Vacuum Annealing Temperature Research Articles

Development and investigation of a porous metal-ceramic substrate for solid oxide fuel cells

The process of creating a porous metal-ceramic material based on Ni-Al alloy and gadolinium-doped cerium oxide (CGO) using the thermal explosion method has been investigated. This study aims to analyze the effect of CGO on the thermal explosion parameters and the architecture of the resulting Ni-Al-CGO materials. In this regard, the influence of adding CGO powder to the Ni-Al system on the synthesis process and structure formation during controlled heat loss thermal explosion has been studied. Dependencies of temperature and time characteristics of the thermal explosion on initial parameters have been measured. It has been demonstrated that the concentration of CGO in the initial mixture and heat dissipation from the sample significantly affect the rate of the exothermic reaction. The phase composition of the obtained porous materials, depending on the CGO content and the temperature of subsequent vacuum annealing, was analyzed using X-ray diffraction. The chemical composition and microstructure of the synthesis products were examined through electron microscopy and energy-dispersive X-ray spectroscopy. The possibility of forming metal-ceramic composites with a porosity of 60–65 % for use as supporting substrates for solid oxide fuel cells with a NiO/CGO anode has been shown. An anodic layer of NiO/CGO was applied to a metal-ceramic base of the composition (Ni+25 %Al)+5 %CGO using screen printing, which was then annealed in an air atmosphere at 1300 °C and reduced at 900 °C in a hydrogen atmosphere. The dilatometric method determined that adding 40 wt.% Cr to a mixture of Ni-Al powders reduces the average coefficient of thermal expansion of the new material.

Thermal stability and oxidation resistance of Ti0.22Al0.74Si0.04N coating synthesized by chemical vapor deposition

Addition of Si is known as an effective way to improve the thermal stability and oxidation resistance of TiAlN coatings. In this study, we focused on the thermal stability and oxidation resistance of a Ti0.22Al0.74Si0.04N coating which was deposited on cemented carbide substrate by low pressure chemical vapor deposition (LPCVD). According to X-ray diffraction (XRD), the phase composition of the as-deposited coating is composed of face-centered cubic (fcc-) TiN and wurtzite (w-) AlN. As the vacuum annealing temperature rises from 700 to 800 °C, the hardness increases and subsequently decreases as temperature further rises from 800 to 1100 °C, then remains basically unchanged above 1000 °C. At 900 °C and above, Co diffusion from the substrate into the coating is observed, which affects the mechanical properties of the coating. A maximum hardness of 35.6 ± 3.3 GPa is obtained after annealing in vacuum at 800 °C for 1 h. The results of transmission electron microscopy (TEM) indicate that the coating exhibits a structure similar to that of the deposited state after vacuum annealing at 1200 °C, consisting of nanocrystalline (Ti,Al)N embedded in amorphous SiNx. For the oxidation test, each sample was annealed in air with steps of 50 °C for 1 h within the range of 700–1000 °C. XRD and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the oxide layer is composed of rutile (r-) TiO2, amorphous SiO2 and a dominant amount of amorphous Al2O3 phase forms in the coating after annealing at 950 °C for 1 h. The coating exhibits excellent oxidation resistance with an oxide thickness of only 469 nm after annealing in air at 1000 °C for 1 h.

Influence of vacuum annealing on the structure and phase composition of rapidly solidified hydrogenated orthorhombic titanium alloy

Rapidly solidified alloy based on the orthorhombic Ti2AlNb intermetallic compound is studied in this work as an excellent material for hydrogen absorption and synthesis of powder by hydrogenation-dehydrogenation method. Vacuum annealing and dehydrogenation are indispensable for the formation of the final microstructure and phase composition of the powder. We investigated the influence of vacuum annealing on the structure and phase composition of an alloy based on the Ti2AlNb phase which was obtained by rapid solidification of the melt and then hydrogenated up to 0.2 and 0.65 wt% of hydrogen. The hydrogenated alloy was compared to the non-hydrogenated one subjected to the same vacuum treatment. Vacuum dehydrogenation allows retaining the initial fine-grained structure of the alloy with the β-grain size of less than 25 μm. Also, it leads to a partial decomposition of the metastable β-phase and precipitation of acicular particles of the orthorhombic phase inside the grains and equiaxed particles along the grain boundaries. The morphology of the orthorhombic phase particles changes insignificantly with an increase in the vacuum annealing temperature, while the concentration of the introduced hydrogen and the dehydrogenation temperature have a great influence on their volume fraction.

Effect of CrMoN addition on the thermal stability and cyclic impact resistance of TiVN coatings

By adding V atoms to TiN, the tribological and mechanical properties of TiVN coatings are improved. Multilayered coatings, rather than monolayered ones, may further enhance the mechanical properties and thermal stabilities of TiVN. Therefore, an approach was employed in this study to synthesize gradient-and-multilayered CrMoN/TiVN coatings through vacuum arc ion plating. During the impact fatigue test that utilized a cyclic loading device, the correlation between cyclic impact resistance and coating structures of the deposited coatings were evaluated. Vacuum annealing and high temperature oxidation at temperatures exceeding 600 °C were used to assess the thermal stability of the coatings. Although the as-deposited TiVN coating achieved the highest hardness of 30.2 ± 2.5 GPa, the CrMoN/TiVN multilayer coating only experienced a slight decrease to 29.1 ± 2.2 GPa, which exceeded the solid solution quaternary CrMoTiVN mixture rule prediction. When compared to the high-hardness monolayered TiVN and the low-hardness CrMoN, the CrMoN/TiVN multilayer coatings demonstrated the best resistance to cyclic impact. The TiVN coating displayed the worst oxidation resistance, as shown by the emergence of elongated vanadium-rich Ti-V oxide slats on the surface after oxidation. The CrMoN coating exhibited higher oxidation resistance than TiVN, and small granular chromium oxides formed on the surface beyond 700 °C. The addition of CrMoN to TiVN to form CrMoN/TiVN resulted in improved oxidation resistance by inhibiting the oxidation of TiVN. A different oxidation behavior was found for the CrMoN/TiVN coatings. The design of gradient-and-multilayered CrMoN/TiVN coatings is proven to be advantageous for applications that aim to enhance the thermal stability and cyclic impact resistance of mechanical tools.

Fe ion valence states and oxygen vacancies in the La0.5Sr0.5FeO3-γ ferrite under vacuum annealing

The changes in the substituted La0.5Sr0.5FeO3−γ orthoferrite under vacuum annealing in the temperature range of 200–650 °C have been studied by X-ray diffraction analysis, as well as Mössbauer and Raman spectroscopy. Annealing of the as–prepared ferrite with the rhombohedral structure (R3‾c) resulted in its transition to the cubic one (Pm3‾m) at 650 °C. In the as–prepared ferrite being paramagnetic at room temperature, Fe ions were detected in an averaged–valence state between Fe3+ and Fe4+, which was not revealed with a decrease in the temperature down to 85 K. Gradual oxygen loss and an increase in the number of oxygen vacancies took place with an increase in the vacuum annealing temperature. Only Fe3+ ions were present in the ferrite at a vacuum annealing temperature above 500 °C. Several Zeeman sextets in the Mössbauer spectra associated with Fe3+ ions were resulted from the presence of oxygen vacancies and Fe4+ ions in the local environment of Fe3+ ions. The variations in the ratio of the valence states of Fe ions obtained from Mössbauer data depending on a vacuum annealing temperature allowed determining the content of oxygen in all the investigated samples. The contribution of Fe3+ ions that did not have Fe4+ ions and oxygen vacancies in their local environment was shown to increase with a vacuum annealing temperature from 12% (for the as–prepared sample) to 60% (for the sample annealed at 650 °C). On a whole, the process taking place under vacuum annealing can be characterized as a variation of the local environment of Fe3+ ions towards a decrease in its distortion. It was found that the width of the peaks of the Raman spectra decreased and their amplitude increased with an increase in the vacuum annealing temperature, which also demonstrated the improvement of the structural perfection of the samples.

The Interrelation between Iron Valence and Oxygen Vacancies in Substituted Orthoferrite La0.67Sr0.33FeO3– during Heat Treatment

In this paper, we studied substituted lanthanum orthoferrite La0.67Sr0.33FeO3– γ by Mössbauer spectroscopy using X-ray diffraction data. A series of vacuum annealings was performed in the temperature range of tann = 200–650°C, after which no significant changes in the structure of the samples were detected. The Mössbauer measurements at room temperature show that the Fe ions are in an average valence statebetween Fe3+ and Fe4+. Upon vacuum annealing, as the temperature tann increased, the average hyperfine magnetic field on the 57Fe nuclei and the isomer shift of the spectrum increased, which is associated with an increase in the number of vacancies and, accordingly, a decrease in the amount of Fe4+. Mössbauer measure-ments at 85 K showed that the average valence state of iron does not manifest itself. The hyperfine parameters of the low-temperature Mössbauer subspectra obtained from the model interpretation indicate that one of them belongs to Fe4+ ions, and the rest belong to Fe3+. The presence in the spectra of several sextets related to Fe3+ ions is due to the appearance of oxygen vacancies (breaking of the Fe3+–O2––Fe exchange bond) and Fe4+ ions (weakening of the Fe3+–O2––Fe exchange bond) in the nearest ionic neighborhood of Fe atoms. Both factors cause a decrease in the hyperfine magnetic field and a change in the isomer shift of the spectrum. As a result of model interpretation of the Mössbauer spectra, the numbers of oxygen vacancies and Fe4+ ions per formula unit depending on vacuum annealing temperature tann were determined for all samples. It wasshown that at tann above 450°C, the process of oxygen leaving the lattice ends and only Fe3+ ions are detected.

Низкотемпературные мёссбауэровские исследования замещенного феррита стронция La-=SUB=-0.67-=/SUB=-Sr-=SUB=-0.33-=/SUB=-FeO-=SUB=-3-γ-=/SUB=-

The valence states of Fe atoms and the formation of oxygen vacancies in substituted La0.67Sr0.33FeO3−γ orthoferrite have been studied in detail by low-temperature Mössbauer spectroscopy under oxygen removal. It has been shown that the averaged valence state of Fe atoms is not revealed with a decreasing measurement temperature. This makes it possible to reveal Fe4+ ions. The Analysis of the obtained data allows us to conclude that the presence of several Zeeman sextets associated with Fe3+ ions is related to the appearance of oxygen vacancies and Fe4+ ions in the nearest ionic surrounding of Fe ions. Using the Mössbauer data, the number of oxygen vacancies and oxygen ions has been determined for all the studied samples depending on the vacuum annealing temperature.

Low-temperature Mossbauer studies of substituted La-=SUB=-0.67-=/SUB=-Sr-=SUB=-0.33-=/SUB=-FeO-=SUB=-3-γ-=/SUB=- lanthanum ferrite

The valence states of Fe atoms and the formation of oxygen vacancies in substituted La0.67Sr0.33FeO3-γ orthoferrite have been studied in detail by low-temperature Mossbauer spectroscopy under oxygen removal. It has been shown that the averaged valence state of Fe atoms is not revealed with a decreasing measurement temperature. This makes it possible to reveal Fe4+ ions. The Analysis of the obtained data allows us to conclude that the presence of several Zeeman sextets associated with Fe3+ ions is related to the appearance of oxygen vacancies and Fe4+ ions in the nearest ionic surrounding of Fe ions. Using the Mossbauer data, the number of oxygen vacancies and oxygen ions has been determined for all the studied samples depending on the vacuum annealing temperature. Keywords: perovskites, substituted lanthanum ferrites, X-ray diffraction analysis, Mossbauer spectroscopy, Fe valence states, oxygen vacancies.

Effects of Solvent Treatment on the Formation of Oxygen Vacancy in TiO2 via Vacuum Annealing

In this work, vacuum annealing of hydrothermally prepared titanium dioxide (TiO2) washed with water (W-TiO2) or ethanol (E-TiO2) at different temperatures was performed. Total organic carbon and Fourier transform infrared characterizations confirm the adsorption of washing solvents by TiO2. As the vacuum annealing temperature increases, W-TiO2 appears as white powders, whereas E-TiO2 shows a gradually deepening color with certain absorption of visible light due to the pyrolysis of ethanol. Electron paramagnetic resonance analyses demonstrate that the crystallization of W-TiO2 creates oxygen vacancy (Vo), and the pyrolysis of ethanol favors its formation in E-TiO2. Diffuse reflectance spectra and photocatalytic performances of all TiO2 photocatalysts suggest that Vo is not responsible for visible light absorption. Our work proves that the formation of Vo in TiO2 via vacuum annealing is influenced by the solvent treatment and gives new insights into the origin of Vo as well as its role.

Evolution of coating layers during high-temperature annealing and their effects on magnetic behavior of Fe(Si) soft magnetic composites

Low-loss Fe(Si) soft magnetic composites (SMCs) with atomic-layer-deposition coated layer were successfully prepared in this work. The continuous, compact and uniform Al2O3 layer is found to form tight bonding with the powder base. Evolution of the coating layers has been investigated under different annealing temperatures and closely linked to the magnetic performance of the composites. Results indicate that 1100 °C was the optimal annealing temperature, at which the Fe(Si) SMCs showed lowest core loss of 1237 mW/cm3 and the highest permeability of 99.7 simultaneously (100 mT/100 kHz). Integrity of the coating layer ensures the maximum grain growth and stress removal of powder particles at the highest possible temperature, so as to reduce the hysteresis loss. Formation of high resistivity oxides and silicates (Al2O3, Fe2SiO4 and 3Al2O3·SiO2) after annealing result in a low inter-particle eddy current loss. Besides, high temperature vacuum annealing is helpful to eliminate impurity atoms and decrease the anomalous eddy current loss. The improvement in effective permeability caused by high-temperature annealing is mainly attributed to the relaxation of residual stresses and the reduction of defects. While excessive temperature leads to the decomposition and destruction of the insulation layer, resulting in a significant increase in hysteresis loss, inter-particle and anomalous eddy current loss.

Characterization and photoelectrochemical evaluation of BiVO4 films developed by thermal oxidation of metallic Bi films electrodeposited

This paper reports the synthesis, characterization, and photoelectrochemical evaluation of BiVO4 thin films. Bi thin films were obtained by electrodeposition and then thermally oxidized. Before thermal oxidation, the vacuum annealing temperature of the metallic Bi films significantly changed the final properties. Increasing the annealing temperature of the samples reduced their thickness and increased compaction and the growth in grain size. At the same time, this increase reduced the energy band gap, improved the electrical properties, including the charge carrier absorption and transport, and broadened the Urbach energy. The best performance was obtained with a film vacuum annealed at 10 mTorr and 200 °C, while the thin film annealed at 250 °C showed a deterioration of the material. The energy band gap ranged from 2.44 to 2.53 eV, while the calculated carrier density ranged from 6.24 × 1017 to 3.70 × 1018 cm−3. Based on Mott-Schottky plots, these materials exhibited Vfb of 0.441–0.611 V vs. NHE, making them suitable for photoanodes in solar water splitting and promising routes for hydrogen production.

P‐1.12: Vacuum Annealing Treatment on High‐Performance AlZnO Thin Film Transistors

We explore the effects of vacuum annealing temperature (100, 200, and 300 °C) on device performance of AlZnO thin film transistors (AZO TFTs). The AZO TFTs show excellent electrical properties at annealing temperature of 100 °C, including a saturation mobility of 12.2 cm2V−1s−1, a sub-threshold swing of 186 mV/decade, and an on/off ratio state current ratio over 108. Our findings promote practical application of the AZO TFTs to advanced displays.

Optical characterization of Sb2S3 vacuum annealed films by UV–VIS–NIR spectroscopy and spectroscopic ellipsometry: Determining the refractive index and the optical constants

Using UV–VIS–NIR spectroscopy and spectroscopic ellipsometry (SE) techniques, we studied the optical characteristics of Sb2S3 thin films produced by a one-step thermal evaporation process and annealed for 2 h at various temperatures under vacuum atmosphere. The X-ray diffraction study shows that a structural transition from amorphous to polycrystalline nature occurred at vacuum annealing temperature of 200 °C. According to UV–VIS–NIR spectroscopic measurements, the Sb2S3 films showed a high absorption coefficient in the visible region (α > 104 cm−1) and a direct band gap energy that decreases from 2.00 eV to 1.63 eV as the annealing temperatures increase. Furthermore, we calculate the optical constants of the elaborated Sb2S3 films, such as refractive index n and extinction coefficient k, by fitting the ellipsometric measurements of the pseudo-refractive index < n > and the pseudo-extinction coefficient < k > . It was observed that the obtained values for n at 800 nm are 2.7, 2.9, 3.5, and 4.0 for as-deposited and annealed films, respectively, at 150, 200, and 250 °C. The dielectric properties were also determined using the Wemple DiDomenico (WDD) and Spitzer-Fan models.

RETRACTED: Zhu et al. The Effect of Vacuum Annealing Temperature on the Properties of AlCrTiSiN Coating Prepared by Arc Ion Plating. Coatings 2022, 12, 316

The author and journal retract the article (The Effect of Vacuum Annealing Temperature on the Properties of AlCrTiSiN Coating Prepared by Arc Ion Plating) [...]

Tuning intrinsic defects in ZnO films by controlling the vacuum annealing temperature: an experimental and theoretical approach

The control of native defects in the ZnO material is strongly important for a wide range of technological applications. In this paper, native defects are tuned via the post-thermal treatment of ZnO films in a high vacuum atmosphere. The microstructure of the as-grown ZnO film shows columnar growth and strongly polar-oriented grains along the c-plane (002). Also, the obtained results indicate that the as-grown film contains a high amount of intrinsic defects and strong lattice distortions. After the thermal annealing, the ZnO films display significant structural changes, which are reflected in their electrical, vibrational, and optical properties. Our findings suggest that these changes were attributed to the selective cleanup effect of the native defects and the partial deoxidation process mainly on the exposed particle surface (at high temperatures) tuned up by the thermal annealing temperature. According to DFT calculations, oxygen vacancies (V O ) show lower energy, followed by zinc vacancies (V Zn ) and oxygen interstitials (O i ) indicating that V O defect is the most stable in ZnO. That sequence of stability could suggest the sequence of the annihilation of those defects, which is in line with our experimental findings and also in agreement with literature results.

RETRACTED: The Effect of Vacuum Annealing Temperature on the Properties of AlCrTiSiN Coating Prepared by Arc Ion Plating

In order to further improve the mechanical and tribological properties of AlCrTiSiN coating, annealing treatment was carried out in this work. X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation, scratch tester, friction, and a wear tester were used to characterize and explore the effects of annealing temperature on the coating composition, phase component, surface and cross-sectional morphology, and mechanical properties as well as the friction and wear performance of the AlCrTiSiN coatings. The results indicated that after the vacuum annealing the content of amorphous phase decreased and the average size of nanocrystals increased in varying degrees. With the increase in annealing temperature the coating surface became smoother and the cross-section morphology changed little. The coating hardness first increased and then decreased. The adhesion between the coating and substrate decreased after annealing, but the wear resistance was improved. When the annealing temperature was 800 °C, the mechanical properties and wear resistance of the resulting coating were the best. In this case, the coating hardness was 27 GPa, the critical load was 61 N, the friction coefficient was 0.66, and the wear rate was 1.97 × 10−3 μm3/N·μm−1.

Periodic nano ripple fabricated on diamond and its structure damage repair

Surface nanocrystallization and adjusting chemical compositions are anticipated to be effective strategies for exploring potential applications of diamond in physics, chemistry and biology. In this paper, the morphology evolution of a polycrystalline chemical vapor deposition diamond (PCD) under Ar+ ion beam bombardment was studied. Nano ripple was formed on the substrate. The characteristic sizes, including amplitude (A) and wavelength (W), of ripples could be adjusted by changing ion energy. Meanwhile, chemical compositions of the diamond surface after the bombardment were investigated by Raman spectrum and XPS. Amounts of lattice damage or defects appeared on the surface region of PCD due to a conversion of sp3 C to sp2 C during the ion bombardment. Moreover, high temperature annealing in vacuum was adopted to remove the damage layer. It was proved to be an effective means to restore diamond structure here and the ripple pattern could be still preserved after the thermal treatment. In addition, the variations of the sheet resistance of the PCD, which significantly increases as the increasing annealing time, offer a direct evidence to reveal the extent of restoration of diamond structure.

Unprecedented solar water splitting of dendritic nanostructured Bi2O3 films by combined oxygen vacancy formation and Na2MoO4 doping

We demonstrate the synergetic effect of Na2MoO4-doping and vacuum-annealing on dendritic nanostructured bismuth oxide (Bi2O3) thin films prepared by electrodeposition for visible-light-assisted photoelectrochemical (PEC) water oxidation. After evaluating various extents of Na2MoO4-doping as well as vacuum-annealing temperatures, it was evidenced that both Na2MoO4-doping and vacuum-annealing significantly improved the efficiency and PEC water oxidation performance. Compared to the undoped Bi2O3 photoanode, the optimized Na2MoO4-doped Bi2O3, after vacuum-annealing, resulted in more than 25-fold enhancement in the photoanodic current density to 1.06 mA/cm2 at 1.23 VRHE under AM1.5 G illumination. The PEC enhancement is credited mainly to the increased PEC surface active sites in the Na2MoO4-doped vacuum annealed sample. Confirmed by combined XPS and Mott-Schottky (M − S) analysis, vacuum annealing resulted in surface oxygen vacancies that can contribute to the photocatalytic activity. Besides, Na2MoO4-doping resulted in reduced dimensions of the dendritic structure, revealed by FE-SEM and XRD measurements, resulting in larger surface area and, therefore, larger surface/electrolyte contact. This dual strategy (metal doping + vacuum annealing) can be generalized to assemble photoanodes of other materials used for the production of solar fuels. Our results make a valuable step towards efficient Bi2O3/BiVO4 pn heterojunctions.

Effect of annealing on the microstructure and mechanical properties of Ti0.17Al0.83N coating prepared by low pressure chemical vapor deposition

The face-centered-cubic (fcc) Ti 0.17 Al 0.83 N coating was deposited on cemented carbide insert by low pressure chemical vapor deposition (LPCVD) method. The effects of annealing temperature and atmosphere on the surface and fracture morphology, phase structure, residual stress, and hardness of the Ti 0.17 Al 0.83 N coating were studied. TEM analysis indicated that the as-deposited Ti 0.17 Al 0.83 N coating was self-organized with a periodically alternating Al-rich (9 nm) and Ti-rich (2 nm) nanolamellae. The width of the Al-rich (12 nm) and Ti-rich (3 nm) nanolamellae was increased after annealing in vacuum at 900 °C for 1 h. With the rise of vacuum annealing temperature from 700 to 1200°C, the coating hardness was increased and then decreased while the compressive residual stress was increasing continuously. A maximum hardness of 46.5 GPa was obtained after annealing in vacuum at 900 °C for 1 h. The coating grains cracked with the compressive residual stress of −1.55 GPa after annealing in vacuum at 1100 °C for 1 h. The surface morphology of the coating was basically unchanged after annealing in air at 900 °C for 1 h, while it was completely oxidized with the formation of Al 2 O 3 on the surface after annealing at 1000 °C. • Residual stress of CVD Ti 0.17 Al 0.83 N coating after vacuum annealing was analyzed. • The fraction of Al in Al- and Ti-rich nanolamellae layers are ~0.9 and ~0.6, respectively. • Coating structure before and after vacuum annealing was investigated by TEM analysis. • CVD Ti 0.17 Al 0.83 N hardness reached 46.5 GPa after vacuum annealing at 900 °C for 1 h.

Structural, optical and magnetic properties of vacuum annealed Fe, Mn doped NiO nanoparticles

Iron (Fe) substituted nickel oxide (Ni1−xFexO) and manganese (Mn) substituted (Ni1−xMnxO) nanoparticles at x = 0.05 were prepared using solid-state reaction. The synthesized Ni1−xFexO and Ni1−xMnxO nanoparticles were annealed in vacuum at a pressure of 1 × 0–3 mbar at two different temperatures of 473 K and 673 K for 1 h. The influence of vacuum annealing on the physical properties of Ni1−xFexO and Ni1−xMnxO nanoparticles were studied. The vacuum annealed nanoparticles were characterized by XRD, SEM, EDS, UV–Vis-NIR and VSM instruments to study their structural, surface, chemical, optical and magnetic properties, respectively. From the XRD results it was found that Ni1−xFexO nanoparticles were in cubic structure with Fe impurity phases whereas the Ni1−xMnxO nanoparticles exhibited cubic structure without any impurity phases. The crystallite sizes of the nanoparticles were in the range of 25–30 nm. From the EDS spectra, it was found that the elements such as Fe, Ni, Mn and O were in almost stoichiometric ratio. An increase in optical band gap for Ni1−xFexO and Ni1−xMnxO nanoparticles were observed with an increase of annealing temperature. The pure NiO and doped NiO nanoparticles exhibited ferromagnetism at room temperature. The strength of magnetization decreased in NiO with a rise in annealing temperature. The Ni1−xFexO and Ni1−xMnxO nanoparticles were ferromagnetic at room temperature and the magnetization increased with increase in vacuum annealing temperature. The highest magnetization of 1.4 emu/g, 0.85 emu/g and 0.76 emu/g were observed for NiO, Ni1−xFexO and Ni1−xMnxO nanoparticles, respectively at 673 K. The nanoparticles will be suitable for storage device applications.