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Sputter grown copper (Cu) and titanium dioxide (TiO2) based transparent solar heat rejecting film has been developed on glass substrates at room temperature for energy saving smart window applications. The performance of as-deposited ultra-thin TiO2/Cu/TiO2 multilayers was elucidated, wherein the visible transmittance of the multilayer significantly depends on the crystal quality of TiO2 layers. In-situ nanocrystal engineering of TiO2 films with optimized sputtering power improves crystallinity of nano-TiO2 domains. The transparent heat regulation (THR) coating with an average transmittance of ∼70% over the visible spectral regime and infra-red reflectance of ∼60% at 1200 nm was developed at room temperature. Optical characterization, X-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM) and atomic force microscopy (AFM) have been utilized to analyze the crystallinity of TiO2 and quality of the multilayered structure. TiO2/Cu/TiO2 based prototype device has been demonstrated for the energy saving smart windows application.

Magnesium aluminate spinel with an initial MgO: Al2O3 molar ratio of 2:1 was prepared from its constituent oxides through a solid-state sintering process at temperatures ranging from 1550 to 1700 °C in a normal air atmosphere. The effect of varying amount (0.25–1.0 wt%) of TiO2 and Yb2O3 on densification, phase assemblage, mechanical, thermo-mechanical properties and microstructure of magnesia-rich spinel were investigated under static heating condition. The addition of TiO2 and Yb2O3 favours the densification of magnesia-rich spinel, which is discernible up to 1650 °C. This beneficial effect may be attributed to the development of the secondary phase and formation of solid solution due to the dissolution of the additive ions in the spinel structure. A marginal increase in the average grain size of the samples along with a narrower grain size distribution occurred with the incorporation of both the additives. Both the additives improved the mechanical properties of the magnesia-rich spinel; however, better room temperature flexural strength was achieved with Yb2O3 as compared to TiO2 addition. For the samples sintered at 1550 °C, 1.0 wt% Yb2O3 addition resulted in 30% increase in flexural strength; however, same amount of TiO2 addition increased the strength by 20%. In case of thermal shock resistance, 1.0 wt% TiO2 and 0.25 wt% Yb2O3 addition demonstrated promising result among all the samples.

Nano-scale load (P) dependency of fracture toughness (K1C) of indium tin oxide (ITO) coating on silicon (Si) substrate is evaluated by nanoindentation based direct and energy methods. A Berkovich triangular diamond nanoindenter is used with nine different P values e.g., 10, 15, 20, 30, 40, 50, 100, 150 and 200 mN. Extensive utilization of both optical microscopy (OM) and field emission scanning electron microscopy (FESEM) techniques reveal that up to P ≤ 40 mN only the sharp radial cracks form from three corners of the nanoindent. However, for P > 40 mN, multiple cracks occur over and above the radial cracks. Finally, at P: 150–200 mN coating gets chipped off from the substrate. The K1C values of the ITO coating are calculated on the basis of both the conventional radial crack length measurement based method and the strain energy release based method. The K1C values are strongly sensitive to variations in P. Further, the strain energy method results in higher magnitudes of the K1C values.

It is well known that graphene (G), graphene oxide (GO) and reduced graphene oxides (RGO) are materials of today with immense application potentials. However, to realize the same large scale, reproducible, sustainable synthesis techniques such as greener methods which avoid utilization of toxic chemicals for synthesis, must be adopted. It is in this context, that here we report the reduction of GO to RGO by the extract of Thuja Orientalis (TO) seeds. As such, TO is a well-known bio-resource for medicinal and various other biotechnological applications as it contains Alpha Tocopherol, the major constituent of vitamin E. To the best of our knowledge, despite the wealth of literature, the current work makes a pioneering effort in applying TO seeds extract for reduction of GO to RGO. Thus, the reduction of GO, synthesized by the well-known modified Hummer's method to RGO by TO extract, is confirmed from the results obtained by ultra-violet visible (UV–Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) analysis, selected area electron diffraction (SAED), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and especially, gas chromatograph mass spectrometry (GCMS) techniques. Furthermore, the GCMS study is used to identify the compound Alpha Tocopherol responsible for reduction of GO to RGO. Based on current experimental evidences and literature views, the possible mechanism of reduction is suggested. Finally, the implications of present studies in the perspective of large scale, sustainable synthesis of RGO for various technological applications are discussed.

A major problem with femoral head (FH) for hip implant (HI) applications is that it often fails in service. As a result, revision surgery becomes a must. The related trauma is tremendous for the patient, especially the aged ones. This also implies additional expenses. Keeping these aspects of the problem in view, here we report the development of wear, corrosion and fatigue resistant Ti6Al4V alloy based FH; by a duplex surface engineering (DSE) technique. Thus, the DSE based FHs are developed by a novel combination of plasma nitriding (PN) and Ti/TiN multilayer coating (MLC). The MLCs are formed by magnetron sputtering technique. The Ti6Al4V based FHs are called Ti. The only plasma nitrided FHs are called TiPN. The DSE based FHs are called TiPNML. The corrosion resistances are studied in hank's solution. The sliding wear resistance is studied in simulated body fluid (SBF). The biocompatibilities are studied by the standard MTT assay technique. The cyclic fatigue resistance behaviour up to one million walking cycles is studied in SBF in a HIP simulator with the UHMWPE acetabular cups used as the counter bodies in articulation. The results of the corrosion, biocompatibility, wear, and cyclic fatigue resposnses clearly reveal that the performances of the TiPNML and TiPN FHs are much better than that of the Ti based FHs. The reasons behind such spectacular improvement in biocompatibility as well as corrosion, wear and fatigue resistance are explained in terms of the prevalent phases, microstructural factors, wear mechanisms and surface roughness. The implications of the current results in terms of futuristic FH developments for HI applications are discussed. Such futuristic FH development could provide better HI. These prospects would minimize HI failure and hence, revision surgeries. Thus, the related trauma for numerous patients; especially the aged ones; could be significantly reduced.

Effect of Silver (Ag) doping in shaping magnetic properties of sol-gel derived TiO2 nanoparticles (NPs) is studied using different characterisation techniques. An interconnection between the results of characterizations and the magnetic behavior of the Ag doped samples has been established. XRD patterns show an anatase to rutile phase transition in NPs at 14 at. % Ag doping. XRD peaks related to metallic Ag are found in the TiO2 NPs containing 10 and 14 at. % Ag whereas secondary phase of Ag2O is noticed in all the samples. FESEM images exhibit the presence of segregated silver clusters attached to the TiO2 nanostructures for 10 and 14 at. % Ag doping. XPS detects the presence of several cationic states in doped TiO2 NPs. UV–Vis measurements reveal that the quantum size effect enhances the band gap at initial level of doping and afterwards it continiously decreases due to sp-d exchange interactions. M − H study shows the emergence of soft ferromagnetism (FM) in the sample doped with a critical Ag+ ion concentration of 5 at. % due to d-orbital mediated spin information transfer between two hole trapped Ag+ ion and a Ti3+ defect leading to the formation of BMP. Temperature dependent FC and ZFC magnetization measurements indicate coexistence of ferromagnetic and antiferromagnetic domains. The investigations culminate in identification of not only the optimum processing conditions for enhanced FM properties along with good physical characteristics but also the probable cause behind the origin of FM in Ag doped TiO2 NPs. Such Ag doped TiO2 NPs can be useful for development of futuristic spintronic and magneto-optical devices.

The thermal conductivity of the matrix part of alumina – carbon unshaped refractory has been estimated to accurately interpret its thermophysical and thermomechanical behavior. The properties of precalcined composite matrix containing either as-received or surface-modified graphite in equal quantity (20.0 wt%) have been investigated at three different temperatures (110,550,900 °C). The thermal compatibility or degradation of both kinds of carbonaceous matrices had been correlated with respective scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analyses. The monolithic matrices were also subjected to X-ray diffraction (XRD) studies to distinguish between their phase evolution patterns. A synergestic study on an equivalent graphite-free formulation was also carried out. The thermal shock resistance profile of respective castables had been addressed to confirm the superiority of surface-treated graphites. Nanoengineering at graphite surface was conceived by Rietveld analysis of the (004) peak that substantiated the additional influence of calcium aluminate coating on selective clumping and partial exfoliation of graphite sheets.

Carbon nanotube (CNT) reinforced bulk ceramic composites are not considered suitable for engineering applications involving exposure to temperatures beyond ~500 °C in air due to oxidation of the reinforcing CNTs. Against this backdrop, we report here the development of bulk Al2O3-CNT composites that are resistant to oxidation induced degradations at high temperatures in air and are also inherently very ‘strong/tough’. SiC-coated multi-walled CNTs (MWCNTs), developed via scalable low temperature route, were incorporated into Al2O3 matrix via an innovative route, which leads to inter- and intra-granular reinforcement of the sintered polycrystalline matrix by the MWCNTs. Such Al2O3-(SiC-coated)MWCNT composites possess enhanced resistance to indentation-induced crack propagation and flexural strength by ~41 and ~50%, respectively, with respect to monolithic Al2O3; along with improvement in the abrasive wear resistance by ~54%. This, in a way, re-confirms the structural compatibility of the SiC-coated MWCNTs with the Al2O3 matrix. In the context of oxidation, the Al2O3-MWCNT composite counterparts, having uncoated MWCNTs, suffered from nearly complete loss of MWCNTs upon exposure to air at 1000 °C (for 1 h), with concomitant reduction in density and reverting back of the fracture mode from transgranular to intergranular (as for monolithic Al2O3). By contrast, the Al2O3-(SiC-coated)MWCNT composites did not suffer from any such oxidation-induced loss/degradation even up to 1000 °C in air.

Here we report for the very first time the intelligent, novel design and synthesis, microstructural, optical as well as nanomechanical characterization of a multilayer ceramic polymer microcomposite (MLCPMC) structure comprising of a spin coated PEDOT:PSSlayer sandwiched between two spin coated TiO2 layers. The results show that in comparison to the nanomechanical properties of the polymeric PEDOT:PSS layer, spectacular improvement in nanomechanical properties is achieved in the MLCPMC structure. In addition, excellent optical tunability is achieved in the MLCPMC structures, without compromising the transmittance in the visible range. Thus, the novel MLCPMC structure may provide a further step towards materials for flexible electronics with additional benefit of extraordinary mechanical integrity. These results are discussed in terms of low temperature phase and microstructure development. Further, the mechanism of spectacular improvement in nanomechanical properties is proposed. Finally, the implications of these unique results for development of intelligently designed multilayered micro/nano composite structures for multifunctional applications in various domains such as strategic, space, military, structural, bio-sensing, OLED devices, DSSCs, flexible electronics and bioelectronic applications; are discussed.

To develop TiB2–TiN–SiC and TiB2–TiN–SiC-hBN based ceramic matrix composite coatings with superior mechanical and tribological properties suitable for engineering applications, a high-power CW-laser is used to initiate chemical reactions in precursor powder mixtures (TiO2, SiO2, hBN and graphite) of several compositions preplaced over AISI1025 steel substrates. Here, coatings’ stoichiometric compositions (TiB2–TiN–SiC) fabricated through in-situ synthesis are altered by adding SiC and additional amount hBN in the precursor at variable weight ratios. Presence of variable amount of SiC in TiB2–TiN–SiC and hBN in TiB2–TiN–SiC-hBN composites imparts several microstructural, mechanical and tribological property combinations. In this study, an attempt has been made to experimentally evaluate the optimum range of hBN and SiC additions to obtain highest improvements in lubrication and wear resistance respectively.

The ceramic nanocomposites (CNCs) like zirconia toughened alumina (ZTA) ceramics are important futuristic materials for structural and functional applications in advanced strategic systems, structural components, biomedical prostheses and devices. In all structural materials including the ZTA CNCs, the very early stages of plastic deformation i.e., the incipient plasticity events (IPE) are most important to be understood so that the microstructure and mechanical properties can be tuned to suit a given end application. Here we report for the first time the mechanisms of IPE in the nanoindentation experiments conducted at 10–1000 mN loads in the 40 ZTA CNCs. Here 40 ZTA CNC stands for 40 vol% of 3 mol% Yttria partially stabilized zirconia toughened alumina (40ZTA) CNC. The role of load ranges in variations of the IPE related parameters in the 40 ZTA CNCs is also studied. Further, an attempt is made to assess how the amount of zirconia content in ZTA CNCs affects the variations of the IPE related parameters. Through the extensive usage of field emission scanning electron microscopy (FESEM) and theoretical estimations, efforts are also directed to check out the linkage, if any, between the localized shear deformation and/or microcracking with the IPE events that occur in the present CNCs. In addition, a new concept of damage resistance is introduced for the first time in the present work to explain the presence of a strong indentation size effect (ISE) in the 40 ZTA CNCs. Finally, an attempt is also directed to understand how the indentation load (P) controls the relative size of interaction zones of dislocation loops as well as the damage resistance and thereby, engineer the acuteness of the ISE in ZTA CNCs. The implication of these findings in futuristic design of especially the ZTA CNCs for various applications is also discussed.