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Showing papers on "Mixed oxide published in 1993"


Journal ArticleDOI
TL;DR: In this paper, an XPS and XAES (X-ray exited Auger electron spectroscopy) investigation was carried out to elucidate the structure of TiO 2 -SiO 2 mixed oxide systems in the broad range of the component concentrations.
Abstract: An XPS and XAES (X-ray exited Auger electron spectroscopy) investigation was carried out to elucidate the structure of TiO 2 -SiO 2 mixed oxide systems in the broad range of the component concentrations (3 wt % ≤TiO 2 ≥97 wt %). It is found that a homogeneous TiO 2 -SiO 2 solid solution exists at low TiO 2 concentrations (TiO 2 ≤10 wt %). At least two phases (silica-rich content and titania-rich content) coexist in the intermediate TiO 2 concentration range. At low SiO 2 concentrations (TiO 2 ≥85%), silicon forms titanium silicate coating TiO 2 particles

198 citations


Journal ArticleDOI
TL;DR: In this paper, the synthesis of transparent colloidal solutions of extremely small zinc oxide, titanium dioxide, hematite, and titanium/iron mixed oxide particles (2 nm < d 20 nm) in water, ethanol, and 2propanol is described.
Abstract: This paper gives an overview of the author's activities in the research of extremely small metal oxide particles in recent years. In particular, the synthesis of transparent colloidal solutions of extremely small zinc oxide, titanium dioxide, hematite, and titanium/iron mixed oxide particles (2 nm < d 20 nm) in water, ethanol, and 2-propanol is described. Quantum (Q)-size effects are observed during particle growth and at me final stages of synthesis. A simple molecular orbital (MO) picture is presented for the qualitative interpretation of these effects, while quantitative calculations have been carried out using a quantum mechanical model developed by Brus. The photophysical properties of the particles have also been investigated extensively. Fluorescence spectra of the ZnO sols suggest that adsorbed electron relays are necessary to shuttle electrons from the conduction band to lower-lying traps. Excess negative charge on the particles, resulting from either deprotonated surface hydroxyl groups or from photogenerated or externally injected charge carriers, causes a blue-shift in the electronic absorption spectrum, which is explained by electrostatic and MO models. The zero point of charge (pHzpc) of the aqueous colloidal suspensions has been determined by several independent methods. While zinc oxide, titanium dioxide, and titanium/iron mixed oxide particles exhibit considerable photocatalytic activity (as illustrated for the reduction of molecular oxygen and the oxidation of various halogenated carboxyl acids), hematite particles are only found to oxidize S(IV) under bandgap illumination to a reasonable extent (ϕ < 0.3). A mechanism involving surface-bound molecules and free radical intermediates is presented to explain these differences in reactivity.

171 citations


Journal ArticleDOI
TL;DR: In this article, the electrochemical properties of three intermetallic phases (Al 2 Cu, β-Al 3 Ta and Al 3 Zr) were compared to high purity Al in inert buffer solutions and dilute halide solutions.

132 citations


Journal ArticleDOI
TL;DR: In this article, the effect of temperature, loading, Cu/Cr ratio, particle size and the pretreatment in reducing or oxidizing environment on the activity and selectivity of the CO oxidation and the NO reduction with CO, both individually and simultaneously, were considered.

70 citations



Journal ArticleDOI
TL;DR: In this article, supercritical fluid extraction was used to make aerogels of TiO 2, ZrO 2 and two mixed oxides, having surface areas from two to five times greater than their conventionally prepared equivalents.
Abstract: Supercritical fluid (SFC) extraction was used to make aerogels of TiO 2 , ZrO 2 and two TiO 2 /ZrO 2 mixed oxides, having surface areas from two to five times greater than their conventionally prepared equivalents; additionally the mixed oxides have higher surface acidities than the two single component oxides Heat treatments, either during catalyst preparation or reactor testing, always resulted in small to significant decreases in surface areas in the aerogel-containing samples These samples were used as supports for Mo-Ni catalysts for the hydroprocessing of gas oil in a pilot-plant scale reactor The high ZrO 2 containing materials were found to be unstable under reaction conditions and were nearly inactive; in contrast, the high TiO 2 containing catalysts, while somewhat unstable, are more active on a surface area basis than Al 2 O 3 or conventional TiO 2 equivalent supported Mo-Ni catalysts This improvement is attributed to properties inherent in the SCF prepared supports; these results also indicate that support acidity contributes to hydrotreating activity

48 citations


Journal ArticleDOI
TL;DR: In this paper, the photocatalytic properties of MoO[sub 3]/TiO [sub 2] mixed oxide powders were evaluated by the degradation of 1,4-dichlorobenzene (DCB).

44 citations


Patent
03 Jun 1993
TL;DR: A silicon-aluminium mixed oxide produced by flame hydrolysis and having a composition of from 1 to 99.999 wt.% Al2O3, the remainder being SiO2 is described in this article.
Abstract: A silicon-aluminium mixed oxide produced by flame hydrolysis and having a composition of from 1 to 99.999 wt.% Al2O3, the remainder being SiO2. The mixed oxide exhibits an amorphous structure in the X-ray diffraction pattern and consists of intergrown primary particles. In these primary particles crystallites are present; these crystallites having sizes of between one and 200 nanometres and the specific surface area of the powder being between 5 and 300 m2/g. The silicon-aluminium mixed oxide is produced by a process wherein silicon halide and aluminium halide are vaporised in a particular ratio to one another, and are homogeneously mixed with air, oxygen and hydrogen in a mixing unit by means of a carrier gas. This mixture undergoes combustion in a burner of known construction and, after the separation of the solids from the vapour phase, any traces of halide possibly adhering to the product are separated off in a further processing step by means of moist air at elevated temperature.

44 citations


Journal ArticleDOI
TL;DR: In this paper, the direct decomposition of nitrogen monoxide (NO) to N2 and O2 was carried out over valency-controlled La2−xA′xCu1−yB′yO4 mixed oxide catalysts with a K2NiF4-type structure.
Abstract: The direct decomposition of nitrogen monoxide (NO) to N2 and O2 was carried out over valency-controlled La2−xA′xCu1−yB′yO4 (A′ = Sr, Ba, Ca, Ce; B′ = Zr, Al) mixed oxide catalysts with a K2NiF4-type structure. The catalysts were characterized by XRD, XPS, redox titration, and oxygen TPD. It was confirmed by XPS that the surface and bulk compositions generally agreed and by redox titration that the average oxidation number (AON) of copper varied widely from 1.60 to 2.30. XPS showed that the valency of surface copper agreed with AON for AON ≤ 2, while it was in the Cu2+ state for AON > 2.0. The amounts of oxygen desorbed in TPD and the oxygen nonstoichiometry of La2−xSrxCuO4 increased with x in parallel. The catalytic activity for NO decomposition showed a maximum at x = 0.4—0.5, and a good correlation was found between the catalytic activity and AON for all of the catalysts tested. The decomposition of dinitrogen oxide (N2O) was also carried out for La2−xSrxCuO4 for a comparison. Based on the much slower r...

37 citations


Journal ArticleDOI
TL;DR: In this paper, the dependence of the catalytic activity upon the preparation methods has been studied and a new oxalic precursor is compared to those precipitated from an ammonia solution and is particularly studied because it leads to more selective phase β stabilized at room temperature.

36 citations


Journal ArticleDOI
TL;DR: In this article, a coprecipitation-calcination procedure was used to obtain mixed oxides of the general formula Fe2-xCrxO3 with increasing Cr content.
Abstract: Mixed oxides of the general formula Fe2–xCrxO3 have been prepared by a coprecipitation–calcination procedure. The precursors contain a crystalline goethite-like phase and an amorphous trihydroxide phase if Cr is present. Calcnnation for 5 h at 673 K resulted in crystalline powders whose surface areas decrease from 102 to near 20 m2 g–1 with increasing Cr content. IR spectra suggest that the structure of these materials consists of a superstructure of the corundum-type lattice of haematite. In parallel with the decrease of surface area, the smallest slit-shaped pores arising from goethite-to-haematite topotactic decomposition progressively disappear. Cr is observed to form chromate species, some of which are exposed on the surface of the calcined materials. These species are thought to have a role in the catalytic combustion activity of these materials. The optical behaviour of the powders in the IR, visible and UV regions is discussed.

Patent
Thierry Chopin1, Olivier Touret1
15 Dec 1993
TL;DR: In this article, the authors proposed new compositions based on a mixed cerium and zirconium oxide (solid solutions) having very high specific surfaces, that is to say at least greater than 80 m/g and preferably of at least 100 m /g or even 150m /g.
Abstract: The invention relates to new compositions based on a mixed cerium and zirconium oxide (solid solutions) having very high specific surfaces, that is to say at least greater than 80 m /g and preferably of at least 100 m /g or even 150m /g, the said surfaces moreover being thermally stable. The amounts of zirconium in solid solution in the cerium oxide can be very large, for example between 1 and 60 atom %. They are obtained according to a process consisting in heating an aqueous mixture containing, in the required stoichiometric proportions, a soluble cerium compound, such as ceric nitrate, and a soluble zirconium compound, such as zirconyl nitrate, in recovering, especially by filtration, the reaction product thus formed and then finally, optionally, in calcining this product. The compositions according to the invention can be used as catalysts and/or catalyst supports (substrates), in particular in the field of automobile afterburning.

Journal ArticleDOI
TL;DR: In this article, the particle formation processes were investigated as a function of VOCl3 concentration by laser light-scattering and by collecting particles directly onto transmission electron microscopy grids.
Abstract: V2O5–TiO2 and V2O5–Al2O3 mixed oxide powders were synthesized in a hydrogen-oxygen flame using VOCl3, TiCl4, and Al(CH3)3 as precursors. The particle formation processes were investigated as a function of VOCl3 concentration by laser light-scattering and by collecting particles directly onto transmission electron microscopy grids. In the V2O5–TiO2 system, the oxides condense as an intimate mixture at all three VOCl3 concentrations. Spherical particles, 40 to 70 nm in diameter, are obtained. In the V2O5–Al2O3 system, chain-like particles composed of an intimate mixture of V2O5 and Al2O3 form at the lowest VOCl3 concentration. At high VOCl3 concentrations, the chain-like particles have a core-mantle structure (a core mainly of Al2O3 and a mantle mainly of V2O5). The crystalline form and the surface area of these mixed oxides were determined by x-ray diffractometry, FT-IR spectroscopy, and BET analysis by nitrogen desorption. These measurements indicate that amorphous vanadium oxide forms at low VOCl3 concentrations, and V2O5 is obtained at the higher VOCl3 concentrations. The structure of the amorphous vanadium oxide matches that published for vanadium oxide “supported” catalysts.

Journal ArticleDOI
TL;DR: In this article, the formation reactions of IrO2/TiO2 mixed oxide films supported on titanium metal plate were followed by thermoanalytical (simultaneous TGA, DTG, DTA) and combined TGA-MS techniques.
Abstract: The formation reactions of IrO2/TiO2 mixed oxide films supported on titanium metal plate were followed by thermoanalytical (simultaneous TGA, DTG, DTA) and combined thermoanalyticalmass spectrometric (TGA-MS) techniques. The electrochemical characterization of the fired coatings was made by cyclic voltammetry. The thermal decomposition of the titanium precursor salt, titanium diisopropoxide bis-2,4-pentanedionate, shows a major change in the presence of hydrated iridium (iii) chloride. Due to the catalytic effect of the added noble metal, an almost complete conversion of the organic components of the precursor mixture to CO2 and H2O is observed in the combustion stage. Chlorine, from thermal decomposition of the iridium salt, is produced in a separate stage at higher temperatures, indicating that a sequence of steps occurs prior to the oxide formation. For iridium chloride alone a complexation between the metal ion and the solvent (isopropanol) is observed, leading eventually to H2O and CO2 production (combustion step) between 300 and 500° C. The cyclic voltammetry results indicate that the features of the precursor reaction affect the charge storage capacity of the oxide films.

Journal ArticleDOI
TL;DR: In this paper, the reduction and sulfidation of Fe 2O_3 and FeAl 2O-3 sorbents were investigated by thermogravimetric analysis (TGA), and the results showed that mixed iron-aluminum oxides were reduced more slowly than pure iron oxide.
Abstract: The reduction and sulfidation of Fe_2O_3 and Fe_2O_3-Al_2O_3 sorbents were investigated by thermogravimetric analysis (TGA). Mixed iron-aluminum oxides were reduced more slowly and by a more complex mechanism than pure iron oxide. Several phases that were responsible for this difference were identified by temperature-programmed reduction (TPR), X-ray diffraction (XRD), BET surface area (BET), and scanning electron microscopy (SEM). Sulfidation of reduced sorbents in the TGA at 600 "C produced two crystalline phases: high-temperature, hexagonal pyrrhotite (Fe_(1-x)S), and unreacted FeAl_2O_4. The reaction of the pure and mixed oxide with a mixture of H_2S-H_2-H_2O-N_2 was studied in a tubular microreactor to evaluate the performance of these materials as high-temperature H2S sorbents. At 650 °C the mixed oxide yielded considerably lower prebreakthrough outlet H_2S levels than the pure iron oxide. Regeneration in pure SO_2 and SO_2-air mixtures of sulfided samples resulted in complete conversion of iron sulfide to iron oxide and quantitative recovery of elemental sulfur.

Journal ArticleDOI
TL;DR: In this article, mixed metal oxides were examined as potential catalysts for the dehydrogenation reaction of ethylbenzene, and the surface area, pore volume and pore size distribution of these catalysts were measured.
Abstract: The mixed metal oxides TiO2-Fe2O3 and ZrO2-Fe2O3 were examined as potential catalysts for the dehydrogenation reaction of ethylbenzene. The acidic and basic properties and surface area, pore volume and pore size distribution of these catalysts were measured. The catalytic activities can be correlated very well with the surface area and the acidity and basicity of ZrO2-Fe2O3 catalysts. However, for TiO2-Fe2O3 catalysts, the surface area, the amount of acidic and basic sites and TiFe2O5 crystallinity are all important factors affecting the catalytic activities for ethylbenzene dehydrogenation. A synergistic effect was found for the TiO2-Fe2O3 and ZrO2-Fe2O3 catalyst system and also for the TiO2-Fe2O3-ZrO2 system, i.e. the activities of these catalysts can be ranked in the following order: TiO2-Fe2O3-ZrO2>TiO2-Fe2O3 >ZrO2>Fe2O3>TiO2. Meanwhile, all of these catalysts showed higher activities than the conventional potassium-promoted iron catalysts.

Journal ArticleDOI
TL;DR: In particular, the mixed oxide CuO-SrTiO3 was shown to be more sensitive to CO2 than the mixed-oxide CuO/Sr TiO3.
Abstract: The capacitances of CuO mixed with BaSnO3, CaTiO3, and ZnO are dependent on the CO2 concentration, similarly to that of CuO—BaTiO3. In particular, the mixed oxide CuO—SrTiO3 is more sensitive to CO2 than CuO—BaTiO3, and the mixed-oxide capacitor CuO—BaSnO3 is promising for sensing CO2 over a wide range of concentrations. Moreover, addition of Ag to CuO—BaTiO3 mixed oxide is effective for enhancing the sensitivity to CO2. The sensitivity (CCO2/Cair) to 2% CO2 of Ag-added CuO—BaTiO3, which has been calcined at 700 °C followed by operation for 60 h, is as high as 70.

Journal ArticleDOI
TL;DR: In this article, a one-step synthesis of isobutyraldehyde from methanol and ethanol over mixed oxide (TiO2-Al2O3, TiO2 -SiO2, SiO 2 -ZrO2 and ZrO 2 ) supported vanadium oxide catalysts was investigated at atmospheric pressure and 350 °C.
Abstract: A one step synthesis of isobutyraldehyde from methanol and ethanol over mixed oxide (TiO2-Al2O3, TiO2-SiO2, TiO2-ZrO2 and TiO2-SiO2-ZrO2) supported vanadium oxide catalysts was investigated at atmospheric pressure and 350 °C. The V2O5/TiO2-SiO2 catalyst showed a better performance in terms of total conversion and product selectivity than the other catalyst systems.

Journal ArticleDOI
TL;DR: In this paper, a series of Ni/WO3-Al2O3 catalysts have been prepared by systematically varying the weight loading of WO3 and the pH during adsorption/impregnation.
Abstract: A series of Ni/WO3–Al2O3 catalysts have been prepared by systematically varying the weight loading of WO3–Al2O3 and the pH during adsorption/impregnation. The catalysts developed an increased interaction between the impregnated nickel and the supported metal oxide; the charge on the mixed oxide resulted in the impregnated nickel cation to be preferentially adsorbed onto tungsten sites of the composite supports. The amount of nickel associated with tungsten oxide was found to be a function of both the tungsten oxide weight loading and the impregnation pH. An increase in the negative charge due to hydrolysis of the tungsten oxide phase in the aqueous impregnant is proposed to result in a tungsten oxide associated nickel that is twice as large for the catalysts prepared at pH 6 than that at pH 4. The Ni/support interaction formed during adsorption/impregnation and drying were studied by temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO). The tungsten oxide and associated nickel were found to form a nickel tungstate compound which reacted with H2 at ca. 1050 K but could be regenerated by TPO. An Ni/Al2O4 type surface compound was also formed that was reduced at ca. 1150 K.

Patent
06 Oct 1993
TL;DR: Titanium dioxide mixed oxide is prepared by flame hydrolysis having a surface area of from 10 to 150 m /g and containing from 1 to 20% by weight of aluminium oxide or from 1.5 to 15% of silicon dioxide as discussed by the authors.
Abstract: Titanium dioxide mixed oxide prepared by flame hydrolysis having a BET surface area of from 10 to 150 m /g and containing from 1 to 20% by weight of aluminium oxide or from 1 to 20% by weight of silicon dioxide. It is prepared by vaporising aluminium chloride or silicon tetrachloride, transferring this together with an inert gas into the mixing chamber of a burner, mixing with hydrogen, air and gaseous titanium tetrachloride, burning the 4-component mixture in a reaction chamber and separating the titanium dioxide mixed oxide from the gaseous reaction products.

Patent
10 Mar 1993
TL;DR: In this paper, an alkylation catalyst to form adducts or alkylates of a C 3 -C 9 olefin with a C 4 to C 9 isoparaffin comprising a sulfated mixed oxide of titanium and nickel was presented.
Abstract: Disclosed is an alkylation catalyst to form adducts or alkylates of a C 3 -C 9 olefin with a C 4 to C 9 isoparaffin comprising a sulfated mixed oxide of titanium and nickel, wherein the percent by weight of titanium is at least 80%; of nickel is in the range 1-4%; and of sulfur in the range 1-10%. Also disclosed are the appropriate ratios of olefin to isoparaffin and the use of adamantane to increase yields.

Journal ArticleDOI
TL;DR: In this paper, a study of the oxidations of o-xylene, n-butane and benzene on V-P, V-Mo and V-Ti mixed oxides, the commercial catalysts for the synthesis of anhydrides, was carried out.
Abstract: Vanadium is a key element in the formulation of catalysts for the production of anhydrides by selective vapor oxidation with molecular oxygen. A study of the oxidations ofo-xylene,n-butane and benzene on V-P, V-Mo and V-Ti mixed oxides, the commercial catalysts for the synthesis of anhydrides, was carried out. The oxidation ofo-xylene on the three catalysts was the most facile reaction leading to high yields in phthalic anhydride; on the contrary in the oxidation ofn-butane only V-P mixed oxide was active and selective. V-P mixed oxide is active and selective in the oxidation of all the feedstocks and can be identified as the most polyfunctional catalyst. V-Mo is active and selective in botho-xylene and benzene oxidation and V-Ti only ino-xylene oxidation. Moreover the lesser selectivity in phthalic anhydride observed with V-P and V-Mo mixed oxides has been attributed to parallel oxidation reactions to the formation of phthalic anhydride, evidenced by a higher amount of phthalide.

Journal ArticleDOI
TL;DR: In this paper, a novel method for the synthesis of pillared smectites by refluxing a mixture of bentonite and nano hydroxy aluminium oxide sol in aqueous medium is reported.

Journal ArticleDOI
TL;DR: In this paper, the initial sticking coefficient on the non-segregated surface of an Al-6.5at%Li alloy was found to be 0.048 and the reaction of this surface with oxygen leads to oxide formation at exposures < 10 L by a two-step process: oxygen atoms react first with the lithium atoms located at the surface for exposures of 0.5 L and then also react with the aluminum atoms at higher exposures.

Journal ArticleDOI
TL;DR: The properties of PbSc0.5Ta 0.5O3-(x) PbZrO3 ceramics (0.075
Abstract: The properties of (1-x) PbSc0.5Ta0.5O3-(x) PbZrO3 ceramics (0.075

Journal ArticleDOI
TL;DR: In this paper, the synthesis of mixed oxide powders by a copreciprtation route, using a mixture of (MH4)HCO3 (NH4) 2CO3, trieihylamine and formaline, in the presence of a soluble polymer such as polyvinyl alcohol (PVA), was described.
Abstract: This paper describes the synthesis of mixed oxide powders by a new, versatile copreciprtation route, using a mixture of (MH4)HCO3 (NH4) 2CO3, trieihylamine and formaline, in the presence of a soluble polymer such as polyvinyl alcohol (PVA). Each of the precipitating mixtures is chemically equivalent to one mole of triethylammonium carbonate. The composition of the mixed oxide system prepared is: MN2O4 (spinels; where M = Ni(ll). Cu(ll), Zn(ll), Co(ll) N = Felll), Cr(lll)) and RBa2Cu3Ox, (ceramic superconductors; where R = rare-earths). X-ray diflractometry (XRD), energy dispersive X-ray spectroscopy (EDXS) and scanning electron microscopy (SEM) observations are used for the characterization of the final products. The novelty of this route is its simplicity, cost effectiveness and the ability to produce fine, homogeneous, electronic grade materials.

Journal ArticleDOI
TL;DR: The addition of F− to Ba-Ti mixed oxide catalysts significantly improves the catalytic performances for the oxidative coupling of methane (MOC), which can achieve high C2 yields at wide feed composition range and high GHSV.
Abstract: The addition of F− to Ba-Ti mixed oxide catalysts significantly improves the catalytic performances for the oxidative coupling of methane (MOC), which can achieve high C2 yields at wide feed composition range and high GHSV. The effect is particularly marked for the BaF2− TiO2 catalysts containing more than 50 mol% BaF2. The C2 yield of 17% and the C2 selectivity of > 60% were achieved over these catalysts at 700 ° C. After being on stream for 31 h, the ≥ 50 mol% BaF2-TiO2 catalysts showed only a 1–1.5% decrease in the C2 yields. Results obtained by XRD show that various Ba-Ti oxyfluoride phases were formed due to the substitution of F− to O2−.

Journal ArticleDOI
TL;DR: In this article, the authors discuss the effect of different types of noise on the quality of the air quality of outdoor air quality and show that the effect can be worse than that of indoor air pollution.
Abstract: Al, Zr, Si, Ti, Zn, Mgから構成される種々の二元金属複合酸化物を触媒とし, 酸素過剰雰囲気下でのプロパンによるNOの選択還元反応を検討した。単独酸化物の中では, アルミナが最も高い活性を示したが, これに他の金属を複合させた複合酸化物の活性はアルミナよりも低かった。これに対して, 酸化亜鉛-シリカ, チタニア-シリカ複合酸化物は, これらを構成している元素の単独酸化物よりも高い活性を示した。元素構成比率の影響やアンモニアTPDスペクトル測定の結果から, 複合化による表面積の増加およびこれに伴う酸量の増加が活性向上の原因として考えられた。さらに, 吸収ピリジンの赤外吸収スペクトルによる酸化亜鉛-シリカ複合酸化物系の酸性質の検討結果から, ルイス酸点あるいはこれに関係するサイトが活性点になっている可能性が示唆された。

Patent
15 Sep 1993
TL;DR: In this paper, a process for producing an electrically conductive mixed oxide comprises sintering a power mixture comprising from 30 to 98% by weight of titanium oxide, in terms of the amount of titanium based on the total amount of all the metallic elements.
Abstract: A process for producing an electrically conductive mixed oxide comprises sintering a power mixture comprising from 30 to 98% by weight of titanium oxide, in terms of the amount of titanium based on the total amount of all the metallic elements, from 1 to 10% by weight of at least one of titanium metal and titanium hydride, in terms of the amount of titanium based on the total amount of all the metallic elements, and from 1 to 60% by weight of at least one of tantalum oxide and niobium oxide, in terms of the amount of tantalum, niobium, or tantalum and niobium based on the total amount of all of the metallic elements. The process provides a sintered solid comprising titanium, at least one of tantalum and niobium, and a stoichiometrically deficient amount of oxygen. The content of titanium in the sintered solid is from 40 to 99% by weight and the content of tantalum, niobium, or tantalum and niobium in the sintered solid is from 1 to 60% by weight, respectively, based on the total amount of all of the metallic elements in the mixed oxide.

Journal ArticleDOI
TL;DR: Different methods for the formation of NdCrO3 and NdFeO3, having the perovskite-like structure, were studied including the ceramic method, simultaneous precipitation of hydroxides and simultaneous crystallization from aqueous solutions of nitrates.