Oil Removal from Sintered Iron Using Plasma DC Discharge

Santos, M.A.; Silva, H.R.T.; Muzart, J.L.R.; Maliska, A.M.

doi:10.4028/www.scientific.net/msf.416-418.449

Cited by 3 publications

(2 citation statements)

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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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Section: Introductionmentioning

confidence: 99%

Plasma sintering of unalloyed iron: a study of surface porosity

et al. 2004

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“…However, considering that the binder degradation is performed by thermal mechanism, the process is relatively slow, lasting more than 10 h. In addition, hydrocarbon molecules deposit on the support of the pieces and on the walls of the vacuum furnace requiring periodic cleaning of the equipment. The application of glow discharge on powder metallurgy processing is mainly used for cleaning 7 , delubing 8 and sintering [9][10][11][12][13][14][15] . Recently, a novel application to perform the debinding of components produced by injection molding was briefly published 16,17 , and is discussed in more details in this paper.…”

Section: Introductionmentioning

confidence: 99%

Plasma debinding and pre-sintering of injected parts

et al. 2004

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Results of polypropylene removal in injected metallic parts by using plasma technology are presented. The samples were injected with 55.18% Vol. of unalloyed iron powder, 23.57% Vol. of paraffin and 21.25% Vol. of polypropylene. The paraffin was previously removed in hexane bath, followed by a treatment in abnormal glow discharge of argon and hydrogen for the removal of the polypropylene. The electric discharge was generated in two configurations: a confined anode-cathode with the samples placed on the anode and a confined grid (anode)-cathode system with the sample placed on a holder at floating potential inside the grid. In the first geometry, electrons bombarded the sample surface, while in the second, they are collected by the grid. The samples were characterized by mass loss measurements and scanning electron microscopy. The results showed that the hydrogen discharge was more efficient for both configurations, which is attributed to the high reactivity of hydrogen atoms produced in the discharge. In addition, when plasma debinding was performed at 400 ºC for 10 min, by using the confined anode-cathode configuration, the polypropylene removal was total, while in the confined grid (anode)-cathode geometry the removal was approximately 32%. The higher polypropylene removing observed in the anode-cathode configuration is attributed to electron bombardment of the surface of the sample

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DC Plasma Technology Applied to Powder Metallurgy: an Overview

Klein¹,

Cardoso²,

Pavanati³

et al. 2013

Plasma Sci. Technol.

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DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy (PM) and powder injection molding (PIM) parts production, are lowpressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

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Oil Removal from Sintered Iron Using Plasma DC Discharge

Cited by 3 publications

References 0 publications

Plasma sintering of unalloyed iron: a study of surface porosity

Plasma sintering of unalloyed iron: a study of surface porosity

Plasma debinding and pre-sintering of injected parts

DC Plasma Technology Applied to Powder Metallurgy: an Overview

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