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The present work reports the very first observations on initiation of nanoscale plastic events in 20 ZTA (Zirconia Toughened Alumina) ceramics. The nanomechanical properties as well as the intrinsic contact deformation resistance of the present ZTA ceramic are studied here as a function of low loads (i.e., 10–1000 mN). Here we report for the very first time, the detailed mechanisms on the genesis of ‘micro pop-in’ events that characterize the nanoscale plasticity initiation in the 20 ZTA ceramics. These new results along with field emission scanning electron microscopy (FESEM) based evidences confirm that the combined contributions from the maximum shear stress generated underneath the nanoindenter, the formations of shear bands and localized microcracking play significant roles in the initiation of nanoscale plastic events in the 20 ZTA ceramics.

Here we report for the very first time, the detailed mechanisms of the formation of ‘micro pop-in’ events observed during nanoindentation at 10–1000 mN load in a 10 ZTA (i.e., 10 vol% zirconia toughened alumina) ceramic. Explicit analysis of the experimental results backed up by comprehensive Field Emission Scanning Electron Microscopy (FESEM) based evidences suggests that the maximum shear stress (τmax) generated underneath the nanoindenter, the formations of shear bands and localized microcrackings play significant role in the initiation of nanoscale plastic events in the present ZTA ceramic.

Here we report for the first time the time-dependent mechanisms of self assembly and growth of Mg(OH)2 nanoparticles. For this purpose, the nanopowders are obtained by a simple chemical precipitation route. To understand the route map of the growth process; the nanopowders are subsequently characterized by XRD, FTIR, BET, pore size distribution, FESEM and TEM analysis techniques. Based on the results obtained from aforesaid characterizations the mechanisms of self-assembly and nanoplatelets growth process as a function of reaction time are explained.

Methylene blue (MB) dye present in industrial wastewater is a well-known carcinogenic source. By utilizing phase pure three dimensional self assembly of magnesium hydroxide nanoparticle (3DSAMHNPs)...

It is well known that physical, structural, mechanical as well as other functional properties change drastically at the nanoscale, thereby giving rise to size effects in all materials, especially ceramics. Therefore, it is extremely relevant today to understand the basic scientific issues involved in the development of size effects in materials, particularly ceramics which are characteristically brittle in nature. Hence, to be able to design better contact resistant ceramics; it is of significant importance to understand the genesis of indentation size effect (ISE) in the nanomechanical response of structural ceramics like zirconia toughened alumina (ZTA). Here we report the first-ever systematic study on ISE in nanoindentation behavior of 10, 20 and 40 volume% (vol%) ZTA. The nanoindentation experiments were conducted at an ultra low load range of 1–1000 mN. As the experimental data showed the presence of strong ISE, the efficacies of existing models in explaining the same; were critically examined. Among existing models, the strain gradient plasticity model provided the real physical reason for the genesis of ISE in ZTA and hence, explained the data the best. Similarly, existing models were used to predict the variations in experimentally measured ratios of plastic to total energy spent in the nanoindentation process. The results showed that the Malzbender model predicted experimental data the best. This observation implied the best efficacy of the internally expanded cavity concept in explaining the nanoindentation response of the present ZTA ceramics. In addition, the other possible mechanisms of ISE in ZTA were discussed. Finally, the linkage of microstructural parameters to ISE in ZTA was explored.

A scalable, cost effective synthesis of reduced graphene oxide (RGO)-magnesium oxide (MgO) hybrid nanocomposite (RGOMOHNC) is reported in the present work. The process involves an in-situ sonication method in aqueous medium at room temperature e.g., 30 °C. The as synthesized graphene oxide (GO) and RGOMOHNC powders are characterized by the XRD, FESEM, TEM, FTIR, RS and XPS techniques. The results indicate that in-situ growth of 20–30 nm MgO nanoparticles effectively increases the graphitic nature of the layered RGO microstructure. The experimentally measured cyclic voltammetry (CV) plots show that the specific capacitance of the RGOMOHNC powders is three orders of magnitude higher than that of the GO powders. A mechanism of RGOMOHNC formation has been proposed.

Au nanoparticle (NP)-decorated titanium dioxide (TiO2) thin films (Au-TO), prepared by a unique surfactant-assisted 2D self-assembling technique of Au NP layering onto a titanium dioxide matrix (TO) with molecular-level control, in conjunction with a classic sol–gel route, showed a significant decrease in the optical band gap (ΔEg = ∼0.6 eV) of Au-TO films compared to the conventional sol–gel-prepared pristine counterpart. Strong dependence on surfactant type and deposition temperature of the 2D Au NP layer was observed upon a band gap decrease of the films. Unlike spin-coated Au NP overlayers on TiO2, which resulted in Au NP agglomeration, in this modified inverted Langmuir–Schaefer (MILS) technique, the organic surfactant induced 2D patterned confinement of Au NP layers on TiO2, causing an increase in the active surface area of the Au NP–TiO2 interface. Results of X-ray diffraction and near-edge X-ray absorption fine structure spectroscopy indicated changes in crystal structure as well as in electronic ...

This chapter focusses on how the microstructurally engineered ceramics can be successfully used for environmental applications, e.g., in development of materials that can be used for treatment of industrial wastewater. Industrial wastewater comes from mainly iron and steel industries, textile, and leather industries, as well as paper and pulp industries. Other contributors to this scenario are non-ferrous metals, chemicals, mining, petrochemicals, and refineries. Microelectronics as well as the pharmaceutical industries also contribute. It is well known that industrial wastewater contains toxic ions and dyes. When such contents cross the permissible limit it may become an issue of major environmental concern. The present work demonstrates that by using the microstructurally designed, phase pure Mg(OH)2 nanoplatelets 99.99% adsorption of the toxic Cu(II) ion can be achieved. Further, it is shown that phase pure micro-dumbbell shaped three dimensional, self-assembly of Mg(OH)2 nanoplatelets can degrade MB dye with 98% efficacy. The mechanisms behind such extraordinary capabilities of engineered nanoceramics are discussed. The implications of such developments for futuristic industrial wastewater treatment is also focused on.

The soft chemical synthesis of self-assembled magnesium hydroxide (Mg(OH)2) nanoplatelets with surface area as high as about 300 m2 g−1 was achieved in the present work. The nanopowders such as MHN, MHCl, MHBr were synthesized at ~30 °C without using any catalyst or surfactant using, respectively, precursor solutions of Mg(NO3)2, MgCl2, MgBr2 and characterized by XRD, BET surface area, BJH pore size analysis, FTIR, FE-SEM, TEM and EDX techniques. It was found that the MHN and MHCl nanopowders comprised of nanoflowers formed by self-assembly of nanoplatelets and porous nanoplatelets, while the MHBr nanopowders comprised of a random assembly of nanocapsules. The powders possessed the technologically important quality of reproducible CO2 adsorption at room temperature and its desorption at a relatively lower temperature of 75 °C. Based on the experimental evidences, the mechanisms of various microstructure formations and CO2 adsorption mechanism were also proposed.

Here we report for the very first time a simple, inexpensive, room temperature synthesis method of formation of mixed calcite–calcium oxide nanojasmines (CTCaONJs). The method involves chemical precipitation in aqueous medium at room temperature in open atmosphere in order to allow natural carbonation to occur. Aqueous solutions of calcium nitrate dihydrate (Ca(NO 3 ) 2 ·2H 2 O) and sodium hydroxide are used as precursors. The nanopowder is characterized by the Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX), BET (Brunauer–Emmett–Teller), BJH (Barrett–Joyner–Halenda) techniques. Optical properties of nanojasmines (NJs) were investigated by UV–vis spectroscopy. The powder has calcite as the major phase and calcium oxide as the minor phase. The crystallite size of calcite along (104) crystallographic direction is about 18 nm with a size strain of about 1.03%. The high (e.g., 8.8 m 2 g −1 ) surface area powder exhibits a mesoporous microstructure with 5–15 nm pore size. Further, it possesses a relatively higher optical band gap of 5.87 eV. The FESEM and TEM based evidences show that the CTCaONJ flowers mainly comprise of nanoplatelets made up of irregular nanorods and nanowires consisting of amorphous spherical nanoparticles. Based on these experimental evidences a qualitative model is proposed to explain the growth mechanism of the CTCaONJ flowers.

The present work reports a simple, inexpensive method for synthesis of calcium hydroxide Ca(OH)(2)] nanoparticles (CHNPs). The method involves chemical precipitation (CP) in aqueous medium at room temperature. Calcium nitrate dihydrate Ca(NO3)(2).2H(2)O] and sodium hydroxide were used as precursors. The CHNPs were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Rietveld analysis, field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), BET surface area evaluation as well as particle size distribution analysis techniques. The results confirmed the synthesis of CHNPs as the major phase. The CHNPs exhibited an average size of about 350 nm. In addition, some calcite phase formed due to the inevitable carbonation process. A very minor amount of aragonite phase was also present. A schematically developed new qualitative model is proposed to explain the genesis and subsequent evolution of the various phases at the nanoscale. The model helps to identify the rate-controlling step. It also highlights the implication of reaction kinetics control in synthesis of predesigned nanophase assembly.

Here we report the efficacy of the photoluminescence (PL) spectroscopy for novel detection of as low as 0.0001 to as high as 0.01 ppm of Cd2+ and Pb2+ ions in simulated wastewater solution. The solution comprises of 20 mg of layered graphene oxide (GO)-Mg(OH)2 nanocomposite (LGOMHNC) powders in 100 ml of DI water. The LGOMHNC powders, synthesized by facile wet chemical route, are characterized by XRD, FESEM, TEM, FTIR, Raman spectroscopy, TGA-DTA, XPS and especially, the PL spectroscopy techniques. After adsorption of Cd2+ and Pb2+ ions, the novel LGOMHNC powders exhibit significant enhancement of the corresponding PL intensities as compared to those of the as-synthesized LGOMHNC powders. These results suggest that PL spectroscopy can indeed emerge as a very important tool for detection of even 0.0001 ppm of Cd2+ and Pb2+ ions in simulated wastewater. In addition, the novel LGOMHNC powders developed in the present work can have huge application potential in futuristic, optical sensor-based detection of the toxic, heavy metal ions like Cd2+ and Pb2+.

The intertwined nanopetal assembly of Mg(OH)(2) powder was synthesized in the present work by a very simple, inexpensive, green chemical route without using any catalysts and templates. The synthesized powder was thoroughly investigated by X-ray diffraction, BET and BJH measurements, Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, thermo-gravimetric and differential thermal analysis techniques. The results showed that phase pure, oxygen rich Mg(OH)(2) powder of 2.7-6.16 nm crystallite size, similar to 7 nm pore size, and similar to 93.76 m(2) gm(-1) surface area was obtained. Finally, the possible growth mechanism of intertwined nanopetal assembly was discussed for the Mg(OH)(2) powders. (c) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Here, we report for the first time ever the catalyst free growth of magnesium oxide (MgO) nanoribbons on soda lime silica glass substrates by a green and inexpensive chemical route. The MgO nanoribbons were grown when the precursor magnesium hydroxide (Mg(OH) 2 ) thin films were converted to MgO after 2 h of heat treatment in air at 450 °C. The MgO thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and the related energy dispersive X-ray spectroscopy (EDAX) techniques. Finally, a plausible mechanism is suggested for growth of the MgO nanoribbons.

The present work reports the in situ formation of nanostructured magnesium hydroxide thin film by an inexpensive and simple chemical deposition technique on commercially available soda lime silica glass substrates at room temperature. The structural characterizations of the thin films were done by X-ray diffraction as well as thermo-gravimetric and differential thermal analyses. A detailed study of the microstructure by scanning electron microscopy, field-emission scanning electron microscopy and transmission electron microscopy revealed the formation of magnesium hydroxide nanorods. The condition that favours the growth of the nanorods was identified.

Presence of both Cd(II) and Pb(II) ions in water is highly toxic for human health. That is why WHO recommends maximum permissible values of cadmium and lead in drinking water as 0.003 mg.L-1 and 0.01 mg.L-1, respectively. Therefore, here we report for the first time the adsorption kinetics of Mg(OH)(2) for adsorptions of Pb(II) and Cd(II). To the best of our knowledge, this is the very first attempt to evaluate the Langmuir and Freundlich isotherms of Mg(OH)(2) nanostructures with different morphologies for adsorptions of Pb(II) and Cd(II). The changes in adsorption processes with temperature are also studied. The Mg(OH)(2) nanostructures reduce the concentration of Cd(II) ions from as high as 1000 mg.L-1 to as low as 0.001 mg.L-1 and that of Pb(II) ions from as high as 1000 mg.L-1 to as low as 0.009 mg.L-1 . These values are much lower than the permissible limits prescribed by WHO. To attain these very significant achievements the time dependent changes in pore size, pore size distribution and surface area are explored. Finally, the results obtained by XRD, FTIR, Raman, pore size, pore size distribution, BET surface area, FESEM, TEM, EDX and adsoption kinetics studies show that nanoplatelet Mg(OH)(2) powders exhibit the highest respective adsorption efficacies of 3700 mg.g(-1) and 3030 mg.g(-1) for Pb(II) and Cd(II). Thus, the nanoplatelet Mg(OH)(2) powders may possibly find huge usage in near future for water purification applications.

Here we report the first ever studies on nanomechanical properties e.g., nanohardness and Young׳s modulus for human hair of Indian origin. Three types of hair samples e.g., virgin hair samples (VH), bleached hair samples (BH) and Fe-tannin complex colour treated hair samples (FT) with the treatment by a proprietary hair care product are used in the present work. The proprietary hair care product involves a Fe-salt based formulation. The hair samples are characterized by optical microscopy, atomic force microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy (EDAX) genesis line map, EDAX spot mapping, nanoindentation, tensile fracture, and X-ray diffraction techniques. The nanoindentation studies are conducted on the cross-sections of the VH, BH and FT hair samples. The results prove that the nanomechanical properties e.g., nanohardness and Young׳s modulus are sensitive to measurement location e.g., cortex or medulla and presence or absence of the chemical treatment. Additional results obtained from the tensile fracture experiments establish that the trends reflected from the evaluations of the nanomechanical properties are general enough to hold good. Based on these observations a schematic model is developed. The model explains the present results in a qualitative yet satisfactory manner.

The present work reports the utilization of a relatively simple, cost effective sol-gel technique based route to synthesize highly transparent, spin coated 4.1 at% Al+3 doped MgO thin films on quartz substrates. The films were characterized by XRD, XPS, Raman spectroscopy, and SIMS techniques. The microstructures were characterized by FESEM and TEM while the nanomechanical properties were assessed by the nanoindentation technique. Finally the optical transmittance was measured by UV-vis technique. The x-ray diffraction (XRD) study suggests the crystal facet (2 0 0) of MgO lattice to be distorted after incorporation of Al+3 into MgO lattice. From FESEM the doped films were found to have a dense microstructure with a crystallite size of about 20 nm as revealed by the TEM studies. Nanoindentation measurements indicated drastic increase of elastic modulus for the Al+3 doped MgO thin films by similar to 73% compared to that of the pristine MgO thin films along with retaining the nanohardness at similar to 8 GPa. The transmittance of Al+3 doped MgO thin films in the visible range was significantly higher (similar to 99%) than that of pristine MgO (similar to 90%) thin films. The films also had a relatively higher refractive index of about 1.45 as evaluated from the optical properties. The enhanced transmittance as well as the improved elastic modulus of Al+3 doped MgO thin films suggest its promising candidature in magnetic memory devices and as buffer layers of solar cells.

The present work examined the efficacy of designed Mg(OH)(2) nano-platelet assembly (DMGHNPA) for toxic Cu(II) waste removal from water. For this purpose, DMGHNPA with surface area as high as 237 m(2).g(-1) was synthesized by a very simple and cost effective method at room temperature. The results showed that at concentration range of 80-1000 mg.l(-1), extra-ordinarily high e.g. > 99% Cu(II) ion adsorption efficacy was achieved by the DMGHNPA. Based on the experimental data, adsorption mechanism is proposed to explain the extra-ordinary high adsorption efficacy of the DMGHNPA. The efficient adsorption was occurred through Cu-2(NO3)(OH)(3) microspheres formation on the surfaces of self-supported DMGHNPA. The implication of such extra-ordinary high adsorption efficacy of the Mg(OH)(2) nano-platelet assembly is discussed further in the context of toxic waste e.g. Cu(II) ion removal from water.

Here we report two qualitative models on failure and deformation mechanisms at macro- and nano-scales of alkali activated clay (AACL), a material of extraordinary importance as a low cost building material. The models were based on experimental data of compressive failure and nanoindentation response of the AACL materials. A 420% improvement in compressive strength (sigma(c)) of the AACL was achieved after 28 days (d) of curing at room temperature and it correlated well with the decrements in the residual alkali and pH concentrations with the increase in curing time. Based on extensive post-mortem FE-SEM examinations, a schematic model for the compressive failure mechanism of AACL was proposed. In addition, the nanoindentation results of AACL provided the first ever experimental evidence of the presence of nano-scale plasticity and a nano-scale contact deformation resistance that increased with the applied load. These results meant the development of a unique strain tolerant microstructure in the AACL of Indian origin. The implications of these new observations were discussed in terms of a qualitative model based on the deformation of layered clay structure.

Here we report the synthesis of V2O5 nanostructures by a fast, simple, cost-effective, low-temperature chemical process; followed by the deposition of V2O5 xerogel thin films on a glass substrate by a sol-gel route. Phase analysis, phase transition, microstructural and electronic characterization studies are carried out by x-ray diffraction, texture coefficient analysis, field emission scanning electron microscopy, transmission electron microscopy (TEM), related selected area electron diffraction pattern (SAED) analysis, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, and x-ray photoelectron spectroscopy techniques. Confirmatory TEM and SAED data analysis prove further that in this polycrystalline powder there is a unique localized existence of purely single crystalline V2O5 powder with a preferred orientation in the (0 1 0) direction. The most interesting result obtained in the present work is that the xerogel thin films exhibit an inherent capability to enhance the intrinsic resistance against contact induced deformations as more external load is applied during the nanoindentation experiments. In addition, both the nanohardness and Young's modulus of the films are found to be insensitive to load variations (e.g. 1 to 7 mN). These results are explained in terms of microstructural parameters, e.g. porosity and structural configuration.

The inexpensive and green method of synthesis for self-assembled micro/nano structures is an important area of emerging research. Such structures can be chemically tuned with predesigned functional properties. Therefore, they hold very good promise for future applications, e.g., biomedicine, electronic device, solar energy, gas sensing. Here we report for the first time an inexpensive and green method for chemical deposition of magnesium hydroxide (Mg(OH)2) micro/nano flowers in thin films on commercial soda lime silica glass substrates at room temperature. Under identical conditions, chemically synthesized Mg(OH)2 powders are also prepared in absence of the soda lime silica glass substrates. The condition that favors the growth of micro/nano flowers in thin films is identified from X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) data. Finally, the possible growth mechanism of micro/nano flowers in thin films is discussed.