru respectively. The catalysts have been characterized by XRD, UV-DRS, SEM and TEM. The synthesized catalysts have been tested for their catalytic activity towards the degradation of carcinogenic insecticide imidacloprid using multilamp photo reactor. The reaction parameters such as initial concentration of insecticide, catalyst weight and pH have been optimized and the results were discussed.

Studies on the Suitability of Iron-rich Indian Bentonites for Synthesis of Organoclays by Intercalation

Abstract: In the present study intercalation behaviour of two bentonites from Indian origin were compared with a high-puritycommercial montmorillonite. Experimental bentonites of Indian origin showed low cation exchange capacity (CEC) due to limited Mg2+ substitution. Infra-red spectral study revealed the presence of Fe3+ in octahedral positions. Organic loading of intercalated clays increased with CEC.

Synthesis and Characterization of Pure CdS Nanoparticles for Optoelectronic Applications

Abstract: Pure CdS nanoparticles were synthesized by using a simple aqueous precipitation method at room temperature. The CdS nanoparticles were then subjected to low temperature heat treatment at 200°C for 2 h. The prepared powder was characterized by various analytical techniques such as powder XRD, SEM, TEM, thermal and spectroscopic analyses. XRD study confirmed the high crystalline nature of prepared compounds and the presence of hexagonal and cubic phases of the CdS nanoparticles. The particle size of CdS nanoparticles were calculated by Scherrer's formula and it was found that the particles were in the range of 8 to 10 nm. SEM images confirmed the homogeneous distribution of the nanoparticles. Photoluminescence studies of CdS nanoparticles showed green emission with peak intensity maximum at 535 nm. Raman spectra of the as-prepared and heat treated samples were recorded using Laser-Raman technique. The bandgap of the CdS particles was calculated from the absorption edge of the UV-Vis spectrum and was found t...

Microstructural and Mechanical Properties in Traditional Ceramics as a Function of Quartzofeldspathic Sand Incorporation

Abstract: We intend to study the influence of addition of quartzo-feldspathic sand on the mechanical properties and the microstructure of Tunisian illite-kaolinite clay ceramics. The fired characteristics of the clay and quartzo-feldspathic sand mixtures have been studied separately at soaking temperatures reaching respectively 850°, 950° and 1050°C during a firing profile of ∼7–8 h. Investigation of phase transformations of the mixed samples shows that albeit the proportion of the quartz has been increased, its peak intensity remains constant. Such stability may be explained by quartz dissolution in the glassy phase. The mechanical strength of the mixed samples has been examined in terms of flexural strength. In the studied case, the latter increases from 13.5 to 23.3 N.mm−2 as the sample becomes denser in the mixture M2. It may also be noticed that an overdose of quartz reduces the mechanical strength. Hence, a moderate addition of well-sorted fine quartzofeldspathic sand ameliorates the mechanical properties and...

Solution Combustion Synthesis and Photocatalytic Activity of α-Fe2O3 Nanopowder

Abstract: Nanocrystalline α-Fe2O3 was prepared using solution combustion method with glycine as fuel and ferric nitrate as oxidizer at about 300oC. The α-Fe2O3 nanopowder was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The PXRD pattern indicates that the α-Fe2O3 has hexagonal phase with a mean crystallite size of 30–40 nm as calculated from Scherrer's formula. The iron oxide nanopowder was used for the photocatalytic degradation of methyl orange (MO) dye in aqueous solution. The effects of catalyst dosage, H2O2 and irradiation time on the rate of photocatalytic degradation of MO dye were also investigated. The rate of photocatalytic degradation of MO dye was enhanced in the presence of H2O2 and UV light. The experimental results show that for concentration of 20 ppm, maximum decoloration of the dye solution was achieved in just 25 min for a catalyst dosage of 2.5 g per liter of the dye solution.

Preparation and Characterization of Porous Cordierite Ceramics with Well-distributed Interconnected Pores

Abstract: Porous cordierite ceramics with well-distributed interconnected pores were prepared by pore forming in situ technique coordinated with adding pore forming agent. The phase, microstructure, strength and gas permeability were investigated through X-ray diffractometer, scanning electron microscopy, mercury porosimetry measurement, etc. The proper sintering temperature was found to be 1360°C when the porous cordierite ceramics were fabricated through pore forming in situ technique. The porous cordierite ceramics sintered at 1360°C has high cordierite phase content, high apparent porosity (40.3%), homogeneous pore size distribution and interconnected pores, thus the porous cordierite ceramics also has high compressive strength (54.5 MPa) and high gas permeability (2.31 m2). With the addition of sawdust as pore forming agent, the porosity and the gas permeability of the porous cordierite ceramics sintered at 1360°C increased, however, the strength decreased. For example, addition of 6% sawdust resulted in 47.9%...

Synthesis and Characterization of CNT Reinforced Alumina based Nanocomposite

Abstract: Carbon nanotube (CNT) reinforced alumina matrix nanocomposite was successfully synthesized by two different techniques. In the first process sol-gel method was used to generate 3 wt% homogeneously distributed CNT in alumina matrix after sintering. In another novel method chemical mixing process was adopted for synthesis of CNT-alumina nanocomposite powder to generate maximum of 10 wt% CNTs in the alumina matrix after sintering. Phase identification was done by XRD and the particle size was measured by Scherrer and Williamson-Hall plot. Compared to pure alumina the hardness of the nanocomposite was improved by 3–18% for different wt% of CNTs. The hardness of the nanocomposite enhanced due to an enhanced load carrying capacity of homogeneously distributed CNTs.

CVD Grown Materials for High Temperature Electronic Devices : A Review

Abstract: Chemical Vapour Deposition (CVD) remains an extremely popular area of fabricating electronic devices, operating at high temperature and in harsh environments. CVD offers an excellent process controllability and development of quality thin films on varieties of substrates that are compatible to standard IC technology. Plasma enhanced CVD (PECVD), atomic layer CVD (ALCVD), laser CVD and metal organic CVD (MOCVD) need special mention for their added advantages like low substrate temperature, high spatial resolution and precise doping, in addition to the high temperature stability of the films. In this review article, we critically discuss the various standard CVD processes for electronics industry and some high temperature non-oxide ceramic materials like SiC, III-nitrides and carbon nanotubes for electronic device applications. These include optoelectronics devices like laser diode, laser crystal cooling, microwave device, power semiconductor heat spreaders and high temperature pressure and chemical sensors...

Synthesis, Structural Characterization and Thermoluminescence Properties of β-Irradiated Wollastonite Nanophosphor

Abstract: Nanocrystalline wollastonite (?-CaSiO3) phosphor powder has been synthesized by low temperature combustion method and characterized by powder XRD (X-ray diffraction). The structural morphology and the particle size have been analyzed by SEM (scanning electron microscopy) and TEM (transmission electron microscopy) respectively. The powder has been subjected to ?-irradiation and the resulted thermoluminescence (TL) behaviour has been investigated. The TL glow curves reveal that the TL intensity increases with the radiation dose, a property desired by a TL dosimeter. The trapping parameters like activation energy (E) and order of kinetics (b) were estimated by deconvolution method using peak shape of 60 Gy glow curve and the results are discussed. © 2011 The Indian Ceramic Society.

Synthesis of Highly Sinterable Neodymium Ion doped Yttrium Oxide Nanopowders by Microwave Assisted Nitrate-Alanine Gel Combustion

Abstract: Microwave assisted gel combustion synthesis of neodymium doped yttria (Nd:Y2O3) nanopowders using L-alanine complexing agent is being reported. Gelation of metal nitrates with L-alanine followed by combustion in microwave and subsequent calcinations at 1000°C for 3 h under oxygen supply gave phase pure nanopowders characterized by FTIR and XRD. Highly sinterable Nd:Y2O3 nanopowders with size range 20–80 nm, close to spherical and uniform morphology were obtained as observed by TEM compared to particles in size range 40–160 nm, with polyhedral morphology, obtained by sol-gel route. Compaction of calcined powders by cold isostatic press at 400 MPa followed by sintering at 1700°C for 7 h gave ceramic with 26% transmission which increased to 32% after 10 h without any sintering aid for microwave gel combustion compact, compared to 6.7% transmission for sol-gel route compacts. XRD of sintered samples showed retention of phase purity in all the cases. SEM of sintered samples showed good grain fusion for close t...

Effect of Particle Size and Sintering Procedure on Microstructure, Dielectric, Ferroelectric and Mechanical Properties of SrBi4Ti4O15

Abstract: Bismuth layered-perovskite compounds such as SrBi4Ti4O15 (SBTi) ceramics are prepared by solid state reaction. The SBTi ceramics are sintered by microwave and conventional sintering techniques. In this study, the effect of ball milling on different sintering processes, microstructure as well as on dielectric, ferroelectric and mechanical properties of SBTi ceramics is emphasized. The powder has been milled to produce nanocrystalline powders using a planetary ball mill. Different samples have been prepared by varying the milling time from 5 to 20 h, keeping the milling speed fixed at 300 rpm. The X-ray diffraction results show that crystalline powders with a single perovskite structure can be obtained when calcined at 700°C for 4 h. It has been observed that the average grain size, dielectric and ferroelectric properties are dependent on the duration of ball milling. The dielectric constant and loss tangent of the conventional sintered samples range between (140 and 165), and (0.05 and 0.07) respectively a...

Effect of Iron Oxide and Silica Doping on Microstructure, Bandgap and Photocatalytic Properties of Titania by Water-in-Oil Microemulsion Technique

Abstract: The microemulsion method was successfully used to prepare a series of TiO2, Fe oxide and SiO2 doped TiO2 nanoparticles at Fe/Ti atomic ratio of 10% and Si/Ti atomic ratio of 15%. The molar ratio of water to surfactant (W0) was 2. The samples were calcinated at 350°C. The structural features of TiO2, Fe oxide and SiO2-TiO2 were investigated by XRD, UV-Visible spectroscopy, SEM and TEM. XRD data verified the formation of typical characteristic anatase form in all the prepared Fe and SiO2-doped TiO2 samples. In comparison with the pure TiO2, Fe oxide and SiO2-TiO2 samples were relatively large in particle size, indicating that doping with Fe oxide and SiO2 can help in increasing the particle size. The role of SiO2 and Fe oxide doping could be related to the reduction in bandgap of the titania particles; this, in turn, could increase the ability of the particles in absorbing photons with energy in the visible spectrum. The doping of highly stabilized SiO2, Fe oxide in the titania matrix lead to the significan...

Study on the Formation of Crystalline Phases in Lanthanum Borosilicate Glass

Abstract: Glass of composition 40SiO2–20B2O3–30SrO–10La2O3 was prepared by splat quenching techniques. Based on differential thermal analysis (DTA) studies the glass was heated at 900o and 950oC for different time durations. This heat treatment temperature which is nearly operating temperature of solid oxide fuel cell (SOFC) was knowingly selected to determine the nature of crystalline phases present in glass matrix. The as prepared and heat treated glass was characterized by X-ray diffraction technique for its confirmation of glassy structure and crystalline phases, respectively. The microstructural analyses of these heat treated glasses were done using scanning electron microscope (SEM) to study the morphology of crystalline phases. The thermal expansion coefficients (TEC) of glass and glass-ceramics were observed within required limit for SOFC application.

Yttria Dispersion Strengthened Nickel-based Superalloy by Mechanical Alloying

Abstract: Department of Metallurgical Engineering PSG College of Technology Coimbatore – 641 004, Tamil Nadu, IndiaPresent work involves preparation of nano sized yttria dispersed nickel-based superalloy by mechanical alloying (MA) in a planetary ball mill and optimization of process parameters. Nanocrystalline (NC) yttria was synthesized using a simple and economical sol-gel route. Elemental powders of composition Ni-20Cr-3Fe-0.5Ti-0.3Al-0.6Y2O3 wt% were mechanically alloyed at various milling times (5–40 h) in dry milling. Purity of the alloy and phase evolution was characterized by XRD. The alloying behaviour, particle size, particle shape and compositional analysis were done by SEM/EDAX. TEM of MA powders showed grain size in the micrometer range. The powders were consolidated by spark plasma sintering at temperatures from 1173–1373 K and microhardness measurements were also done. The sample sintered at 1173 K had the highest hardness; higher than that reported in the literature.

A Comparative Study of Conventional Sintering with Microwave Sintering of High Dielectric Calcium Copper Titanate Nano Powder Synthesized by Sol-Gel Route

Abstract: Nano-sized calcium copper titanate (CCTO) powder was derived from sol-gel process. Calcium nitrate, copper nitrate and titanium iso-propoxide were used as raw materials. The XRD results of the powder calcined at 800°C indicated the formation of CCTO phase. AFM studies showed that the particle size of the CCTO powder ranged from 70 to 80 nm. The absorption bands corresponding to vibrations of Ca–O, Cu–O and Ti–O–Ti were observed at 606, 525 and 463 cm–1 using FTIR. The samples sintered at 1040°C showed 96% of theoretical density. The dielectric constant of the sample sintered by conventional pressure less sintering was much higher (23,000 at 1 kHz) than that of microwave sintered samples (1572 at 1 kHz). In microwave sintering the grain boundary thickness decreases so that dielectric constant decreases.

Influence of Processing Conditions on the Formation of Y2Ti2O7 and YTiO3 Phases

Abstract: In the present study, the mechanisms for transformation of pyrochlore to perovskite phase (YTiO3), keeping the same initial ingredients and amount of Y2O3 and TiO2, are proposed. The formation of both the phases is correlated using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The microstructure of the sample was examined by scanning electron microscope (SEM). Energy dispersive X-ray spectroscopic (EDX) analysis was carried out to check the stoichiometry of the sample. In addition to this, the morphological behaviour, particularly of YTiO3 phase, is studied so that the formation of both the phases can be correlated to understand the morphology dependent properties of the perovskites and pyrochlore structured materials. The results are discussed in light of disordering caused due to interface controlled growth and reduction of Ti using various characterization techniques.

Sliding Wear Characteristics of Biodegradable Nanocomposites of Cellulose Acetate Phthalate and Chitosan Reinforced with Functionalized Nanoclay

Abstract: Cellulose and chitosan are two of the most abundant naturally occurring substances which are being increasingly used for developing biodegradable polymer composites given the current environmental ...

Comparative Humidity-Sensitive Behaviour of Undoped and Acceptor-doped Barium Stannates

Abstract: Three samples, undoped barium stannate (BS), 10 atom% nickel-doped barium stannate (BSN10) and 10 atom% chromium-doped barium stannate (BSC10) were synthesized via solid state reaction route. The formation of single phase of these samples was confirmed by powder X-ray diffraction pattern analysis. These samples have a cubic crystal structure. The lattice parameter of samples BS and BSN10 are nearly the same, whereas that of sample BSC10 is smaller. The bulk density and grain size of the samples are in the order BSN10 > BS > BSC10 and BSC10 > BSN10 > BS, respectively. The resistance and capacitance of the samples at room temperature (31°C) were measured in the frequency range of 20 Hz - 1 MHz and the relative humidity (RH) range of 10–95%. Amongst these three samples, sample BS exhibits a superior response to humidity. The resistance of this sample changes by more than three orders of magnitude as RH changes from 10 to 95%. The response and recovery times of the samples BSC10 and BS are nearly the same (fo...

Surface Morphology and Dielectric Behaviour of Gd-Doped Ba(Zr0.52Ti0.48)O3 Nanocrystalline Ceramics

Abstract: Surface analysis, frequency dependent permittivity, impedance and ac conductivity studies of gadolinium (Gd) doped BZT perovskite ceramics having stoichiometry (Ba1–xGdx)(Zr0.52Ti0.48)O3 (x = 0.1 and 0.2) were reported. Surface morphology including grain distribution, histogram of area, volume, length and perimeter was examined through atomic force microscope. Surface morphological images showed non-uniform distribution of grains. These compounds exhibited abnormal dielectric losses in the frequency range of 10 kHz to 1 MHz. Anomalous variation in frequency dependent relative permittivity (ϵʹ) behaved as non linear dielectric materials with interesting properties. Substitution of Gd ion in BZT resulted in significant lattice distortion due to strain imported via doping. This distortion caused low impedance which in turn increased the magnitude of ac conductivity.

Catalytic Cracking using Nanoporous AlMCM-41 for the Production of Green Fuel

Abstract: The depletion and environmental degradation of fossil fuels are the main concerns of today's researchers. This has triggered the interest of researchers to find alternative fuels. Any alternative fuel should be sustainable, greener and cost effective. Biofuel derived from non edible oil crops will be an ideal choice as it satisfies the above requirements. Among the various non edible oil crops grown all over the world, jatropha oil has drawn much attention of researchers to produce an alternative fuel free from sulphur and nitrogen. In the present study catalytic cracking technology is used to produce green fuel. Herein we report the synthesis of nano AlMCM-41 along with its characterization by XRD, BET surface area analyzer, inductively coupled plasma (ICP) spectrometer, and also its ability towards cracking of jatropha oil using fixed bed flow reactor at optimized conditions. Among the nanoporous AlMCM-41 with different Si/Al ratios (Si/Al = 25, 50, 75 and 100), AlMCM-41 (Si/Al = 25) has been found to b...

Ionic to electronic conductivity studies of lithium-borate ruby-glass-ceramics containing gold nano particles

Abstract: Glass-​ceramics contg. Au nanoparticles have been synthesized in the glass compn. 30Li2O-​70B2O3 with HAuCl4.3H2O as dopant. The characteristic ruby color has been obsd. which is attributed to the surface plasmon resonance of the Au nanoparticles, uniformly embedded in the glass matrix. The imparted red color due to the presence of gold nanoparticles has been confirmed by studying the optical absorption spectra using UV-​VIS spectrometer in the visible range (400-​1000 nm) which show a characteristic absorption peak at ∼560 nm. In order to check the crystn.​/amorphous nature, the samples were powd. and characterized using X-​ray diffraction (XRD)​. The microstructural modifications in the samples due to the addn. of Au have been recorded using SEM (SEM)​. Further, the ESR (ESR) studies reveal that the electronic state of gold is either Au0 or Au+. AC cond. studies have been performed at room temp. over a frequency range 100 to 10 MHz. The ac cond. data is fitted by Almond-​West law with power exponent "s". The dc cond. is found to be increasing with the increase of temp. for a typical ruby glass, but almost const. with dopant concn.