In2O3 Particles Research Articles

Hydrogen plasma reduction induced oxygen vacancies in cubic In2O3 particles with enhanced photocatalytic performance

The impacts of oxygen vacancies on the photocatalytic performance of In2O3 particles were never investigated previously. In this paper, cubic shape In2O3 particles were synthesized by hydrothermal method, and different concentrations of oxygen vacancies were generated in In2O3 particles by controlling the H2 gas flow rate in hydrogen plasma reduction. The SEM images confirmed that the hydrogen plasma reduction did not change the particle morphology. The existence of oxygen vacancies was determined by electron paramagnetic resonance spectrum. Finally, the photocatalytic performance of In2O3 particles with different concentration of oxygen vacancies was investigated by the degradation of Methylene Blue (MB) solution under visible light irradiation. It was observed that when the hydrogen flow rate is 2 mL/min, the sample showed the highest photocatalytic performance, a further increased flow rate resulted in a decreased photocatalytic performance, which could be attributed to the over reduction of In2O3.

Preparation of In(OH)3 and In2O3 Nanorods through a Novel Hydrothermal Method and the Effect of Sn Dopant on Crystal Structures

Indium hydroxide (In(OH)3) nanorods and Sn-doped indium oxyhydroxide (InOOH) nanoparticles were synthesized through the hydrothermal method in an aqueous solution. Sodium hydroxide (NaOH) was introduced to adjust the pH value, and sodium acetate (CH3COONa) was employed as the inducer to accelerate the growth along the preferential orientation. Cubic In(OH)3 was synthesized at pH values ranging from 4.0 to 8.0. In(OH)3 nuclei grows in the direction {100} into nanorods observed from lattice fringes with an interplanar spacing of about 0.403 nm. The SAED pattern of In(OH)3 nanorods indicates the rodlike nanocrystal is a single crystal which matches well with the characteristic peaks of cubic In(OH)3 XRD patterns. The FTIR spectrum signifies the absorption of CH3COO– onto the surface of In(OH)3 nanorods, which accelerate the growth along the direction {100}. Due to the inhibition effect of OH–, In(OH)3 particles with a smaller aspect ratio and In2O3 particles with a smaller crystal size were synthesized with ...

Ultrahigh sensitivity and selectivity chlorine gas sensing of In2O3 hollow microtubules by bio-template method with degreasing cotton

A simple two-stage procedure of immersion-calcination method has been developed for preparing In2O3 hollow microtubules by using degreasing cotton as soft bio-templates. The morphological feature was characterized as hollow microtubules with the range of 50–70 μm in length, 5–6 μm in width, and about 1 μm in thickness. The Cl2 sensing properties were remarkably enhanced in sensitivity and selectivity for In2O3 hollow microtubules. The gas response (Rgas/Rair) of the In2O3 hollow microtubules sensor was 1051 to 10 ppm Cl2 at 200 °C, which was 25 times higher than In2O3 particles. Such outstanding gas sensing performance was ascribed to the hollow morphology, which revealed high specific surface area, abundant oxygen vacancies and low band gap. The gas sensing mechanism was deduced that Cl2 molecules are directly adsorbed on the metal oxide surface and oxygen vacancies.

Determination of Effective Oxygen Adsorption Species for CO Sensing Based on Electric Properties of Indium Oxide

To understand the relationship between adsorbed oxygen on the surface of indium oxide (In2O3) and its CO-sensing property in wet and dry atmospheres, the oxygen adsorption properties and sensor response to CO were investigated. In2O3 particles were prepared by a precipitation method and characterized using X-ray diffraction, scanning electron microscopy, and nitrogen absorption measurements. The O− and O2− adsorption equilibrium constants, K1 and K2, respectively, were calculated from the relationship between the electrical resistance and the oxygen partial pressure (PO2) using a competitive adsorption model. It was found that the values of both K1 and K2 decreased with increasing humidity, indicating a reduction in the amount of oxygen adsorption on the In2O3 surface in a wet atmosphere. The In2O3 particles can detect CO at ppm level in dry and wet atmospheres, although they were greatly reduced in wet atmospheres. Moreover, we found that the sensor response to CO is closely related to the values of K1 and K2.

Microstructure and thermoelectric properties of In2O3/poly(3, 4-ethylenedioxythiophene) composites

Poly(3, 4-ethylenedioxythiophene) (PEDOT) has applications in many areas due to its exciting electrical performance and high stability. Since it has very low thermal conductivity, it is also a good organic thermoelectric material. However, the ZT value of pure PEDOT is rather low, because the electrical properties such as conductivity are still not satisfactory. It is found that the thermoelectric performance can be enhanced by adding inorganic thermoelectric materials into PEDOT to form composites. In this paper, we synthesize a composite of In2O3/PEDOT by chemical oxidation. Microstructure of the composite is studied by X-ray diffraction, infrared spectroscopy, transmission electron microscope, and positron annihilation spectroscopy. The XRD measurements show that the pure PEDOT sample is amorphous, and the crystallinity in composite sample is contributed by In2O3. Besides, the diffraction peaks become sharper with increasing the In2O3 content. Transmission electron microscope measurements confirm that the PEDOT sample is amorphous and the shapes of In2O3 particles are regular. The surfaces of the In2O3 particles are wholly coated with thin layers of PEDOT, and when the In2O3 content is higher than 22 wt%, the In2O3 particles cannot be uniformly dispersed in pure PEDOT layers. The positron annihilation measurements reveal the interface structure in the In2O3/PEDOT composite, which can capture positron and cause the lifetime of positron to increase. The relative quantity of interface increases with In2O3 content increasing. However, when the In2O3 content is more than 22 wt%, the interface structure is destroyed. All the measurements show that when the In2O3 content is lower than 22 wt%, the In2O3 nanoparticles are well dispersed in PEDOT. The electrical conductivity of In2O3/PEDOT composite increases with In2O3 content increasing. At room temperature, the electrical conductivity of PEDOT is 7.5 S/m, while in the In2O3/PEDOT sample with 12.3 wt% In2O3, a maximum electrical conductivity of 25.75 S/m is obtained. When the In2O3 content increases from 0 to 22 wt%, the power factor of the composite increases rapidly from 14.5×10-4 to 68.8×10-4 μW/m·K2. On the contrary, the thermal conductivity shows decrease compared with the thermal conductivity of pure PEDOT. The ZT value of the composite increases from 0.015×10-4 to 0.073×10-4. Our results indicate that the thermoelectric properties of In2O3/PEDOT composite can be effectively improved compared with those of the pure PEDOT

Helical polysilane coating onto hollow spherical indium oxide: Fabrication, characterization and infrared emissivity property study

A new-type of composite combined by helical polysilane (HPS) and hollow spherical indium oxide (In2O3) was designed and fabricated via solution blending. The hollow spheres constructed by In2O3 particles were synthesized via a facile hydrothermal route where it demonstrated larger surface area, enabling the combination of HPS and In2O3 more easily. Meanwhile, the synergetic effect between functional group of HPS and surface hydroxyl of In2O3 improve the reduction of infrared emission. Consequently, the composite shows a superior low infrared emissivity performance at the value of 0.416 (8–14 μm), and the covering of HPS make the composite disperse well in the polar reagent. This work develops a feasible strategy that utilizes metallic oxide to design and synthesize hollow spherical matrix for preparing the low infrared emissivity materials.

Temperature controlled fabrication of chemically synthesized cubic In2O3 crystallites for improved photoelectrochemical water oxidation

The present paper describes the development of indium (III) oxide (In2O3) semiconductor (SC) through chemical bath synthesis using In(NO3)3 as a precursor followed by annealing in air at various high temperatures (600–900 °C). Thin films were prepared over F-doped tin oxide (FTO) coated glass substrate using suspension of the SC powders in ethylene glycol followed by drying at 600 °C. Absorption spectrum measures the direct band gap of In2O3 as 3.60 eV along with an indirect gap of 2.78 eV. Scanning electron microscopy reveals the agglomerated nature of In2O3 particle whereas X-ray diffraction analysis confirms presence of cubic crystallites with preferably (222) orientation. With the gradual rise in annealing temperature (600–900 °C), the size of the crystallites as well as their quality improves, as evident through transmission electron microscopy and PL emission spectra. The In2O3 semiconductor thin films exhibit significant photoelectrochemical activity and long term stability in terms of oxygen evolution reaction from water. The sample annealed at an optimized temperature of 800 °C exhibits the highest photo-current of 1.15 mA cm−2 for H2O → O2 oxidation reaction (in 0.1 M Na2SO4 - pH7, PBS), at 1.51 V vs. RHE (1.23 V vs. NHE) under illumination of 35 mW cm−2. Electrochemical impedance spectra (Mott-Schottky) analysis confirms n-type conductivity for the semiconductors, whereas the action spectra suggest ∼40% incident photon to current conversion efficiency (IPCE) for the optimized materials.

In-MOFs-derived microsphere In2O3 for highly sensitive detecting formaldehyde vapor

Polyhedral, spherical, fragmented In2O3 particles have been prepared via a thermal decomposition by calcining In-MOFs at appropriate temperature and their gas sensing behavior was investigated. The response of the In2O3-500 is 81.5 for 50ppm formaldehyde vapor at 210°C, which exceed the response values of all of the reported In2O3 materials. The In2O3-500 sensor also shown long-term stability (at least 15days), low detection limit of 10ppm and excellent reproducibility. The results indicate that those In2O3 particles have great potential as sensor to detect formaldehyde at low operating temperature.

Preparation of In(OH)3 Nanorods and Nanocubes and the Effect on In2O3 Particle Size in the Microreactor

Indium hydroxide (In(OH)3) nanorods and nanocubes were prepared with a precipitation process using a membrane dispersion micromixer. Indium oxide (In2O3) particles with various sizes were subsequently prepared by calcination of the In(OH)3 particles. A microreactor was used for its improved mixing performance to obtain In(OH)3 particles with a higher degree of crystallinity and In2O3 particles with controllable sizes. The effect of pH, using ammonia as the alkali source, on the In(OH)3 particle shape and In2O3 particle size with the alkali source of ammonia was investigated. In(OH)3 nanorods were synthesized at pH = 9.0, whereas at pH = 7.0, In(OH)3 nanorods and nanocubes were formed. It was observed that, during the calcination process, the In(OH)3 nanorods transformed into In2O3 particles with a size of 20–30 nm, while the In(OH)3 nanocubes transformed into In2O3 particles with a size of 60–70 nm. It was demonstrated through changing the alkali source that the concentrations of NH4+ and NH3 had a great ...

Mesoporous Ag/In2O3 composite derived from indium organic framework as high performance formaldehyde sensor

Mesoporous Ag/In2O3 composite materials with different concentrations of Ag particles have been prepared by the calcination of Ag+-entrapped indium-organic frameworks (InOFs). The structures and components of these MOF-derived Mesoporous Ag/In2O3 composite materials have been characterized thoroughly. Gas sensing measurements indicated that the incorporation of metallic Ag particles into the mesoporous structure significantly improves the gas-sensing properties of In2O3. Specially, the response of 5% Ag-loaded In2O3 sensor to 50ppm formaldehyde is 5 times higher than that of pure In2O3 particles at 210°C, which is among the best formaldehyde sensor materials reported to date. Also, Ag/In2O3 composite sensor exhibit short response time (~22s) and excellent recovery. These results indicated that the InOF-derived mesoporous Ag/In2O3 materials maybe can be used to fabricate high performance formaldehyde sensors in practice.

Effect of Capping Agent on the Morphology, Size and Optical Properties of In2O3 Nanoparticles

The Indium Oxide (In2O3) nanoparticles were synthesized through Acacia gum mediated method with the surfactants CTAB (Cetyl Trimethyl Ammonium Bromide) and SDBS (Sodium Docecyl Benzene Sulfonate). The characterization of the synthesized In2O3 nanoparticles was carried out by XRD, FTIR, RAMAN, TEM, SEM, EDAX, UV-Vis and PL techniques. TG-DTA analysis was performed to know the calcination temperature of In2O3 nanoparticles. XRD analysis confirmed the crystalline nature of the synthesized In2O3 nanoparticles. The morphology and chemical composition were characterized by TEM, SEM and EDAX respectively. It was observed that morphology and size of synthesized nanoparticles measured by TEM and SEM analysis were dependent on the type of capping agent (surfactant) used. Raman and UV-Vis spectral analysis confirmed that the band gap value of CTAB capped In2O3 particles were larger than the SDBS capped In2O3 particles. FTIR analysis indicated that the bands were stretched in In2O3 particles capped by SDBS than by CTAB. From the photoluminescence studies (PL technique), a blue shift in the emission peaks of CTAB and SDBS capped In2O3 particles was observed that indicates larger optical band gap than the bulk.

NOx Sensing Characteristics of Semiconductor Gas Sensors under Controlled Oxygen Activity Conditions Using a Proton-Conducting Electrolyte

The formation of highly oxidative and reductive states within and around WO3 and In2O3 during detection of NOx (NO and NO2) was investigated by attaching the metal oxide electrode to a proton-conducting Sn0.9In0.1P2O7 electrolyte, followed by electrode polarization at 200°C. Proton insertion and release occurred at the WO3 electrode, while metal-ion redox reactions proceeded at the In2O3 electrode. Although the hydrogen tungsten bronze formed under cathodic polarization was insensitive to NO and NO2, the WO3 operating under anodic polarization possessed sensitivity toward NO and NO2. Addition of these gases increased the ohmic, charge-transfer, and gas-diffusion resistances in a similar manner. The In2O3 underwent significant changes in NOx sensing ability upon changes in polarity and magnitude of the applied voltage. In particular, under cathodic polarization, the sensor resistance decreased upon addition of NO and NO2 in the range of –0.5 to –1.5 V, but increased upon addition at –2.0 V, due to reduction of In3+ to lower valence states, which selectively absorbed NO2 beginning at –1.7 V. The WO3 and In2O3 sensing abilities were not significantly affected by interference from O2, H2, CO, or n-C4H10, and the sensors became more sensitive toward NO2 as the WO3 and In2O3 particle size decreased.

Structure and Properties of Dual Oxide Particles Doped Ni-Fe/In2O3-WO3 Functional Nanocomposite Coatings

In the present study two types of oxide ceramic particles In2O3 (2.0 g/L) and WO3 (4.0 g/L) were reinforced into the Ni-Fe alloy matrix by electro-codeposition for the first time. Despite lower concentration in the bath solution, incorporation of In2O3 particles was higher (up to 5.5 wt%) as compared to the WO3 particles (up to ∼3.0 wt%). Coatings obtained under optimum condition show permalloy composition (80 wt% Ni-20 wt% Fe) between the range of current density 3.0–5.0 A dm−2. The coatings were characterized by XRD, FESEM, EDAX, TEM and AFM. The effect of incorporation of these oxide particles and current density on the structure and properties of the nanocomposite coatings was investigated. XRD and TEM studies showed fcc lattice of the matrix with preferred orientation along (111) plane but the relative texture coefficient along (111) plane decreases with increasing current density. Dominance of In2O3 particles on the surface morphology of the coatings was also observed. However, results showed that electrical resistivity, corrosion resistance and microhardness (up to 1025 Hv) of the Ni-Fe/In2O3-WO3 nanocomposite were found between those for the Ni-Fe/In2O3 and Ni-Fe/WO3 nanocomposite coatings. Magnetic studies revealed the soft magnetic nature of the nanocomposite coatings.

Preparation of Uniformly Dispersed ITO Nanoparticles Via Direct Oxidation of in-Sn Alloy in Ionic Liquids

Introduction Transparent and electrically conductive metal oxide nanoparticles (NPs) prepared by solution phase synthetic methods have attracted much attention due to their applicability to wet processing, such as ink-jet printing or spin coating, for fabrication of densely packed particulate films, which can be used to improve the performance of solar cells, transparent electrode, and sensors. Among various kinds of metal oxide particles, indium tin oxide (ITO) NPs are useful nanomaterials because of their high electronic conductivity, chemical stability, or unique optical properties induced by their surface plasmon resonance (LSPR) in the near-infrared region. So far, well-dispersed ITO NPs have been prepared by sol-gel technique or solvothermal method, though these conventional techniques required well-trained skills for obtaining particles with well-controlled size and shape. Recently a facile preparation method of colloidal metal particles in organic solvent has been reported with use of low-melting-point metals such as gallium, indium, and tin,[1] in which molten metals were mechanically dispersed in organic solvent containing surfactant molecules by ultrasonication and/or magnetic stirring, resulting in the formation of metal nanoparticles. On the other hand, room temperature ionic liquids (RTILs) with extremely low vapor pressure and thermal stability have been reported to be a useful medium for the preparation and stabilization of noble metal NPs. For example we have reported that the sputter deposition of noble metals such as Au, Ag, or Pt into RTILs produced corresponding ultrafine metal nanoparticles uniformly dispersed in the solution.[2]RTILs are also expected to act as a good medium not only for the preparation of low-melting-point metal NPs by mechanically dispersing but also for the oxidation of resulting metal particles with heat treatment due to high thermal stability of RTILs. However such attempt has not been carried out. In this study, we report a facile preparation of uniformly dispersed ITO NPs via direct oxidation of In-Sn alloy as a precursor in RTILs. Experimental Indium (0.5 g) was added in RTILs (2.0 cm3) of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF4), 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate (HyEMI-BF4), 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (HyEMI-TFSA), N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)amide (TMPA-TFSA), or 2-hydroxyethyl-N,N,N-trimethylammonium bis(trifluoromethanesulfonyl)amide (Ch-TFSA). The mixture was heated at 523 K for 10 h in air with vigorous stirring. Thus-obtained NPs dispersed in the solution were collected by a centrifugation and re-dispersed in acetonitrile for characterization. ITO NPs with different Sn content were prepared in the same method except for the use of an In-Sn alloy (Sn content; 3, 5, 10, 20, 30 wt%) as a precursor in the Ch-TFSA. Results and discussions The particles prepared by the oxidation of pure In metal as a precursor in RTILs of EMI-BF4, HyEMI-TFSA, TMPA-TFSA and Ch-TFSA, exhibited broad diffraction peaks in XRD pattern assignable to cubic In2O3. In contrast, the XRD pattern of particles prepared in HyEMI-BF4 was assignable to orthorhombic InOF. These results indicated that In metal was oxidized with oxygen molecule dissolved in TFSA-based RTILs to produce In2O3 or reacted with fluoride ion produced by the decomposition of BF4 - anion in HyEMI-BF during heat treatment, resulting in the formation of InOF. TEM observation revealed that uniformly dispersed spherical particles with average diameter of 27 and 39 nm were observed in hydroxyl-functionalized RTILs of HyEMI-TFSA and Ch-TFSA, respectively, while largely aggregated In2O3 particles appeared in EMI-BF4 and TMPA-TFSA. These indicated that hydroxyl group in cationic species of RTILs played an important role in the prevention of In2O3NPs in RTILs. To prepare ITO NPs, we carried out the similar preparation protocol, in which In-Sn alloy containing different Sn content (3-30 wt%) were oxidized in Ch-TFSA with vigorous stirring. Thus-obtained particles exhibited the XRD pattern assignable to ITO crystal structure. Figure 1 shows a TEM image of ITO NPs prepared with alloy containing 30 wt% Sn. Polygonal particles with average diameter ca. 40 nm were observed. With an increase in the Sn content from 3 to 30 wt% in alloy as a precursor, the amount of Sn doping in ITO NPs was enlarged from 0.67 to 10 wt%. ITO NPs exhibited a LSPR peak in the near-IR wavelength region in the extinction spectra, the peak wavelength being blue-shifted from 2860 to 2400 nm with an increase in the amount of Sn doping in NPs from 0.67 to 10 wt%.

Microstructure and gas sensing property of porous spherical In2O3 particles prepared by hydrothermal method

Porous spherical In(OH)3 particles with controllable size were hydrothermally synthesized from aqueous In(NO3)3 solution with the help of urea and citric acid. The average size of the synthesized In(OH)3 particles decreased with the increase of the molar ratio between citric acid and In3+concentration. Cubic In2O3 phase was obtained after a hydrothermal process at 160°C and a calcination process at 600°C, while mixed rhombohedral and cubic In2O3 phases were obtained by annealing the hydrothermally synthesized precursor at 180°C. Morphology, internal structure, particle size distribution and specific surface area of the In2O3 particles were characterized. A possible mechanism was proposed to illustrate the growth of In2O3 particles. The gas sensors which prepared with porous cubic In2O3 materials displayed high sensitivity to formaldehyde.

A simple large-scale synthesis of mesoporous In2O3 for gas sensing applications

In this paper, large-scale mesoporous In2O3 nanostructures were synthesized by a facile Lewis acid catalytic the furfural alcohol resin (FAR) template route for the high-yield. Their morphology and structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal and thermogravimetry analysis (DSC-TG) and the Brunauer-Emmett-Teller (BET) approach. The as-obtained mesoporous In2O3 nanostructures possess excellent mesoporous and network structure, which increases the contact area with the gases, it is conducive for adsorption-desorption of gas on the surface of In2O3. The In2O3 particles and pores were both about 15nm and very uniform. In gas-sensing measurements with target gases, the gas sensor based on mesoporous In2O3 nanostructures showed a good response, short response-recovery time, good selectivity and stability to ethanol. These properties are due to the large specific surface area of mesoporous structure. This synthetic method could use as a new design concept for functional mesoporous nanomaterials and for mass production.

Reverse water gas shift over In2O3–CeO2 catalysts

In2O3 has been predicted as an excellent catalyst for CO2 conversion, for both hydrogenation to methanol at low temperature and reverse water gas shift (RWGS), whereas CeO2 promotes RWGS. In the present work, the promotion effect of CeO2 on RWGS over In2O3 was experimentally investigated. Characterizations show that the surface areas of the In2O3–CeO2 catalysts increase from that of pure In2O3 whereas the size of the In2O3 particles in the In2O3–CeO2 samples decreases as the fraction of CeO2 increases. In addition, the presence of CeO2 helps to create more, and stabilizes, oxygen vacancies, on which the dissociative hydrogen adsorption is enhanced and the amount of bicarbonate species resulting from activated CO2 adsorption is increased. The synergistic effect between In2O3 and CeO2 makes the In2O3–CeO2 catalysts exhibit enhanced activity for RWGS over the pure In2O3.

Preparation and characterization of oil-soluble In2O3 nanoparticles and In2O3-SnO2 nanocomposites and their calcined thin films

Oil-soluble In2O3 nanoparticles and In2O3–SnO2 nanocomposites were prepared in oleylamine via decomposition of metal acetylacetonate precursors. Thin films of In2O3 and In2O3–SnO2 were obtained by spin-coating solutions of the oil-soluble In2O3 nanoparticles and In2O3–SnO2 nanocomposites onto substrates and then calcining them. Transmission electron microspectroscopy, scanning electron microspectroscopy, atomic force microspectroscopy, X-ray diffraction, ultraviolet–visible absorption, and photoluminescence spectroscopy were used to investigate the properties of the nanoparticles and thin films. The In2O3 nanoparticles were cubic-phased spheres with a diameter of ~8 nm; their spectra exhibited a broad emission peak centered at 348 nm. The In2O3–SnO2 nanocomposites were co-particles composed of smaller In2O3 particles and larger SnO2 particles; their spectra exhibited a broad emission peak at 355 nm. After the In2O3–SnO2 nanocomposites were calcined at 400°C, the obtained thin films were highly transparent and conductive, with a thickness of 30–40 nm; the surfaces of the thin films were smooth and crack-free.

Comparative Study on the Pulmonary Toxicity of Indium Hydroxide, Indium-Tin Oxide, and Indium Oxide Following Intratracheal Instillations into the Lungs of Rats

ABSTRACTWe studied the pulmonary toxicity of indium hydroxide (In(OH)3), which is produced during a recycling process of indium-tin oxide (ITO), in comparison with that of ITO or indium oxide (In2O3), two raw materials of flat panel displays. One hundred and forty-four male Wistar rats were intratracheally given equivalent doses of 10 mg/kg indium as In(OH)3, ITO, or In2O3 particles, twice a week, for a total of 5 times for 2 weeks. Control rats were given distilled water as a vehicle. After 3 weeks, these rats were serially euthanized, and toxicological effects were determined. Body weight gain was significantly suppressed in the In(OH)3-treated rats compared to that in the control group, but not in the ITO- or In2O3-treated rats. Relative lung weights in all the indium-treated groups significantly increased compared to those in the control group throughout the observation period. Furthermore, lung weights in the In(OH)3 group were significantly higher than those in either the ITO or In2O3 group. Blood indium levels in the In(OH)3-treated rats were much higher, 70- to 200-fold, than those in the In2O3- or ITO-treated rats at each time point. Although the lung indium content decreased gradually during the observation periods, the content in the In(OH)3 group was significantly higher than that in either the ITO or In2O3 group. A histopathological analysis revealed foci indicating a slight to severe pulmonary inflammatory response, including exudation to alveolar spaces, were present in all the indium-treated groups. Interstitial fibrotic proliferation was seen only in the In(OH)3-treated rats. The severity of these lesions in the In(OH)3-treated rats was greater than that in either the ITO- or In2O3-treated rats.The results of our study clearly demonstrated that In(OH)3 particles caused severe pulmonary toxicity when repeated intratracheal instillations were performed in rats. Furthermore, the toxic potency of In(OH)3 in the lung was much higher than that of ITO and In2O3. Accordingly, the toxicity of In(OH)3 particles should be considered in addition to that of ITO and In2O3 particles when indium exposure occurs.

Studies on Electrodeposition, Microstructure and Physical Properties of Ni-Fe/In2O3 Nanocomposite

In2O3 nanoparticles (<100 nm) up to 5 wt% are incorporated into Ni-Fe alloy matrix by electrodeposition which enhance both corrosion resistance and hardness. Plating parameters like current density, concentration of metal ions and In2O3 particles, agitation and the temperature of the bath were optimized to achieve acceptable quality of the coatings. Effect of current density on the development of Ni-Fe/In2O3 nanocomposites and their physical properties was mainly studied. Coatings thus obtained were characterized by SEM-EDAX, XRD, TEM and AFM and surface morphology, crystal structure, microhardness, corrosion resistance, magnetic behavior and electrical resistivity of the nanocomposites were studied. The incorporation of conducting In2O3 particles in a alloy matrix resulted in a higher electrical conductivity than the matrix. X-ray diffraction results showed that the incorporation of In2O3 particles does not affect the Ni-Fe alloy fcc structure but alters the texture of the deposits favoring (111) crystallographic orientation and is independent of the applied current density for deposition. The crystallite size of the nanocomposites is found in the range of 5–13 nm with almost negligible strain.