Peculiarities of the neck growth process during initial stage of spark-plasma, microwave and conventional sintering of WC spheres

Dmytro Demirskyi, Hanna Borodianska, Dinesh Kumar Agrawal, Andrey Ragulya, Yoshio Sakka, Oleg Vasylkiv

Research output: Contribution to journalArticle

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Abstract

This work involves an investigation of the neck growth kinetics of free-packed spherical shaped binderless tungsten carbide particles during microwave and spark-plasma sintering. The application of a classical sphere to sphere approach showed the possibility of identifying the main diffusion mechanisms operating during the initial stage of microwave sintering of tungsten carbide powder. An anomalous neck growth rate in the initial period during microwave and spark-plasma sintering processes, up to 100 times faster in comparison to conventional sintering, was also revealed. Volume diffusion was enhanced by a small amount of a liquid phase, and surface diffusion was proposed as the primary mass transport mechanism for microwave sintering. The simulation operation of grain-boundary diffusion and power law creep was responsible for neck growth during spark-plasma sintering. Numerical simulation of neck growth revealed high values of the diffusion coefficient for microwave (3.41 × 10 -8 m 2 s -1 at 1200 °C) and spark-plasma sintering (5.41 × 10 -8 m 2 s -1 at 1200 °C). In the case of conventional sintering, the diffusion coefficients calculated are in good agreement with values for diffusion of W and C in a W-C system (8.6 × 10 -16 m 2 s -1 at 1200 °C). Low values of the apparent activation energy (E a) for microwave and spark-plasma sintering (62 and 52 kJ mol -1) have been obtained. For conventional sintering, all data collected indicate grain-boundary diffusion as the primary sintering mechanism (272 kJ mol -1).

Original languageEnglish (US)
Pages (from-to)1-10
Number of pages10
JournalJournal of Alloys and Compounds
Volume523
DOIs
StatePublished - May 15 2012

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Electric sparks
Spark plasma sintering
Sintering
Microwaves
Plasmas
Tungsten carbide
Grain boundaries
Surface diffusion
Growth kinetics
Powders
Creep
Mass transfer
Activation energy
Computer simulation
Liquids

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

Demirskyi, Dmytro ; Borodianska, Hanna ; Agrawal, Dinesh Kumar ; Ragulya, Andrey ; Sakka, Yoshio ; Vasylkiv, Oleg. / Peculiarities of the neck growth process during initial stage of spark-plasma, microwave and conventional sintering of WC spheres. In: Journal of Alloys and Compounds. 2012 ; Vol. 523. pp. 1-10.
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abstract = "This work involves an investigation of the neck growth kinetics of free-packed spherical shaped binderless tungsten carbide particles during microwave and spark-plasma sintering. The application of a classical sphere to sphere approach showed the possibility of identifying the main diffusion mechanisms operating during the initial stage of microwave sintering of tungsten carbide powder. An anomalous neck growth rate in the initial period during microwave and spark-plasma sintering processes, up to 100 times faster in comparison to conventional sintering, was also revealed. Volume diffusion was enhanced by a small amount of a liquid phase, and surface diffusion was proposed as the primary mass transport mechanism for microwave sintering. The simulation operation of grain-boundary diffusion and power law creep was responsible for neck growth during spark-plasma sintering. Numerical simulation of neck growth revealed high values of the diffusion coefficient for microwave (3.41 × 10 -8 m 2 s -1 at 1200 °C) and spark-plasma sintering (5.41 × 10 -8 m 2 s -1 at 1200 °C). In the case of conventional sintering, the diffusion coefficients calculated are in good agreement with values for diffusion of W and C in a W-C system (8.6 × 10 -16 m 2 s -1 at 1200 °C). Low values of the apparent activation energy (E a) for microwave and spark-plasma sintering (62 and 52 kJ mol -1) have been obtained. For conventional sintering, all data collected indicate grain-boundary diffusion as the primary sintering mechanism (272 kJ mol -1).",
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Peculiarities of the neck growth process during initial stage of spark-plasma, microwave and conventional sintering of WC spheres. / Demirskyi, Dmytro; Borodianska, Hanna; Agrawal, Dinesh Kumar; Ragulya, Andrey; Sakka, Yoshio; Vasylkiv, Oleg.

In: Journal of Alloys and Compounds, Vol. 523, 15.05.2012, p. 1-10.

Research output: Contribution to journalArticle

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AU - Demirskyi, Dmytro

AU - Borodianska, Hanna

AU - Agrawal, Dinesh Kumar

AU - Ragulya, Andrey

AU - Sakka, Yoshio

AU - Vasylkiv, Oleg

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N2 - This work involves an investigation of the neck growth kinetics of free-packed spherical shaped binderless tungsten carbide particles during microwave and spark-plasma sintering. The application of a classical sphere to sphere approach showed the possibility of identifying the main diffusion mechanisms operating during the initial stage of microwave sintering of tungsten carbide powder. An anomalous neck growth rate in the initial period during microwave and spark-plasma sintering processes, up to 100 times faster in comparison to conventional sintering, was also revealed. Volume diffusion was enhanced by a small amount of a liquid phase, and surface diffusion was proposed as the primary mass transport mechanism for microwave sintering. The simulation operation of grain-boundary diffusion and power law creep was responsible for neck growth during spark-plasma sintering. Numerical simulation of neck growth revealed high values of the diffusion coefficient for microwave (3.41 × 10 -8 m 2 s -1 at 1200 °C) and spark-plasma sintering (5.41 × 10 -8 m 2 s -1 at 1200 °C). In the case of conventional sintering, the diffusion coefficients calculated are in good agreement with values for diffusion of W and C in a W-C system (8.6 × 10 -16 m 2 s -1 at 1200 °C). Low values of the apparent activation energy (E a) for microwave and spark-plasma sintering (62 and 52 kJ mol -1) have been obtained. For conventional sintering, all data collected indicate grain-boundary diffusion as the primary sintering mechanism (272 kJ mol -1).

AB - This work involves an investigation of the neck growth kinetics of free-packed spherical shaped binderless tungsten carbide particles during microwave and spark-plasma sintering. The application of a classical sphere to sphere approach showed the possibility of identifying the main diffusion mechanisms operating during the initial stage of microwave sintering of tungsten carbide powder. An anomalous neck growth rate in the initial period during microwave and spark-plasma sintering processes, up to 100 times faster in comparison to conventional sintering, was also revealed. Volume diffusion was enhanced by a small amount of a liquid phase, and surface diffusion was proposed as the primary mass transport mechanism for microwave sintering. The simulation operation of grain-boundary diffusion and power law creep was responsible for neck growth during spark-plasma sintering. Numerical simulation of neck growth revealed high values of the diffusion coefficient for microwave (3.41 × 10 -8 m 2 s -1 at 1200 °C) and spark-plasma sintering (5.41 × 10 -8 m 2 s -1 at 1200 °C). In the case of conventional sintering, the diffusion coefficients calculated are in good agreement with values for diffusion of W and C in a W-C system (8.6 × 10 -16 m 2 s -1 at 1200 °C). Low values of the apparent activation energy (E a) for microwave and spark-plasma sintering (62 and 52 kJ mol -1) have been obtained. For conventional sintering, all data collected indicate grain-boundary diffusion as the primary sintering mechanism (272 kJ mol -1).

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