Mo–Cu pseudoalloys by combustion synthesis and spark plasma sintering

Minasyan, Tatevik; Kirakosyan, H.; Aydinyan, Sofiya; Liu, Le; Kharatyan, S. L.; Hussainova, Irina

doi:10.1007/s10853-018-2787-1

Cited by 16 publications

(11 citation statements)

References 22 publications

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“…A similar approach was utilized for the preparation of the Mo-Cu bimetallic system from copper molybdates derived by calcination (I) and coprecipitation (II) methods, with a subsequent consolidation [ 34 ].…”

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

confidence: 99%

“…Accordingly, the corresponding mixtures with both salts, CuMoO 4 (I) + 1.2Mg + 2.2C and CuMoO 4 (II) + 1.5Mg + 1.6C, were selected for Mo-Cu alloy preparation. Despite the different amounts of reducers in the reactive mixture, both salts followed a similar reduction pathway, firstly converting into salts of Cu 2 MoO 5 and Cu 6 Mo 5 O 18 , then Cu and MoO 2 by carbon, and, at the end, into molybdenum by the magnesiothermic reduction of MoO 2 [ 34 ].…”

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

confidence: 99%

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

confidence: 99%

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

2021

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“…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%

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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“…Self-propagating exothermic reaction (SHS) for synthesizing composite materials and intermetallic compounds has shown its effectiveness in providing predisposition for reactive bonding of various metals due to the released energy capable of melting adjacent particles followed by subsequent solidification and creating favorable conditions for solid joints [5][6][7]. Moreover, the in-situ preparation of Mo-Cu composite powder by coreduction of metal oxide precursors in SHS process via reaction's coupling approach was demonstrated recently [8,9]. The mechanism and kinetics of reactions in the MoO3-CuO-Mg-C system has been investigated at non-isothermal conditions by DTA/TG method at low heating rates [10].…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of Joint Reduction of MoO3 and CuO by Combined Mg/C Reducer at High Heating Rates

Kirakosyan¹,

Nazaretyan²,

Aydinyan³

et al. 2021

Preprint

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Understanding of the decisive role of the interaction mechanism and kinetics in the combustion processes is highly relevant for the elaboration of optimal conditions for obtaining Mo-Cu composite powders. From this perspective, the efficient delivery of the reduction mechanism of copper and molybdenum oxides with combined Mg + C reducing agents at high heating rates is crucial to develop a valuable approach for the combustion synthesis of Mo-Cu composite powders. Herein, we shed light on the mechanism of the reactions in all the studied binary, ternary and quaternary systems contemporaneously demonstrating the effect of the heating rate on the conversion degree. The combination of two highly exothermic and speedy reactions (MoO3+3Mg and CuO+Mg vs MoO3+CuO+4Mg) led to a slow interaction with weak self-heating (dysynergistic effect) due to a change in the reaction mechanism. On the other hand, it has been shown that during the simultaneous utilization of the Mg and C reducing agents, the process begins exclusively with carbothermic reduction, and at relatively high temperatures it continues with magnesiothermic one. The effective activation energy values of the magnesiothermic stages of the studied reactions were determined by Kissinger isoconversional method.

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Mo–Cu pseudoalloys by combustion synthesis and spark plasma sintering

Cited by 16 publications

References 22 publications

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

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

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

The Mechanism of Joint Reduction of MoO3 and CuO by Combined Mg/C Reducer at High Heating Rates

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