Nickel Aluminum Research Articles

Microstructural transformation and corrosion–cavitation behavior of ultrasonic nanocrystal surface modified nickel aluminum bronze (NAB)

In this study, nickel–aluminum bronze (NAB) is optimized by ultrasonic nanocrystal surface modification (UNSM), and its surface microstructural evolution, surface hardness, electrochemical corrosion behavior, and cavitation erosion behavior are investigated. The potentiodynamic polarization curves and electrochemical impedance spectra before and after UNSM treatment of NAB are measured using a typical three-electrode system. The cavitation erosion process is simulated through the vibration of ultrasonic waves underwater, and the cavitation erosion resistance performance of various specimens is evaluated. UNSM significantly refines the coarse and heterogeneous multi-phase structure of the cast NAB, providing a relatively uniform and dispersed structure. Simultaneously, severe plastic deformation rapidly increases micro-strains on the NAB surface, which effectively improves its surface hardness from 211 to 360 Hv. After UNSM treatment, the corrosion potential increases slightly; and the passivation potential and current decrease considerably, dropping from 207 to 103 mV and from 5.23 to 2.41 mA/cm2, respectively. This is primarily because of the slowdown of selective-phase corrosion and the uniform formation of an oxide film. Additionally, UNSM parameters affect corrosion potential by regulating surface roughness. A smoother surface corresponds to a higher corrosion potential at the same load. UNSM treatment significantly improves the cavitation corrosion resistance of NAB, primarily because an increase in hardness and uniform distribution of structure effectively slows the speed of crack formation and propagation, which is a result of the synergistic improvement of mechanical and corrosion resistance properties.

A facile and green alternative method for preconcentration of triazole fungicides using fabrication of melamine sponge anchoring with Ni/Al-LDH adsorbent followed by HPLC analysis

In this work, a facile and green alternative method for preconcentration of triazole fungicides (TFs) using melamine sponge anchoring with nickel/aluminium layered double hydroxide (Ni/Al-LDH-MS) as adsorbent for micro-solid phase extraction (micro-SPE). LDHs was prepared by nickel (II) nitrate hexahydrate and aluminium nitrate nonahydrate. The adsorbent was simply synthesized under facile condition via anchoring of Ni/Al-LDH on the pore of melamine sponge (MS). The material was applied for extraction of triazole fungicides prior to HPLC analysis. Under the chosen conditions, the proposed method provides wide linearity between 0.09 –1.00 µg L-1 with coefficients for determination (R2) of greater than 0.99. Low detection limits of 0.03 µg L-1 for all analytes were achieved. The satisfactory recoveries of the real samples at three different concentration levels were obtained in the range of 64.5 % to 105.6 % with RSDs lower than 7.5 %. The findings highlight the importance of developing efficient adsorbents for the enrichment of trace triazoles in surface water, soymilk, honey and egg yolk matrices. Eco-friendliness was confirmed by Analytical Eco-scale and Analytical GREEnness metric (AGREE) which shown that the recommended analytical procedure is more green than previous methods.

Fabrication of nickel aluminate based electrochemical sensor for dopamine detection

Nickel aluminate nanoparticles (NiAl2O4 NPs) spinel structure is synthesized via a simple solution combustion method using aqueous nickel nitrate, aluminum nitrate and citric acid. The crystal structure and microstructure of the prepared NiAl2O4 NPs are confirmed by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum, scanning and transmission electron microscopy (SEM/TEM). The characterized NiAl2O4 NPs are applied on a glassy carbon electrode (GCE) to design electrochemical sensor for the detection of dopamine (DA) using cyclic voltammograms (CV) and differential pulse anodic stripping voltammograms. The proposed electrochemical sensor exhibits excellent sensing activity with a low detection limit of 1.78 μM and applicable for a wide linear concentration range of 10 μM–140 μM. Further, the proposed electrode exhibits well resolved differential pulse voltammogram for the dopamine in presence of interfering uric acid and ascorbic acid.

Toward Reducing Casting Defects via 3D Risers via 3D Sand-Printing: A Simulation Study

AbstractThe 3D sand printing (3DSP) process is a binder jetting class of additive manufacturing process that can incorporate complex 3D mold designs and consolidate cores with intricate features that were previously inaccessible. Prior studies in 3DSP mold design have been shown to improve pouring and filling conditions for sand casting. However, the opportunity to improve casting quality by exploring 3D riser designs during the solidification stage has not yet been explored. In this research, three novel 3D riser geometries—ellipsoid, spherical, and a fusion riser (combination of cylindrical and ellipsoid riser) were investigated. The results were compared to the benchmark cylindrical risers to assess casting performance (e.g., reduction in shrinkage porosity, increase in solidification time). Computational solidification simulations have been presented to evaluate the characteristics of the novel risers for three different metal alloys- nickel aluminum bronze (NAB), low-carbon steel A216 (WCB), and aluminum alloy (A319) alloy. From the results of this research, spherical risers were found to provide 45% yield improvement of for the three alloys studied. In addition, the riser neck diameter using a spherical riser experienced up to 77% reduction when compared to the recommended dimensions from previous literature. Finally, one of the spherical riser designs provided 18% improvement in terms of riser-pipe safety height over the benchmark design. Findings from this research will help metalcasting industries to optimize their riser designs for complex casting geometries by implementing 3D riser geometries (via 3DSP) into traditional mold making for yield improvement and defect-free castings.

Enhancing biomass gasification: A comparative study of catalyst applications in updraft and modifiable-downdraft fixed bed reactors

This study aims to investigate the effects of different catalysts on biomass gasification. Therefore, red mud (RM) and Aluminum–Nickel alloy were used as catalysts with biomass mixture (BM) for the lab-scale gasification studies by using an updraft and a modifiable-downdraft fixed bed reactor. The maximum volumetric percentage of H2, ranging from 51% to 65%, was achieved at 900 °C in both gasifiers. Al–Ni catalyst significantly boosted H2 content, reaching 65% in the updraft gasifier at 900 °C with 0.05 L/min dry air. H2/CO ratio varied from 2 to 4 for BM, while catalyst use expanded the range to 1.6–7 with the Al–Ni catalyst demonstrating the most effective performance. In general, it was seen that RM increased the H2 component in the syngas between 1 and 7 vol% at 900 °C in updraft gasifier. In the modifiable-downdraft reactor, on the contrary, H2 concentration in the syngas decreased by 2–6% with the addition of RM.

Role of oscillation frequency and amplitude on the microstructure and properties of linear friction welded nickel aluminium bronze joints

This study explores the influence of oscillation frequency and amplitude on the quality of linear friction welded joints using as-cast nickel aluminium bronze. Welding was conducted at 30 Hz, 50 Hz, and 70 Hz oscillated frequencies and amplitudes of 1.5 mm, 2 mm, and 3 mm. The joint’s performance was thoroughly investigated through systematic analysis, including macrostructure examination, peak interfacial temperature measurement, microstructure evaluation, strain assessment, cooling rate determination, microhardness testing, and tensile property characterization. The width of the weld zone varied from 183 μm to 297 μm, and the thermomechanical affected zone (TMAZ) area ranged from 4.48 mm2 to 14.79 mm2 across different process parameters. In the parent material, the volume fraction of the β-phase was as low as 20.2%, contrasting with the dominant α-phase at 79.8%. The average grain size of the lamellar and globular α-phase mixture was 26.4 μm. Notably, the weld zone exhibited extremely refined α-phase grains, with diameters less than 5 μm in all cases. The volume fraction of the β‘-phase increased significantly with higher frequencies, from 15.299% at 30 Hz to 26.98% at 50 Hz, peaking at 40.08% at 70 Hz, leading to varying k phases. This variation in microstructure had a substantial impact on mechanical properties. Tensile strength ranged from 503 MPa to 582 MPa, while ductility varied from 13.5% to 21.7%. Additionally, the hardness of the parent material increased from approximately 155 Hv to 260 Hv. This study demonstrates that controlling the oscillation frequency and amplitude in linear friction welding processes can yield consistent, high-quality welds in nickel aluminium bronze.

Structural and optical properties of nickel aluminate spinel ferrite thin films prepared by spray pyrolysis technique

Structural and optical properties of nickel aluminate spinel ferrite thin films prepared by spray pyrolysis technique

Quantitative Analysis of Silicon Influence and Deformation Impact on the Mechanical and Corrosion Characteristics of Nickel Aluminium Bronze (NAB) Alloy

Nickel aluminum bronze (NAB) alloy has become increasingly popular due to its superior strength, corrosion resistance, and thermal properties. This study provides an in-depth analysis of the effect of silicon and deformation percentages on the mechanical and corrosion characteristics of NAB alloy, for marine and architectural applications. The research was carried out by systematically varying the silicon percentage (0-10%) while the percentage of deformation ranges from 0-10% at ambient temperature (32 oC), and subsequent changes in its mechanical properties and corrosion resistance were observed. Mechanical properties such as ultimate tensile strength, ductility, and hardness were evaluated using standard testing methods. The results indicated a significant correlation between the silicon percentage and the mechanical properties. Specifically, an increase in the silicon percentage was found to enhance the tensile strength from 190.7 MPa to 590.8 MPa, the ductility from 23.7% to 46.9% and the hardness from 130.5 HV to 262.4 HV values of the NAB alloy. The corrosion rate of 5.49 mm/a was obtained for the reference material containing 0% Si at 0% (X0-0) deformation, while the least corrosion rate of 9.8x10-5 mm/y was recorded for 2 wt. % Si at 10% deformation (X2-5). These findings have significant implications for the use of NAB alloy in marine and architectural applications. When the silicon percentage is optimized, the mechanical strength and corrosion resistance of the alloy are enhanced, thereby improving the durability and longevity of structures made from the developed NAB alloy

Effect of heat input on bead geometry and mechanical properties in wire arc additive manufacturing of a nickel aluminum bronze alloy

Wire arc additive manufacturing (WAAM) stands as an efficient and cost-effective method for producing large-scale engineering components while minimizing waste. This study explores the influence of WAAM process parameters on nickel aluminum bronze (NAB) parts, focusing on the wire feed rate (WFR) as a key factor governing heat input and its effects on bead geometry, microstructure, and mechanical properties. The investigation involved depositing a single bead from NAB alloy while varying the WFS within the 2–7 m/min range, resulting in heat inputs ranging from 20.600 to 57.960 kJ/m. The results revealed that increasing heat input up to 34.944 kJ/m led to an augmentation in the bead dimensions and increased hardness due to κ-precipitates formation within the α-Cu matrix. However, with further increments in heat input to 49.088 kJ/m and 57.960 kJ/m, the bead dimensions and hardness exhibited a decline as the uniformity of intermetallic κ distribution lessened. Through optimization of WAAM process parameters, a defect-free single-wall NAB was successfully manufactured with enhanced properties. The tensile strength along the horizontal direction for the single-wall NAB alloy was found to be superior to that of the vertical direction, irrespective of the specimen's extraction regions. Additionally, the bottom specimen exhibited slightly higher tensile strength than the center and upper specimens due to being the initial layers of the wall deposited on the substrate plate, undergoing a faster cooling rate. These findings underscore the potential of WAAM as a robust method for the fabrication of larger NAB components with precision and efficiency.

Single-Bubble Cavitation-Induced Pitting on Technical Alloys

Repeated single cavitation bubble experiments were performed primarily on 316L stainless steel, and some on nickel–aluminum–bronze (NAB) and pure aluminum. The bubble dynamics were recorded with two high-speed cameras and correlated with surface images, also acquired in situ. These experiments were performed for a range of stand-off distances γ (the ratio of the distance of the solid surface from the bubble to the bubble’s maximum radius) from 0.3 to 2.15. For all stand-off distances, single pits were the only surface change detected at the beginning of damage formation. Later phases of the collapse are not axisymmetric but show regions of “stronger” collapse, and the pits occur on the material underneath those regions. For γ < 0.4, the damage is attributed to the second collapse. For γ > 0.4, the first bubble collapse is most likely responsible for pitting. Shock-wave emission was detected from the collapse regions that were linked to the damage. On 316L, the pitting rate was found to be linearly dependent on the bubble radius, indicating a non-zero lower limit for the bubble radius below which pits do not occur. In terms of stand-off distance, the pitting rate (defined here as average pits per bubble) was non-monotonic, with maxima for bubbles initiated closest to the sample (γ = 0.3) and at γ = 1.4.

Investigation of ballistic and mechanical properties of AlNPB metal matrix composites reinforced with TiCN decorated graphene nano flakes for light armored vehicles

In response to evolving military strategies and technology advancements, this study investigates the ballistic and mechanical properties of novel defense grade Aluminium Nickel Phosphorized Bronze (AlNPB) Metal Matrix Composites (MMCs) reinforced with 2, 4, and 6 wt% of Titanium Carbonitride (TiCN) decorated graphene nanoflakes (TG NPs). The TG NPs were synthesized via modified Hummer's method, mechanically milled with TiCN, and integrated into the AlNPB matrix through the stir casting technique. The fabricated MMCs were characterized using XRD, FTIR, and SEM analyses to evaluate the formation of the nanocomposite and MMC. A series of mechanical tests, including tensile, impact, and compression analyses, identified 4 wt% as the optimum filler loading to enhance mechanical strength. The corrosion resistance of the MMCs was studied alongside their morphological analysis. Explicit ballistic tests yielded satisfactory results, bolstering the potential of the fabricated MMCs for use in Light Armored Vehicles (LAVs). This research contributes a valuable MMC candidate for enhancing the performance and durability of LAVs in challenging environments.

Observation of the formation of CuAl2O4 by the direct consumption of Al2O3 in an NAB alloy at elevated temperature

The oxidation behaviors of a commercial C95500 nickel aluminum bronze (NAB) alloy at elevated temperatures were investigated. The oxide scale exhibited a triplex structure with an outmost CuAl2O4 layer, an intermediate spinel-type Al2O3 layer, and a deepest nano Al2O3 film. The observation of CuAl2O4 and Al2O3 in the same grain with the same crystallographic orientation indicated that the outmost CuAl2O4 was formed by directly consuming the spinel-type Al2O3. Such a transformation process can avoid the formation of defects in the oxide scale caused by the transformation between different Al2O3 variants, attributing to the origin of the excellent oxidation resistance.

Electro-optical properties of solution-processed aluminum–nickel oxide film containing graphene oxide in liquid crystal system

Electro-optical properties of solution-processed aluminum–nickel oxide film containing graphene oxide in liquid crystal system

Efficient synthesis of γ-valerolactone from ethyl levulinate via catalytic transfer hydrogenation in supercritical isopropanol over nickel aluminum oxide nanosheets

This study reports a novel method for γ-valerolactone (GVL) production from ethyl levulinate (EL) utilizing non-noble metal catalysts within a supercritical isopropanol (IPA) system. Nickel-loaded nickel–aluminum oxide nanosheets (NiXAl-R) were fabricated via hydrothermal treatment of Ni–Al layered double hydroxide precursors, followed by hydrogen reduction at 550 °C for 1.5 h. Using NiXAl-R as the catalyst and IPA as the hydrogen donor, we achieved notable results: 82.7% EL conversion, 73.6% GVL yield, and 1.178 molGVL g−1 h−1 reaction efficiency after 1.5 h in supercritical IPA. The catalytic activity of NiXAl-R remained stable over five catalytic cycles. The surface of NiXAl-R exhibits abundant oxygen vacancies and unsaturated Al species (Alx+), which promote the initial transfer hydrogenation of EL to form the ethyl 4-hydroxypentanoate (4-HPE) intermediate. Simultaneously, the supercritical IPA environment overcomes mass transfer limitations at the solid–liquid interface between 4-HPE and the catalyst, thereby facilitating the Alx+-catalyzed intramolecular esterification of 4-HPE into GVL.

Preparation of nickel aluminate supported Ni nanocatalyst and its catalytic activity for ammonia decomposition to produce hydrogen

In this work, nickel aluminate (NiAl2O4) was synthesized through the co-precipitation, and then the Ni/NiAl2O4 catalysts were prepared by impregnation and the catalytic activity of the catalyst was evaluated. The results indicated that the synthesized NiAl2O4 had a large specific surface area, promoting the dispersion of Ni species and thus exposing more active sites. The strong metal-support interaction between Ni species and NiAl2O4 contributed significantly to the catalysts' high catalytic activity. Meanwhile, the strong basicity of catalyst could adjust the bond energy of Ni–N, which were conducive to desorption of the recombinant N2 from the metal surface. The Ni/NiAl2O4 catalyst with Ni loading of 50 wt% and calcination temperature of 700 oC exhibited the best catalytic activity with ammonia conversion of 95.3% at 550 oC under 30000 mL∙gcat-1∙h-1. This study offers a potential approach to developing a cost-effective and highly efficient catalyst for decomposing ammonia.

Corrosion mechanisms of plasma welded Nickel aluminium bronze immersed in seawater

Nickel Aluminium Bronzes (NAB) are copper-based multi-phase alloys used extensively in marine applications. NAB is vulnerable to seawater corrosion, however the interaction between its corrosion mechanisms and real-world factors including biofouling, weld microstructure and residual stress are poorly understood. Seawater corrosion tests were performed on plasma-welded NAB in laboratory and marine environments, demonstrating that the retained β’ phase in the Heat Affected Zone (HAZ) experiences Selective Phase Corrosion (SPC), whereas crevice corrosion associated with SPC of the κIII phase occurs at biofouled and stressed areas of parent material. These factors, seldom simulated in physical tests, severely impact NAB’s corrosion resistance.

Pore form and size dependence on plastic joining characteristics of resin/metallic foam by friction stir incremental forming

A metallic foam specimen was plastically joined with a resin (polymethyl methacrylate, PMMA) sheet by applying friction stir incremental forming (FSIF) process. In FSIF process, a rotating flat-ended (no probe) rod tool was pushed vertically and fed horizontally against the resin sheet which was placed on the foam. The tool operation heated frictionally the resin and deformed incrementally to the resin, while the tool operation did not deform plastically to the cellular matrix of the foam. Due to the plastic flow of the heated resin, the bottom of the resin was interlocked mechanically to the pores near the top surface of the foam. In this study, the relationship between the pore morphology (form and size) and the joining characteristics (joinability, flow thickness of the resin, and joining strength) was investigated using commercial open-cell nickel and closed-cell aluminum foams. According to the experimental investigations, the foam with small size and low depression angle of the surface pore showed better results in relation with the joining strength and the (flow thickness of the resin)/(depth of the surface pore).

Biofouling and corrosion rate of welded Nickel Aluminium Bronze in natural and simulated seawater

Updated understanding on the effect of biofouling on corrosion rate is needed to protect marine structures as climate change is altering seawater physiochemistry and biofouling organism distribution. Multi-disciplinary techniques can improve understanding of biofouling development and associated corrosion rates on metals immersed in natural seawater (NSW). In this study, the development of biofouling and corrosion on welded Nickel Aluminium Bronze (NAB) was investigated through long-term immersion tests in NSW, simulated seawater (SSW) and air. Biofouling was affected by geographic location within the marina and influenced corrosion extent. The corrosion rate of NAB was accelerated in the initial months of exposure in NSW (1.27 mm.yr−1) and then settled to 0.11 mm.yr−1 (annual average). This was significantly higher than the 0.06 mm.yr−1 corrosion rate measured in SSW, which matched published rates. The results suggest that corrosion rates for cast NAB should be revised to take account of biofouling and updated seawater physiochemistry.

Effect of liquid nitrogen cryogenic cooling during wire arc directed energy deposition of nickel aluminum bronze

Effect of liquid nitrogen cryogenic cooling during wire arc directed energy deposition of nickel aluminum bronze

Perspectives on the unusual electrochemical corrosion of Nickel Aluminum Bronze (NAB) alloy fabricated through laser-powder bed fusion additive manufacturing

This research delves into the passivation and electrochemical corrosion response of as-printed and annealed L-PBF NAB, comparing their performance with wrought NAB counterparts. The results unveil that the interplay between microstructural uniformity, higher aluminum content, residual stress, and the presence of martensitic nanotwins substantially enhances the integrity of the corrosion film and improves the uniform corrosion resistance of as-fabricated NAB. Nonetheless, this combination adversely impacts the localized corrosion resistance. Remarkably, annealing, despite its detrimental effect on passivation and uniform corrosion behavior, ameliorates resistance to localized attacks. In contrast, the wrought equivalents exhibit inferior electrochemical corrosion performance across all experimental conditions.