Influence Of Ni Content Research Articles

Influence of Ni content on impact-abrasion wear resistance of medium-carbon low alloy cast steel

Medium-carbon low alloy wear-resistant cast steel with different Ni contents (0.08 mass%, 0.77 mass%, 1.74 mass%, 2.43 mass%) were heat treated at 1050 °C, followed by water quenching and tempering at 250 °C. The influence of Ni content on the microstructure, hardness, impact toughness and abrasive resistance of the cast steel were investigated. The results showed that the Ni contents increasing hindered the transformation of martensite phase by reducing martensite transformation start temperature (Ms) and martensite transformation finish temperature (Mf). The fine martensite phase after quenching improved the hardness, impact toughness and wear-resistance of the cast steel. The cast steel with low Ni content (0.08% or 0.77%) consists of lath tempered martensite, while the microstructure turns to mixed lath martensite and lamellar twin martensite with higher Ni content. The cast steel with 1.74% Ni showed a hardness of HRC49.5, an impact absorbing energy with V-notch impact absorbing energy of 16.7 J, and the best wear resistance among the samples.

Hexamethylenetetramine-assisted hydrothermal synthesis of efficient and stable Ni-MoCeZr-MgAl(O) catalysts for dry reforming of CH4: Effect of Ni content

Ni-MoCeZr-MgAl(O) mixed oxide catalysts were successfully prepared from the Ce, Zr and Mo promoted hydrotalcite-like compounds (HTLcs) precursors using the simple and effective hexamethylenetetramine(HMT)-assisted hydrothermal synthesis method by tuning the molar ratio of n(HMT)/n(NO3−). The influence of Ni content (3, 4.8, 6, 9 and 12%) on the catalytic performance of these catalysts in dry reforming of methane (DRM) was focused. Adjusting the content of Ni was able to change the metal dispersion and metal particle size, and small-sized (around 7 nm) and evenly dispersed Ni particles were obtained at Ni content of 6%. The catalyst with 6% Ni loading stood out for the high activity and stability, the CH4 conversion of which fluctuated around 95% continuously for 610 h under GHSV of 60,000 mL·gcat−1·h−1, and it was still above 92.8% throughout the 36-h-duration DRM experiments under GHSV of 80,000 mL·gcat−1·h−1. This research may provide a simple and effective methodology for the synthesis of stable and efficient DRM catalysts.

Effect of Ni Content on Double-Target Co-sputtered CrNiN Coatings

Double-target co-sputtered CrNiN coatings were deposited by DC-pulsed magnetron reactive sputtering. The nickel content increases from 0.7 to 5.0 at.% with the increased Ni target current from 0.10 to 0.40 A. The influence of Ni content on preferred orientation and properties of CrNiN coatings was investigated. The results show that the doped Ni enters CrN to form (Cr,Ni)N solid solution. CrNiN coatings are mainly composed of CrN phase and demonstrate CrN(111) preferred orientation. All the coatings present columnar growth pattern. And the less obvious the preferred orientation, the more intense competitive growth, the less sufficient the columnar growth, the finer the columnar crystal and the denser the microstructure. In spite of the most dense structure with finest grains, the hardness of CrNiN coating containing 0.7 at.% Ni is the lowest. The hardness is affected by multiple effects of preferred orientation, grain size, solid solution strengthening, morphology and stress, especially the intensity degree of preferred orientation.

The Influence of Ni Content on the Corrosion Resistance of Cu-Ni-Sn-C-P Sintered Alloys in Poor Quality Fuel

The copper alloys, which were added Nickel show high corrosion resistance. Therefore, they are generally used in environments of poor quality fuel. However, it is expected that we reduce the amount of Ni in copper alloy, due to increase of Nickel consumption in recent years. We used five different types of sintered material samples that are different in the content of Nickel in the present study, to investigate the influence of Ni content to corrosion resistance quantitatively. These samples were used for the experiment of open circuit potentials, anodic and cathodic polarization curves measurements. To simulate environment in poor quality fuel we employed solution of 0.5 M Na2S + 0.1 M NaOH (pH = 13.05). The experiment of open circuit potentials shows that samples that the content of Nickel is less than 42 mass% were formed passivation film on surface of sample during aeration. The experiment of polarization curves measurements show that the each sample was implied behavior of forming passivation film corresponding to potential-pH diagram of Cu in anodic region basically. In addition, the 36.4 mass% Nickel was remarkably improved corrosion resistance.

Effect of Ni content on the electrical and corrosion properties of CrNiN coating in simulated proton exchange membrane fuel cell

In this paper, CrNiN coatings with various Ni content are deposited on 304ss bipolar plates by closed field unbalanced magnetron sputter ion plating from CrNi alloy targets. Simulative working environment of proton exchange membrane fuel cell (PEMFC) is applied to test the electrical and corrosion properties of uncoated 304ss and CrNiN-coated samples. The influence of Ni content on microstructure, phase structure, contact angle with water and electrochemical performance is investigated. Results show that all the coated samples significantly enhanced the corrosion resistance of the 304ss, and the CrN-coated 304ss sample without Ni has the best corrosion resistance of 153.8 and −141.9 mV in the simulated anodic and cathodic environments, respectively. Electrochemical impedance spectroscopy (EIS) studies reveal that the resistance of CrN coating is higher than that of other coated samples and 304ss in the cathodic environment. Furthermore, Interfacial contact resistance (ICR) studies revealed that CrN coating has a superior ICR of 11 mΩ cm2 at a compaction force of 160 N cm−2. In addition, the contact angle of the CrNiN coatings with water is approximately 114°, which is beneficial for water management in PEMFC. Analysis result indicates that the enhanced performance of the coated 304ss bipolar plates is related to the high film density determined by closed field unbalanced magnetron sputter ion plating, and the synergistic function of the CrNiN layered structure.

Methane dry reforming over hydrotalcite-derived Ni–Mg–Al mixed oxides: the influence of Ni content on catalytic activity, selectivity and stability

Ni-containing hydrotalcite-derived catalysts were prepared using different Ni loadings (from ca. 4 to 60 wt%) at the same MII/MIII ratio equal to 3.

Effect of Ni content on the diffusion-controlled growth of the product phases in the Cu(Ni)–Sn system

A strong influence of Ni content on the diffusion-controlled growth of the (Cu,Ni)3Sn and (Cu,Ni)6Sn5 phases by coupling different Cu(Ni) alloys with Sn in the solid state is reported. The continuous increase in the thickness ratio of (Cu,Ni)6Sn5 to (Cu,Ni)3Sn with the Ni content is explained by combined kinetic and thermodynamic arguments as follows: (i) The integrated interdiffusion coefficient does not change for the (Cu,Ni)3Sn phase up to 2.5 at.% Ni and decreases drastically for 5 at.% Ni. On the other hand, there is a continuous increase in the integrated interdiffusion coefficient for (Cu,Ni)6Sn5 as a function of increasing Ni content. (ii) With the increase in Ni content, driving forces for the diffusion of components increase for both components in both phases but at different rates. However, the magnitude of these changes alone is not large enough to explain the high difference in the observed growth rate of the product phases because of Ni addition. (iv) Kirkendall marker experiments indicate that the Cu6Sn5 phase grows by diffusion of both Cu and Sn in the binary case. However, when Ni is added, the growth is by diffusion of Sn only. (v) Also, the observed grain refinement in the Cu6Sn5 phase with the addition of Ni suggests that the grain boundary diffusion of Sn may have an important role in the observed changes in the growth rate.

Characterization and photodegradation activity of hollow Zn1−x Ni x Fe2O4 sphere

Carbon microspheres with good dispersibility were synthesized by hydrothermal method using glucose as raw material. Taking the as-prepared carbon microsphere as the template, a series of hollow Zn1−x Ni x Fe2O4 spheres (x = 0–1 with interval of 0.2) were prepared by chemical precipitation method. The composition, morphology, electrical and magnetic properties of the hollow Zn1−x Ni x Fe2O4 spheres were characterized. The results of nitrogen adsorption–desorption isotherms indicates that the Zn1−x Ni x Fe2O4 catalyst with different Ni content presents different specific surface area. And the adsorption–photodegradation of samples on rhodamine B and methyl orange solutions were discussed. In addition, the influence of Ni content on material photocatalytic activity has been discussed. These results indicated that the recyclable ZnFe2O4 had a better decontaminating activity than other Zn1−x Ni x Fe2O4 spheres.

MOLD FILLING ABILITY AND HOT CRACKING SUSCEPTIBILITY OF AL-FE-NI ALLOYS FOR HIGH CONDUCTIVITY APPLICATIONS

Newly developed high conductivity Al-Fe-Ni alloys are expected to be used for various electronic and electrical applications instead of conventional low conductivity Al casting alloys. In this research, influence of Ni content on the mold filling ability and hot cracking susceptibility of Al-Fe-Ni alloys was investigated. The cast microstructure of Al-0.5Fe-xNi alloys mainly consists of primary aluminum and 2nd phases, and the kind of the 2nd phases is dependent on the Ni content. As the Ni content was increased, Al3Ni phase became dominant as the 2nd phase. Although the Ni additions reduced the conductivity a little, Al-0.5Fe-xNi alloys with nickel ranging from 0.5 to 2% showed significantly higher electrical conductivity than conventional Al-Si based alloys. The mold filling ability measured by fluidity serpentine test of Al-Fe-Ni alloys decreased significantly when more than 1%Ni was added. The mold filling ability measured by using a pressure die-casting method showed the similar results with respect to the Ni content. Meanwhile, hot cracking susceptibility was increased remarkably when more than 0.5%Ni was added.

Effect of Ni content on CrNiN coatings prepared by RF magnetron sputtering

CrNiN coatings with various Ni content were deposited by RF reactive magnetron sputtering from Cr–Ni alloy targets. The influence of Ni content on phase structure, preferred orientation, microstructure and hardness of the coatings was investigated. The results show that RF sputtered CrNiN coatings are mainly composed of CrN phase, present columnar growth, and have a nearly feature-less surface morphology. The preferred orientation changes from CrN(220) to CrN(111) as Ni content is increased from 2.92 to 8.79 at.%. The doped Ni can favor dense structure and improve coating surface smoothness, but cannot refine grains. The coating hardness is increased by adding 2.92 at.% Ni due to the effect of discontinuous Ni coverage on hindering grain boundary sliding, dense structure and smoother surface. As Ni content is increased to 8.79 at.%, the hardness is then decreased as a result of too much soft metal and larger grain size.

Effect of Ni Alloying on the Corrosion Resistance of 355MPa High Weather-Resistant Steel

Based on the 355MPa high weather-resistant steel, three different kinds of high weather-resistant steels were designed by varying the content of Ni. The the corrosion resistance of the high weather-resistant steel as well as the influence of Ni content on the corrosion resistance were studied in the present investigation. The results of the cycle corrosion tests indicated that with the addition of Ni, the corrosion resistance was improved to some extent. The rust layer of the weathering steel was composed of α-FeOOH and γ-FeOOH at the beginning of corrosion, and the α-FeOOH turned to γ-FeOOH which enhanced the corrosion resistance.

Crystallization of Al-based Amorphous Alloys in Good Conductivity Solution

The corrosion-induced crystallization of Al94–xNixGd6 (x = 6 and 10, in at.%) metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniques. The transmission electronic microscopy (TEM) result reveals that crystalline intermetallics and oxides present on the electrochemically thinned hole edge, and the phase separation occurs in the matrix of the as-spun ribbons with the circumferential speed Rc of 29.3 m/s. In addition, the bending and cracking of the samples occur after corrosion. The influence of Ni content on the phase separation, bending and cracking can be explained by the fact that the percolation of the backbone clusters in the amorphous alloy melts and glasses is enhanced by increasing the composition of Ni.

Highly c-axis oriented ZnO:Ni thin film nanostructure by RF magnetron sputtering: Structural, morphological and magnetic studies

Nickel doped zinc oxide (ZnO:Ni) thin films with different Ni concentrations were deposited on silicon substrates at 400°C by reactive magnetron sputtering using a mixture of Ar and O2 gases. The X-ray diffraction and azimuthal patterns of the ZnO:Ni were carried out, and the quality of the strong preferred orientation of crystalline columns in the direction [001] perpendicular to the substrate surface were analysed. The grain size, distribution, and homogeneity of the thin film surfaces were studied by FE-SEM. The EDX and mapping confirmed that the Ni is incorporated into ZnO uniformly. The microstructure of the textured columns was analysed by TEM and HRTEM analyses. The average thickness and length of the columns were found to be about 50nm and 600nm, respectively. The rise of ferromagnetism by the influence of Ni content was studied by VSM magnetic studies at room temperature.

Influence of Ni Content on Dry Sliding Wear Behavior of Sintered and Carburized Steels

The dry sliding wear behavior of two sintered and carburized steels with different Ni amounts has been investigated. The microstructure of the two steels comprises martensite, bainite, and the Ni-rich austenite. Under the sliding conditions investigated, wear is either oxidative or adhesive. In both cases, the lower amount of the soft Ni-rich austenite results in a better wear resistance. A design procedure for parts subject to dry sliding wear applications is proposed, based on the maximum acceptable wear depth, in order to evaluate the practical significance of the differences between the two materials.

Microstructure and mechanical properties of W–Ni–N coatings prepared by magnetron sputtering

W–Ni–N coatings were fabricated by direct current magnetron sputtering technique. The influence of Ni content on the microstructure, surface morphology and mechanical properties of coatings was investigated by using X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy, nanoindentation and scratch tests. The results showed that the addition of Ni into W–N coatings induced a change of grain morphology from polygon to granular shape leading to the reduction in contact area between the coating and the substrate. The roughness of coatings also decreased upon the addition of Ni. Therefore, the adhesion strength of W–Ni–N decreased from 60 to 38N as Ni content is increased from 0 to 21at.%. In contrast, the hardness increased slightly at first and then decreased with Ni concentrations. The maximum hardness of 38GPa was obtained at 10.2at.% Ni, corresponding to a composite structure consisting of nc-W2N+nc-Ni3N+nc-Ni.

Structural, dielectric and magnetic properties of Ni substituted zinc ferrite

NixZn1−xFe2O4 ferrite has been synthesized by the ceramic method using Ni CO3, ZnO, Fe2O3 precursors. The influence of Ni content on the structural, morphological, electrical and magnetic properties of NixZn1−xFe2O4 ferrites is studied. The X-ray diffraction (XRD) analysis reveals that the samples are polycrystalline with spinel cubic structure. The SEM images of NixZn1−xFe2O4 ferrite show that the grain size decreases with an increase in the Ni content. The tetrahedral and octahedral vibrations in the samples are studied by IR spectra. Frequency dependence of dielectric constant shows dielectric dispersion due to the Maxwell–Wagner type of interfacial polarization. Conduction mechanism due to polarons has been analyzed by measuring the AC conductivity. Impedance spectroscopy is used to study the electrical behavior. Magnetic properties of NixZn1−xFe2O4 are studied by using hysteresis loop measurement. The maximum value of saturation magnetization of 132.8emu/g obtained for the composition, x=0.8, is attributed to magnetic moment of Fe3+ ions.

Influence of Ni content on microstructure of W–Ni alloy produced by selective laser melting

W–Ni alloy parts were produced with selective laser melting (SLM) and the influence of the Ni content on the microstructure evolution and microhardness was investigated methodically. The resultant microstructure of the SLM specimens with a Ni content of 10wt.%, 20wt.% and 40wt.% exhibited bar-shaped structures, dendrites and honeycomb structures respectively. It was found that a higher Ni content decreased the melt viscosity and increased the densities of W–Ni parts. The microhardness decreased on the other hand with increasing Ni content. The microstructure formed in the SLM process was characterized by a mixture of typical liquid phase sintering (LPS) microstructure and W dendritic structure. This revealed that the forming mechanism of the SLM process on W–Ni particles was a combination of LPS and partial melting of W particles. The microstructure showed that SLM process improved the bonding ability of the powder particles and therefore enhancing the mechanical properties.

Hydrogen Oxidation Kinetics and Performance of Ni-LaNbO4 Cermet Anodes for Proton Conducting SOFCs

Ni composite anodes for Ca-doped LaNbO4 (LCNO) based proton conducting solid oxide fuel cells were fabricated as screen-printed Ni-LCNO cermets on a dense self-supported LCNO electrolyte and as a semi-symmetrical cell consisting of a ∼ 15 μm thick LCNO electrolyte deposited on a tape-cast Ni-LCNO anode support. The influence of Ni content and sintering temperature on the polarization resistance of the Ni-LCNO interface was investigated. The interface was characterized by electrochemical impedance spectroscopy, and the effects of temperature, pO2 and pH2O on the area specific resistance (ASR) at open circuit were used to determine the rate limiting steps of the hydrogen kinetics of these anodes. The total electrode response is 1.1 Ωcm2 for 40/60 (vol) Ni/LCNO cermet support, at 800°C in wet H2, and the activation energy ∼ 0.5 eV. Three processes were suggested to contribute to the polarization resistance of Ni-LCNO cermet anodes, the most resistive believed to correspond to a charge transfer process at the interface between hydrogen atoms on or in Ni and protons in the electrolyte.

Influence of Ni on stability of martensitic transformation in Zr50Cu50−xNix

Abstract Influence of Ni content on the stability of martensitic transformation and microstructure evolution was investigated in Zr 50 Cu 50− x Ni x ( x = 0, 5, 10, 15). Microstructural observations revealed that the both B19′ and Cm martensites were present in all the alloys investigated. The thermal behaviors results indicated that the initial M s increased from 433 K to 699 K with an increase of Ni content from 5 to 15 mol.%. For x = 5, the forward and reverse martensitic transformation disappeared after thermal cycling. For x = 10 and 15, both transformation still remained even after 10 cycles. Two-step transformation behaviors were observed on both forward and reverse transformation in x = 15 alloy. Ni addition decreased the transformation hysteresis. Microstructural observations revealed the Ni addition up to 10 mol.% suppressed the decomposition of ZrCu into Zr 2 Cu and τ 5 phases during 10 thermal cycling treatments. These results indicated that the addition of Ni over 10 mol.% stabilized the martensitic transformation during thermal cycling.

The influence of Ni content on the characteristics of C–Ni thin films

C–Ni thin films have been obtained by dual sputtering of graphite and nickel targets. This configuration allows the synthesis of coatings with high carbon content and an accurate control of the composition and degree of dispersion of metallic particles within the coatings. The Ni/(Ni+C) ratio within the films, as determined by XPS (X-ray photoelectron spectroscopy) analysis, varied between 5.8% and 62%. The films were investigated by using Grazing Angle X-ray Diffraction (GXRD), Raman spectroscopy and Scanning Electron Microscopy (SEM).An evolution of the coatings morphology from a poor defined columnar structure to a well defined one with the increasing relative Ni content has been noticed. Depending on the chemical composition of the films, a large distribution of the electrical resistivity values of the films has been observed. The variation of the coating resistivity is related to a change from a structure consisting of metallic particles embedded in an amorphous carbon matrix to a metallic crystalline structure.