Sintering iron using a hollow cathode discharge

Brunatto, Sílvio Francisco; Kühn, Ingeborg; Klein, Aloı́sio Nelmo; Muzart, J.L.R.

doi:10.1016/s0921-5093(02)00383-0

Cited by 23 publications

(22 citation statements)

References 14 publications

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“…Here, the heating of the part to the sintering temperature is carried out by the fast plasma species bombardment, and the part to be sintered acts as one cathode of the formed hollow cathode discharge. This situation is illustrated in the bottom of Figure 4, in which cylindrical parts to be sintered act as the inner cathode of a typical annular hollow cathode discharge, as presented in references [17][18][19][20][21][22][23]. It is to be noted that, for this configuration, plasma is much more ionized than that obtained in cathode configuration.…”

Section: (B)mentioning

confidence: 94%

“…In hollow cathode configuration, for a gas mixture composed of 80% Ar + 20% H 2 , the pressure range usually varies from 1 (133 Pa) to 9 (1200 Pa) Torr, considering pulse voltages on the order of 450 V [5,6,[17][18][19][20][21][22][23]. Here, the heating of the part to the sintering temperature is carried out by the fast plasma species bombardment, and the part to be sintered acts as one cathode of the formed hollow cathode discharge.…”

Section: (B)mentioning

confidence: 99%

“…For the cathode configuration, the cylindrical external (hollow) cathode was simply removed, thus leading to a heating condition where only one cathode (the central one) was present in the discharge. For more details, the reader can access the references [17][18][19][20][21][22][23]. In all cases, temperature increment can be expected as the switched-on time of the power supply, and thus the mean power transferred to the plasma is increased.…”

Section: Application Of Direct Current Plasma Sintering Process In Pomentioning

confidence: 99%

See 2 more Smart Citations

Application of Direct Current Plasma Sintering Process in Powder Metallurgy

Brunatto¹,

Cardoso²,

NelmoKlein³

2017

Powder Metallurgy - Fundamentals and Case Studies

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Direct current (dc) plasma-assisted sintering of metal parts is a promising and relatively new research and development field in powder metallurgy (PM). In the present entry, it is intended to introduce the reader to the main applications of the dc plasma sintering process in PM. To achieve this goal, the present entry is divided in a brief introduction and sections in which the bases of the dc plasma abnormal glow discharge regime and its influence in the sintering process are carefully treated. In this case, a clear language is purposely used to didactically introduce the reader to this "fascinating glow world", the dc plasma-assisted sintering of metal parts, aiming to put in evidence the main points on physicochemical aspects of the plasma environment, basic knowledge of the plasma heating, and surface-related phenomena during dc plasma sintering of parts.All these aspects are treated considering the main techniques of the dc plasma-assisted sintering process applied to PM. Finally, some results on DC plasma heating, sintering and surface modification are presented.

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Section: (B)mentioning

confidence: 94%

Section: (B)mentioning

confidence: 99%

Section: Application Of Direct Current Plasma Sintering Process In Pomentioning

confidence: 99%

See 1 more Smart Citation

Application of Direct Current Plasma Sintering Process in Powder Metallurgy

Brunatto¹,

Cardoso²,

NelmoKlein³

2017

Powder Metallurgy - Fundamentals and Case Studies

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“…In this process, the efficiency is attributed to the heat transfer mechanisms and to the reactivity of the environment that surrounds the sample 7 . Studies carried out on sintering pure iron in abnormal luminescent discharge suggest that the plasma produced in argon and hydrogen environment acts reducing the oxides existing in the surface of the particles that constitute the sample [8][9][10][11][12] . In this technique, the sample is placed on one of the electrodes (cathode or anode).…”

Section: Introductionmentioning

confidence: 99%

Sintering unalloyed titanium in DC electrical abnormal glow discharge

et al. 2010

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Powder metallurgy is widely used in the manufacture of components that have complex geometry. The good dimensional control, reduction in manufacturing steps and operating costs which has favored the use of this technique for manufacturing of titanium alloys components. However, the high affinity of this material with oxygen hinders strongly the sintering process. For this, the sintering associated with plasma technology can be considered an alternative technique for the processing of this material. The strict control of sintering atmosphere performed at low pressures and the reactive species present in the plasma environment can help to improve the sintering of this material. The results presented in this paper show a good correlation between the parameters used for the compaction of the samples and the microstructure develop during the plasma sintering of samples. The microstructure of the plasma assisted samples is also affected by the particular configuration used in the plasma reactor.

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“…This localized heating accelerates the formation of necks, leading to the activation of sintering. The application of plasma technology on powder metallurgy processing is mainly used for surface treatment [24][25][26][27] , cleaning 28 or sintering [29][30][31][32][33] . In these papers, an abnormal glow discharge of a gas mixture constituted of argon, hydrogen, nitrogen and methane was used.…”

Section: Introductionmentioning

confidence: 99%

Plasma sintering of unalloyed iron: a study of surface porosity

et al. 2004

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Samples of unalloyed iron powder were compacted and sintered in an abnormal glow discharge, generated in a gas mixture of 80% Ar + 20% H 2 by using a pulsed power source. The samples were placed on a holder, acting as the discharge cathode, and were heated by the bombardment of ions, strongly accelerated in the cathode sheath. Sintering was performed at temperatures of 1173, 1273 and 1373 K for 30 min, varying the voltage applied to the cathode from 400 to 700 V and pressure ranging from 470 to 2650 Pa. It is shown that the kinetic energy of ions striking the sample surface increased approximately three times, when the voltage changed from 400 to 700 V, with a corresponding reduction of surface porosity. The surface sealing is related to the ion bombardment, which produced a high mobility of surface atoms and consequent enhanced diffusion as well as sputtering and condensation on the concave surface, resulting in an activation of surface sintering.

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Sintering iron using a hollow cathode discharge

Cited by 23 publications

References 14 publications

Application of Direct Current Plasma Sintering Process in Powder Metallurgy

Application of Direct Current Plasma Sintering Process in Powder Metallurgy

Sintering unalloyed titanium in DC electrical abnormal glow discharge

Plasma sintering of unalloyed iron: a study of surface porosity

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