Mixture Of NiO Research Articles

Cr2O3–NiO mixed oxides thin films for p-type transparent conductive electrodes

The Cr2O3–NiO mixed oxides’ thin films were formed by means of the layer-by-layer magnetron sputtering deposition of Cr2O3, NiO, and Cr2O3 layers on c-plane sapphire substrates. These thin-film structures, subjected to subsequent annealing, constituted a combination of the monocrystalline (0001) Cr2O3 and nonordered nickel oxide phase, which was a mixture of NiO and Ni2O3. The annealing at 900 and 1000 °С in air facilitated the diffusion of Ni and Cr atoms into the layers. Varying the annealing time allowed us to control the uniformity of the Ni and Cr distribution, the microrelief of the film surface, the transmittance in the visible region, and the sheet resistance of the Cr2O3–NiO thin-film structures. Thus, the films annealed at 900 °C during 30 min were characterized by a uniform distribution, a relatively weakly developed surface, a low sheet resistance, and the highest Haacke's Figure of Merit of 1.49 × 10–9 Ω–1. The formation of mixed Cr2O3–NiO oxides by the proposed approach was found to be an effective way to improve the performances of Cr2O3 based p-type transparent conductive electrodes.

Structural Features Investigation of a Highly Dispersed NiO–SiO<sub>2</sub> Catalyst by X-Ray Analysis of the Atomic Pair Distribution Function

In the present work NiO and NiO–SiO2 were investigated by X-ray diffraction and radial atomic pair distribution methods. By X-ray diffraction method, it was determined that the NiO particle sizes have coherent scattering region of more than 100 nm, while the NiO–SiO2 sample has a particle size of about 2–3 nm. At the same time, full-profile Rietveld simulation does not describe the effects observed on diffraction: the asymmetry of peaks, the appearance of an additional shoulder of peak 111 in the area of small angles, so the radial atomic pair distribution method was used to analyze the structure. During the simulation of the experimental atomic pair distribution curve, 3 different models were used: pure NiO, a mixture of NiO and Ni2SiO4, and a modified NiO model with Si embedded in the lattice. The latter model was created based on the assumption of silicon incorporation into the NiO structure, which can be evidenced by X-ray diffraction data. According to the results of radial atomic pair distribution modeling it is the latter model that gives the best description of the observed effects: significantly increased unit cell parameter, compared to the sample without SiO2 addition, as well as decreased metal cation–oxygen distances in the structure, while cation–cation distances are increased.

Corrosion Properties and Passive Film Interface of Inconel 718 in NaNO3 Solution for Laser-Assisted Electrochemical Machining.

Laser-assisted electrochemical machining (ECM) is an ideal manufacturing method for Inconel 718 (IN718) because of the method's high efficiency and good surface quality, and the basis for and key to laser-assisted ECM is its anodic electrochemical dissolution behavior. In this study, IN718 in a 10 wt % NaNO3 solution was subjected to innovative electrochemical testing and laser-assisted ECM experiments to investigate its corrosion properties and the passive film characteristics formed on its surface. The passivation-related behaviors and structures of the passive film were investigated based on open-circuit potentials, dynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy. It was found that there was obvious active-passive-transpassive transition behavior, and the structure of the passive film in laser-assisted ECM exhibited pores and defects, resulting in weak corrosion resistance, compared with IN718 under ECM without laser irradiation. The chemical composition of the passive film was obtained by X-ray photoelectron spectroscopy. The results showed that the passive film was composed mainly of a mixture of NiO, Ni(OH)2, Cr2O3, CrO3, Fe2O3, α-Fe2O3, α-FeOOH, Nb2O5, NbO, MoO3, MoO2, and TiO2. The passive film formed by laser-assisted ECM was rich in NiO and TiO2 and lacked Cr2O3 and MoO3, which validated its pores and defect structures. A corresponding schematic model was also proposed to characterize the interface structure between the IN718 substrate and the passive film. Laser-assisted ECM tests were performed under different current densities and machining times, and the corrosion morphology of IN718 was identified. Corrosion pits and a loose product layer appeared on the machined surface at low current densities, and the dissolution mechanism was pitting. The quantity and depth of the corrosion pits dispersed on the machined surface clearly decreased as the current density increased. Finally, a quantitative corrosion model was established to characterize the dissolution behavior of IN718 in NaNO3 solution during laser-assisted ECM.

Role of power on physiochemical properties of Mo- and Ni-based nanoparticles manufactured by laser ablation

In this study, the influence of the laser energy on Molybdenum (Mo) and Nickel (Ni) based nanoparticles (NPs) produced by laser ablation is presented. The nanoparticles' physicochemical properties were studied for laser energy values from 70 to 300 mJ for Mo and from 100 to 250 mJ for Ni. X-ray Diffraction, Atomic Force Microscopy, Dynamic Light Scattering, Atomic Absorption, and UV–Vis Spectroscopy allowed for studying the crystalline structure, morphology, composition, and optical properties. Both samples Mo and Ni at low laser energies produce amorphous nanoparticles with sizes of 30 and 15 nm, respectively. When the laser energy increases, the crystalline structure, size, concentration, and optical properties of the molybdenum and nickel nanoparticles change. However, the shape of the nanoparticles (quasi-spherical) is independent of the laser energy. In Mo, NPs showed a monocrystalline MoO3 phase at intermediate laser energy. At high values of laser energy, Mo is the most stable structure. In Ni, NPs showed a polycrystalline NiO phase at medium laser energy. At high values of laser energy, a mixture of NiO and Ni is the most stable structure. The particle size remains constant for intermediate and high laser energy values. The main difference between the hydrodynamic diameter and the particle size was 7 nm. UV–vis spectra of Mo nanoparticles showed the formation of two compounds: (MoO4)2- and H2MoO4. UV–vis spectra of Ni nanoparticles showed that the absorbance decreased continuously above 200 nm, except for the sample prepared at 150 mJ. As the laser energy increases, the concentration of NPs increases in both cases. We concluded that the Ni sample at 150 mJ shows potential stability compared to the others due to the electrical charging of the material during the ablation process. As the most important result found in this research, it can be considered that the laser energy affects the structural, morphological, and compositional properties of Ni and Mo-based nanoparticles. Nevertheless, as expected, the most significant influence was observed in the nanoparticle concentration. The novelty of the work consists of the laser energy on the band gap and, precisely, the results for Ni-based nanoparticles. In this case, it was impossible to measure this parameter for almost all samples, possibly due to the magnetic influences, since the unoccupied d states atoms, such as Ni, are responsible for the ferromagnetism or high paramagnetism of the transition elements. There is a direct connection between the magnetic properties and the electrical conductivity. On the other hand, in the case of Mo-based nanoparticles, the influence of laser energy on the bandgap is almost negligible.

Effect of manganese addition to Ni-Cu oxides on properties and activity in the oxidation of volatile organic compounds

Transition metal oxides are suitable for the total oxidation of harmful volatile organic compounds. The effect of Mn addition to Ni-Cu oxides was investigated to determine the optimum cation composition for achieving high catalytic performance in the total oxidation of ethanol and toluene, which were chosen as model volatile organic compounds. Single component (Ni, Cu, Mn), binary Ni-Cu, and ternary (Ni-Cu-Mn) oxide catalysts with various Ni:Cu and Ni:Cu:Mn molar ratios were prepared by precipitation of aqueous nitrate solutions followed by calcination at 500 °C in air. The catalysts were characterized by AAS, powder XRD, Raman spectroscopy, N2 adsorption, H2-TPR, and XPS spectroscopy. The addition of Mn to Ni-Cu oxides led to the formation of Ni-Cu-Mn mixed oxides with spinel structure and Ni-Mn mixed oxides (Ni6MnO8, NiMnO3). On the other hand, the Ni-Cu catalysts contained a mixture of NiO and CuO. In the H2-TPR experiments, the Ni-Cu-Mn oxides were reduced at lower temperatures compared to the binary Ni-Cu catalysts. The catalytic performance of Ni-Cu-Mn oxide catalysts was higher than that of the Ni-Cu catalysts. As the Mn concentration increased, the concentration of metal-bound oxygen raised, while the concentration of oxygen vacancies slightly decreased. A linear correlation was revealed between the surface concentrations of oxygen vacancies determined by XPS and specific reaction rates in ethanol and toluene oxidation over the Ni-Cu and Ni-Cu-Mn catalysts. For the Ni-Cu-Mn mixed oxides and the mixture of Ni and Cu oxides, a synergistic effect was found in the oxidation of both model compounds.

Performance of fuel reactor in chemical looping combustion system with mixed metal oxides

The Chemical Looping Combustion (CLC) technique shows great potential as an innovative technology to enhance thermal efficiency of system. It has a capability to achieve complete carbon capture (up to 100 %) and prevent the formation of nitrogen oxides (NOx). The current study focuses on the computational analysis of bubble behavior within fuel reactor of CH4-fueled Chemical Looping Combustion (CLC) setup. During numerical examination, a user-defined function (UDF) was utilized to integrate a reaction kinetics into active environment of fuel reactor. In the current research, CuO and NiO are employed as mixed oxygen carrier substances, while CH4 is utilized as fuel within the combustion procedures. The preparation, growing, rising, and bursting of bubbles' hydrodynamics has been observed; additionally, it has been evaluated in addition to examining the solidus-gaseous molar fraction within a fuel reactor. The current simulation opted for a gaseous fuel composed of natural gas (CH4), a hydrocarbon, alongside mixed metal oxides as CuO and NiO in varying ratios. A mixed metal oxide has been chosen in the proportion of CuO as 0.3 and NiO as 0.7, CuO as 0.5 and NiO as 0.5, and CuO as 0.7 and NiO as 0.3 by weightage. The fuel conversion rate has been observed 20 %, 25 %, and 30 % respectively for the different metal oxide mixture proportions. It has been clearly noticed that in the mixture of NiO and CuO; if the CuO amount is more, then the fuel conversion rate is high due to highly reactivity of CuO at high temperatures.

Doping strategies towards acceptor-doped barium zirconate compatible with nickel oxide anode substrate subjected to high temperature co-sintering

Protonic ceramic fuel cells (PCFCs) are attractive next-generation fuel cells working at intermediate temperature (450–700 °C). Currently, the most common method to produce PCFCs is based on co-sintering anode-supported half cells composed of thin BaZr0.8Y0.2O3-δ (BZY20) electrolyte layers and thick NiO anode substrates. However, the BZY20 electrolyte reacts with NiO at the high temperature during co-sintering (1400–1600 °C), leading to significant loss of dopants in the electrolyte and thereby degradation in the conductivity. With the aim to improve the chemical compatibility between the BaZrO3-based electrolyte and NiO, in this work, we annealed the mixture of NiO and BaZrO3 doped with different dopants, and found that good compatibility was obtained between NiO and BaZr0.8Yb0.2O3-δ or BaZr0.8Tm0.2O3-δ at 1500 °C, and NiO and BaZr0.8Yb0.2O3-δ at 1350 °C. Furthermore, BaZr0.8Y0.1Yb0.1O3-δ and BaZr0.8Y0.12Yb0.08O3-δ also showed good chemical compatibility with NiO at 1350 and 1500 °C. Then, the half cells using the BaZrO3 electrolyte doped with Y and Yb were fabricated, and the ionic conductivities of the electrolytes implemented into the co-sintered half cells were measured directly in wet hydrogen. The results revealed that BaZr0.8YxYb0.2-xO3-δ (x = 0.10, 0.12, 0.13) showed higher conductivity than that of BaZr0.8Y0.2O3-δ, and BaZr0.8Y0.1Yb0.1O3-δ exhibited the highest conductivity among the three Y and Yb co-doped samples studied in this work.

Microstructure Analysis, Optical, and Electrical Transport Properties of NiAl2O4/Al2O3 Nanocomposite Powder

The microstructure characterization, optical properties, electrical transport, and dielectric properties of the thermally stable NiAl2O4/Al2O3 nanocomposite powder sample synthesized by the mechanochemical‐assisted solid‐state reaction from the equimolar mixture of NiO and Al2O3 powders are reported. Rietveld refinement, selected‐area electron diffraction pattern, and Fourier‐transform infrared spectrum analyses confirm the formation of a NiAl2O4 spinel phase with a minor Al2O3 phase in the as‐synthesized powder. Transmission electron microscope images reveal the particle size of the powder sample, ≈26 nm. Raman spectrum reveals the presence of NiAl2O4 normal spinel as a major phase in the sample. The temperature and frequency dependence of the dielectric constants of the NiAl2O4/Al2O3 nanocomposite are explained by Koop's phenomenological theory. The electric modulus approach is used to analyze the electrical transport and dielectric relaxation of NiAl2O4/Al2O3 at different temperatures. The electric modulus plot with elevated temperature shows a dielectric loss peak and reflects interesting information on the grains and grain boundaries of the material with varying temperatures.

Preparation of Mg-Mn doped LiNiO2 via direct Indonesian Mixed Hydroxide Precipitate Lithiation

<span lang="EN-US">Using local raw materials affects the development of the Li-ion batteries industry in Indonesia, which is highly important for the sustainability of electric vehicles. Cathode material affects around 40-50% of Li-ion batteries production costs. The utilization of cheap and local nickel sources for nickel rich-cathode material is a promising approach for reducing LIBs cell cost. Mixed Hydroxide Precipitate (MHP) which contain significantly high amount of nickel can serve as the nickel source for LiNiO<sub>2</sub> cathode material This article proposes an effective and economical method to obtain nickel rich cathode material via direct high thermal lithiation of MHP. Non negligible amount of Mn and Mg in MHP can be directly used as a dopant. Based on XRD analysis, a mixture of NiO and LNO phase can be detected. The presence of Mg and Mn impurities is not observable. The SEM images confirms the irregular shape of the as-prepared LNO. The FTIR confirm the absence of residual Li. Based on the findings, a pretreatment technique is required to be explored in the future.</span>

High-Temperature Wear Performance of hBN-Added Ni-W Composites Produced from Combustion-Synthesized Powders

This work reports on the spark plasma sintering (SPS) of self-propagating high-temperature-synthesis (SHS)-derived Ni-W and Ni-W-2wt%hBN (4:1 molar ratio of metals) powders. The synthesis was carried out from a mixture of NiO and WO3 using Mg + C combined reducers through a thermo-kinetic coupling approach. Experiments performed in the thermodynamically optimal area demonstrated the high sensitivity of combustion parameters and product phase composition to the amount of reducers and hBN powder. The powder precursors with and without the addition of hBN were consolidated using SPS at a temperature and pressure of 1300 °C and 50 MPa, respectively, followed by a thorough phase and microstructural characterization of the obtained specimens. SHS-derived powders comprised the nano-sized agglomerates and were characterized by a high sinterability. The specimens of >95% density were subjected to ball-on-plate dry sliding wear tests at a sliding speed of 0.1 ms−1 and a distance of 1000 m utilizing an alumina ball of 10 mm in diameter under a 15 N normal load. The tests were performed at a temperature of 800 °C. A significant improvement in wear behavior was demonstrated for SHS-processed composites in comparison with their counterparts produced via conventional high-energy ball milling technique owing to the phenomena of ‘micro-polishing’, cyclic ‘self-healing’ and fatigue. However, the decisive effect of hBN addition in imparting lubrication during an HT wear test was not confirmed.

Hybrid NiO/Co3O4 Nanoflowers As High-Performance Anode Materials for Lithium-Ion Batteries

The construction of advanced nanostructures as well as the hybridization of different active materials are highly desirable for achieving lithium-ion batteries (LIBs) anode with superior electrochemical performance. Herein, we developed a simple solvothermal method, with a subsequent annealing process for the synthesis of flower-like NiO/Co3O4 with dense pores on the petals and investigated its potential as anodes for LIBs. The as-prepared hybridized NiO/Co3O4 anode material exhibited an impressive capacity (1428.8 mAh g-1 at a current density of 0.1 A g-1 after 100 cycles, and 668.6 mAh g-1 at 1 A g-1 after 600 cycles), which is a significant improvement compared with its corresponding building blocks as well as the physical mixture of NiO and Co3O4. This excellent performance is attributed to the unique flower-like porous architecture and the synergetic effect of two electrochemically cooperative anode materials, simultaneously overcoming the conductivity deficiency and capacity fading due to severe volume expansion during cycling. The material design principle and synthesis approach are expected to be useful for other battery electrodes, as well as in other applications such as catalysis, microwave absorption and gas sensing.

Hybrid NiO/Co3O4 nanoflowers as high-performance anode materials for lithium-ion batteries

The construction of advanced nanostructures as well as the hybridization of different active materials are highly desirable for achieving lithium-ion batteries (LIBs) anode with superior electrochemical performance. Herein, we developed a simple solvothermal method, with a subsequent annealing process for the synthesis of flower-like NiO/Co3O4 with dense pores on the petals and investigated its potential as anodes for LIBs. The as-prepared hybridized NiO/Co3O4 anode material exhibited an impressive capacity (1428.8 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles, and 668.6 mAh g−1 at 1 A g−1 after 600 cycles), which is a significant improvement compared with its corresponding building blocks as well as the physical mixture of NiO and Co3O4. This excellent performance is attributed to the unique flower-like porous architecture and the synergetic effect of two electrochemically cooperative anode materials, simultaneously overcoming the conductivity deficiency and capacity fading due to severe volume expansion during cycling. The material design principle and synthesis approach are expected to be useful for other battery electrodes, as well as in other applications such as catalysis, microwave absorption and gas sensing.

Dry reforming of methane over Ɣ-Al2O3 supported NiCo and NiCoCu nano-catalysts

ABSTRACT In the present study, Ni-Co, Ni-Cu bimetallic nanocatalyst (BMNC), and Ni-Co-Cu trimetallic nanocatalyst (TMNC) were synthesized on the base using the thermogravimetric method. The thermogravimetric method is a pyrometallurgical route (TGPR). These nanocatalysts were produced from the reduction reaction of binary and ternary mixture of NiO, Co3O4, and CuO metal oxide nanoparticles (NPs), along with a base with methane gas. The reduction reaction was carried out at 830°C with 23vol.% of methane as a reducing agent under atmospheric pressure. The properties of BMNC and TMNC were analysed by XRD, FESEM, TPO, and BET and then their the nanocatalysts’ performance was evaluated with dry reforming of methane (DRM). The XRD results indicated that in the production of NPs-C, the utilised metal oxides were converted into metal NPs, which created bi- and tri-metallic bonding with the base. BET analysis demonstrated that the surface area and pores volume of the TMNC reduced as the primary CuO particles entered the pores, due to the smaller average size of these particles in comparison to nickel and cobalt oxide NPs. In addition, the catalytic results revealed that BMNC has the highest catalytic performance compared to TMNC, due to the absence of CuO and the appropriate synergistic effect of nickel-cobalt in the DRM. The TPO analysis confirmed the decrease in the amount of carbon sediment in the TMNC, resulted from the presence of Cu.

Enhanced selectivity of syngas in partial oxidation of methane: A new route for promising Ni‐alumina catalysts derived from Ni/ γ‐AlOOH with modified Ni dispersion

Partial oxidation of methane was studied over new Ni nanocatalysts prepared from Ni-impregnated γ-AlOOH, which were compared with their counterparts derived from impregnated γ-Al2O3 and α-Al2O3. The prepared catalysts were characterized by powder X-ray diffraction (XRD), N2-sorption, H2-temperatue programmed reduction, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, CO2- and NH3-temperature-programmed desorption, Raman spectroscopy, CO chemisorption, and diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO. Employing γ-AlOOH as the support precursor resulted in significantly improved textural properties and catalytic activity. The structure of the support precursor and its surface properties showed a strong influence on the type of Ni active species and their interactions with the support. γ-AlOOH-derived catalysts showed NiO as the dominant Ni species when calcined at 500°C to 650°C, while NiAl2O4 became the sole phase at higher temperatures. On the other hand, mixtures of NiO and NiAl2O4 formed over γ-Al2O3, calcined before impregnation, regardless of the precalcination temperature. All γ-AlOOH-derived catalysts showed higher specific surface areas compared to their counterparts derived from impregnated γ-Al2O3. Upon calcination at moderate temperatures, γ-AlOOH-derived catalysts also showed modified textural and morphological properties of the Ni active particles, including higher Ni dispersion, larger metal surface area, and smaller Ni crystallites. The support precursor and the pretreatment conditions showed a strong influence on the catalytic performance, which was referred to their significant effect on the type of the Ni species and interactions with the support. All catalysts showed higher catalytic activity than the α-Al2O3-derived catalyst, with CH4 conversion between 86% and 88.5% at 700°C. While γ-AlOOH- and γ-Al2O3-derived catalysts calcined at 650°C showed a stable CH4 conversion around 88%, and higher syngas selectivity than the other catalysts, Ni/γ-AlOOH-650 showed the highest selectivity to syngas, with a H2/CO ratio very close to 2.0. The improved Ni dispersion and the enhanced syngas selectivity obtained in the preset work demonstrate that using γ-AlOOH as a support precursor holds a great promise for the development of a new route for more efficient Ni catalysts compared with the widely studied γ-Al2O3 and α-Al2O3 support precursors.

Pseudocapacitance of chemically stable MnO2-NiO mixture layer on highly conductive Sb doped SnO2 nanowire arrays

We report the electrochemical properties of MnO2–NiO mixture layer that is coated on highly conductive SnO2 nanowires. In this study, the effect of the nanowire conductivity and coating composition on the pseudocapacitic performance was systematically examined. To control the electric conductivity of the nanowire, Sb was doped into SnO2 during vapor–liquid-solid (VLS) process. Subsequently, pure or NiO added MnO2 layer was electrochemically deposited on SnO2 nanowire arrays. Structural studies show that the electrodeposition layer uniformly and conformally covered the nanowires. Low concentration Sb doping (up to 5 at%) increases the electric conductivity of the nanowires which work as an electron transport layer of the pseudocapacitor. Electrochemical studies indicate that the addition of NiO to MnO2 promotes a charging/discharging process through Faraday reaction by changing the oxidation mechanism of MnO2. These results guide a design of the metal oxide mixture for the pseudocapacitor application.

XPS spectral analysis for a multiple oxide comprising NiO, TiO2, and NiTiO3

XPS spectra collected from a mixture of NiO, TiO2, and NiTiO3 cannot be analyzed using a standard curve-fitting method; thus, principal component analysis (PCA) was conducted to accurately determine the ratio of various oxides in the mixture. Model samples comprising NiO, TiO2, and NiTiO3 exhibited a complex-shaped Ni 2p spectrum with a satellite peak, from which the atomic ratio of NiO and NiTiO3 could be accurately quantified using the PCA. In contrast, the Ti 2p spectrum exhibited a symmetric shape despite comprising both NiTiO3 and TiO2 states; thus, the PCA results predicted the ratio inaccurately. However, the PCA results showed linear correlation with the theoretical values over an entire range. Thus, accurate ratios were obtained using a calibration curve. The PCA procedure for multiple oxides was applied to angle-resolved XPS spectra for thermally oxidized nickel titanium alloy. The results revealed the in-depth distribution of NiO, TiO2, and NiTiO3 on the surface of the alloy.

Microstructural characterization of NiAl–Al2O3 composite materials obtained by in situ aluminothermic reduction of NiO for potential coating applications

Aluminothermic reactions between Al microparticles and preoxidized Ni particles were carried out to fabricate mixed compounds of NixAly containing in situ generated Al2O3. The mixed composites were obtained by applying a thermal treatment to either a mixture of NiO and Al powders or to a stacking of powders. The effects of the particle size, thickness of oxide, heating ramp and temperature on the microstructure of the NiAl–Al2O3 coating are discussed. The results indicate that Ni3Al forms first during the synthesis, followed by NiAl and Al3Ni2 while Al3Ni forms on cooling. Moreover, the alumina was observed to form a continuous network surrounding NixAly intermetallic compounds. It derives that these composites have a potential to form self-healing coatings.

A high-resolution characterization of the initiation of stress corrosion crack in Alloy 690 in simulated pressurized water reactor primary water

Stress corrosion crack initiation of alloy 690 in simulated pressurized water reactor primary water was studied through high-resolution characterization of grain boundaries at different stages of the initiation process. It was found that a compact layer of Cr2O3 initially forms over a migrated grain boundary, driven by the diffusion of Cr. After the surface Cr2O3 is breached by straining, oxygen diffusion results in formation of a mixture of NiO and Cr2O3 along the grain boundary. The crack nucleates along either the previous grain boundary or the heavily oxidized migration zone when the boundary strength falls below the local stress.

Using rare earth oxychlorides as precursors to prepare rare earth alloys through solid cathode electrolysis in molten CaCl2

Rare earth oxychlorides were investigated for the first time as precursors to prepare rare earth alloys through solid cathode electrolysis in molten CaCl2, and to demonstrate this approach the electrochemical reduction of a LaOCl and NiO mixture to LaNi5 was performed. It was found that LaOCl is a good solid precursor of La because it neither absorbs water from the air nor reacts with the molten electrolyte. The electrode process consists of two simple and rapid steps: the reduction of NiO to Ni, followed by the reduction of LaOCl on the formed Ni, generating LaNi5. Moreover, as most of the rare earth elements have similar physicochemical properties and their oxychlorides are easily available, our findings may promise a general route for the preparation of rare earth alloys.

Novel Method for NTC Thermistor Production by Aerosol Co-Deposition and Combined Sintering.

A novel three-stage process to produce NTCR sensors is presented. In this process, an uncalcined powder mixture of NiO and Mn2O3 was deposited onto an alumina substrate via aerosol co-deposition (AcD). Then, an electrode structure was screen-printed onto the surface and the composite film was sintered in a multifunctional temperature treatment. Thereby, the sintering of the electrode, the formation of the NiMn2O4 spinel and the removal of film strains took place simultaneously. This enabled a significant reduction in energy demand and workload. The manufactured sensors, both as first prototypes, as well as miniaturized chip components, were characterized by a single-phase cubic NiMn2O4 spinel structure, mechanical stability and electrical properties that were similar to those of classical NiMn2O4 bulk ceramics or tempered aerosol deposited (AD) NiMn2O4 films. Particularly noteworthy was the high reproducibility and low variation of the NTCR parameters, such as the specific resistivity at 25 °C ρ25, the electrical resistance at 25 °C R25 and the thermistor constant B. The NTCR parameters were as aging-stable as for NiMn2O4 bulk ceramics or tempered NiMn2O4 AD-films and could even be further improved by thermal post-treatment.