Combustion Synthesis and Consolidation of Ni-W Nanocomposite Material

Zakaryan, Marieta K.; Aydinyan, Sofiya; Kharatyan, S. L.

doi:10.29272/cmt.2018.0007

Cited by 5 publications

(8 citation statements)

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“…In (NiO-WO 3 -Mg-C) and (NiWO 4 -Mg-C) systems, the reducers' ratio was chosen based on the preliminary experimental results, considering that high amounts of magnesium induces an explosive reaction, whereas a high amount of carbon makes the interaction self-inhibited [13,15,30]. Based on the foregoing observations, NiO + WO 3 + 2.5Mg + 1.5C and NiWO 4 + 2Mg + 2C compositions were selected, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Energy saving self-propagating high-temperature synthesis (SHS), known also as combustion synthesis (CS), provides a technological advance for the synthesis of a great number of materials (metal powders, alloys and nanocomposites) of high purity and allows control over the combustion process parameters, regulation of the powder grain size and maintenance of compositional homogeneity. SHS has already successful performed the reduction of oxides and salts of distinctly different metals at moderate temperature mode using (Mg + C) combined reducer via a reactions' coupling approach [13][14][15][16]. In addition, the joint reduction of oxygenous compounds of Ni and W metals is also of significant practical interest in terms of in situ preparation of fine and homogeneous Ni-W composite powder.…”

Section: Introductionmentioning

confidence: 99%

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Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

Zakaryan

Nazaretyan

Aydinyan

et al. 2021

Metals

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Functional features of Ni-W composite materials combined with successful performance enabled a breakthrough in their broad application. To disclose the formation pathway of Ni-W composite materials at extreme conditions of combustion synthesis in the NiO-WO3-Mg-C and NiWO4-Mg-C systems for the optimization of the synthesis procedure, the process was modeled under programmed linear heating conditions by thermal analysis methods. The reduction kinetics of tungsten and nickel oxides mixture and nickel tungstate by Mg + C combined reducer at non-isothermal conditions was studied at high heating rates (100–1200 °C min−1) by high-speed temperature scanner techniques. It was shown that when moving from low heating to high heating rates, the mechanism of both the magnesiothermic and magnesio-carbothermic reductions of the initial mixtures changes; that is, the transition from a solid-solid scheme to a solid-liquid scheme is observed. The strong influence of the heating rate on the reduction degree and kinetic parameters of the systems under study was affirmed. The simultaneous utilization of magnesium and carbon as reducers allowed the lowering of the starting and maximum temperatures of reduction processes, as evidenced by the synergetic effect at the utilization of a combined reducer. The effective values of activation energy (Ea) for the reactions proceeding in the mixtures NiO + WO3 + 4Mg, NiO + WO3 + 2.5Mg + 1.5C, NiWO4 + 4Mg and NiWO4 + 2Mg + 2C were estimated by Kissinger isoconversional method and were 146 ± 10, 141 ± 10, 216 ± 15 and 148 ± 15 kJ mol−1, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

Zakaryan

Nazaretyan

Aydinyan

et al. 2021

Metals

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“…Nickel (II) oxide (Alfa Aesar, >99%, <44 μm), tungsten (VI) oxide (High grade, Krasniy khimik, Ukraine, <40 µm), carbon black (P-803, Russia, <1 µm) and magnesium (MPF-3, Russia, 150–300 µm) were used to prepare Ni-W powders in combustion experiments. Thermodynamic calculations in the NiO-WO 3 -yMg-xC system demonstrated that the formation of a target product (Ni:W = 1:1 molar ratio) is achievable in a certain amount of carbon (from 1.6 to 2.3 mol) and magnesium (from 1.7 to 2.2 mol) at a 1000–2000 °C adiabatic temperature interval, allowing to design the optimum synthesis circumstances for the simultaneous and entire reduction of tungsten and nickel oxides in a wide range of compositions and thermal conditions ( Figure 1 ) [ 26 ]. The probable formation of tungsten carbides (WC and W 2 C) was ruled out during the thermodynamic calculations.…”

Section: The Role Of Coupling On the Synthesis And Sintering Of Shs Powdersmentioning

confidence: 99%

“…By the same token, the magnesio-carbothermic combined reduction of WO 3 and NiO was performed via changing the amount of carbon within a prescribed range, in accordance with the TC predicted area. It was revealed that the increase in the carbon amount is responsible for the reduction in the combustion parameters (temperature and velocity), conditioned by a consistent increase in the contribution of the low-caloric carbothermic reaction in the system in one hand, and the change in the interaction mechanism in another [ 26 ]. Specifically, at a low amount of carbon, molten NiO participates in the process, and at a high carbon content, solid NiO participates in the process.…”

Section: The Role Of Coupling On the Synthesis And Sintering Of Shs Powdersmentioning

confidence: 99%

“…Note that two different combustion modes were observed, according to the carbon amount in the NiO-WO 3 -yMg-xC system: a steady state (with a carbon amount of around 2.2 mol) and an unsteady mode at a high-carbon content (5 mol). The latter corresponds to the spin combustion mode, demonstrating a change in both the microstructure and phase composition of the products [ 26 ].…”

Section: The Role Of Coupling On the Synthesis And Sintering Of Shs Powdersmentioning

confidence: 99%

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SHS-Derived Powders by Reactions’ Coupling as Primary Products for Subsequent Consolidation

2021

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The capability of self-propagating high-temperature synthesis (SHS) to produce powders that are characterized by a high sintering ability, owing to high heating and cooling rates inherent to the exothermic reaction, is of a special interest for the industry. In particular, SHS-derived powders comprise a significant defect concentration in order to effectively enhance the mass transfer processes during the sintering, which allows for the successful consolidation of difficult-to-sinter materials at relatively low sintering temperatures. From this perspective, the design of precursors suitable for sintering, synthesis in a controlled temperature regime and the optimization of geometrical and structural parameters of SHS powders as a potential feedstock for the consolidation is of key importance. Here, we report on the comparative studies concerning the SHS processing of composites for advanced powder metallurgy techniques. The synthesis and sintering peculiarities of the SHS through coupled reactions in the Me’O3(WO3,MoO3)-Me’’O(CuO,NiO)-Mg-C, Ti-B-Al12Mg17 systems are comparatively reviewed. The SHS coupling approach was used for the preparation of powders with a tuned degree of fineness (a high specific surface area of particles), a high-homogeneity and a controllable distribution of elements via both the regulation of the thermal regime of combustion in a wide range and the matching of the thermal and kinetic requirements of two interconnected reactions. Microstructural features of the powder feedstock greatly contributed to the subsequent consolidation process.

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

et al. 2022

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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.

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Combustion Synthesis and Consolidation of Ni-W Nanocomposite Material

Cited by 5 publications

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Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

SHS-Derived Powders by Reactions’ Coupling as Primary Products for Subsequent Consolidation

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

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