Microwave Heating of Pure Copper Powder with Varying Particle Size and Porosity

Mondal, Avijit; Agrawal, Dinesh Kumar; Upadhyaya, Anish

doi:10.1080/08327823.2008.11688599

Cited by 73 publications

(44 citation statements)

References 1 publication

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“…However, most of these works were dealing with either heating of metals [7] or later stages of sintering [8], those are usually similar to those for conventional sintering [9]. The results that have been recently revealed on initial stage of microwave sintering [10], confirmed that during microwave heat treatment of metals the neck formation process may be started during heating, or soaking for few seconds in case of processing in pure E or H field [6].…”

Section: Introductionmentioning

confidence: 52%

Neck growth kinetics during microwave sintering of nickel powder

Demirskyi

Agrawal

Ragulya

2011

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 52%

Neck growth kinetics during microwave sintering of nickel powder

Demirskyi

Agrawal

Ragulya

2011

Journal of Alloys and Compounds

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“…6 When providing a catalyst for reaction, it is necessary also to consider how energy is supplied to the catalyst surface, in particular because the efficiency of this process is governed by classical heat-transfer limitations. However, metal catalysts are known to absorb energy rapidly under microwave irradiation and, as a result, to couple the microwave energy selectively to the catalyst particles, leaving the surrounding environment less or even unheated [54][55][56][57]. In this way, microwaves selectively heat the reaction system at the locus of the reaction and so enhance efficiency as well as activity and conversion.…”

Section: Methodsmentioning

confidence: 99%

“…The difference in yield between microwave and conductive heating experiments can be attributed to the differential absorption of energy by the catalyst and liquid reaction mixture [54]. Thus, better yields are recorded for microwave heated experiments because higher temperatures are obtained at the locus of the reaction (i.e.…”

Section: Figurementioning

confidence: 99%

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Benaskar

Patil

Engels

et al. 2012

Chemical Engineering Journal

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The combination of milli-scale processing and microwave heating has been investigated for the Cu-catalyzed Ullmann etherification in fine-chemical synthesis, providing improved catalytic activity and selective catalyst heating. Wall-coated and fixed-bed milli-reactors were designed and applied in the Cu-catalyzed Ullmann-type C-O coupling of phenol and 4-chloropyridine. In a batch reactor the results show clearly increased yields for the microwave heated process at low microwave powers, whereas high powers and catalyst loadings reduced the benefits of microwave heating. Slightly higher yields were found in the Cu/ZnO wallcoated as compared to the Cu/TiO 2 fixed-bed flow-reactor. The benefit here is that the reaction occurs at the surface of the metal nanoparticles confined within a support film making the nano-copper equally accessible. Catalyst deactivation was mainly caused by Cu oxidation and coke formation; however, at longer process times leaching played a significant role. Catalyst 2 activity could partially be recovered by removal of deposited by-product by means of calcination. After 6 h on-stream the reactor productivities were 28.3 and 55.1 kg prod /(m R 3 •hr)for the fresh Cu/ZnO wall-coated and Cu/TiO 2 fixed-bed reactor, respectively. Comparison of single-and multimode microwaves showed a three-fold yield increase for single-mode microwaves. Control of nanoparticles size and loading allows to avoid high temperatures in a single-mode microwave field and provides a novel solution to a major problem for combining metal catalysis and microwave heating. Catalyst stability appeared to be more important and provided two-fold yield increase for the CuZn/TiO 2 catalyst as compared to the Cu/TiO 2 catalyst due to stabilized copper by preferential oxidation of the zinc. For this catalyst a threefold yield increase was observed in single-mode microwaves which, to the best of our knowledge, led to a not yet reported productivity of 172 kg prod /(m R 3 •hr) for the microwave and flow Ullmann C-O coupling.

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“…This heating mechanism is advantageous due to the following facts: (i) enhanced diffusion processes, (ii) reduced energy consumption, (iii) very rapid heating rates and considerably reduced processing times, (iv) decreased sintering temperatures, (v) improved physical and mechanical properties, (vi) simplicity, (vii) unique properties, and (viii) lower environmental hazards. These are features that have not been observed in conventional processes [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 93%

“…There are challenging demands from the PM industry for new and improved sintering process with finer microstructures and enhanced physical and mechanical properties. This is where the microwave technology is found to be advantageous [7].…”

Section: Introductionmentioning

confidence: 99%

Electrical and Mechanical Properties of Microwave Sintered Cu-ZrO2 (8-YSZ) Nano-Composites

Khaloobagheri¹

2015

IJMSA

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Abstract:Metal matrix nano-composites containing copper and ZrO 2 (8-YSZ) were sintered by microwave using mixtures of Cu and 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.% and 5 wt.% of zirconia powders for 20min. The zirconia content up to 5 wt.%, resulted in an increase of 62.5% and 21.9% in micro-hardness and compressive strength respectively, and slight decrease in relative density and electrical conductivity (% IACS). In addition, field emission scanning electron micros copy (FESEM) and SEM fitted with EDX were used to characterize the sintered nano-composites.

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Microwave Heating of Pure Copper Powder with Varying Particle Size and Porosity

Cited by 73 publications

References 1 publication

Neck growth kinetics during microwave sintering of nickel powder

Neck growth kinetics during microwave sintering of nickel powder

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Electrical and Mechanical Properties of Microwave Sintered Cu-ZrO2 (8-YSZ) Nano-Composites

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