Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

Author Brunatto, S.f. Autor UNIFESP Google Scholar
Kühn, I. Google Scholar
Muzart, J.l.r. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade Federal de Santa Catarina Department of Mechanical Engineering
Abstract The present work reports an investigation of the influence of the radial spacing between cathodes on the iron sintering process by hollow cathode electrical discharge, with surface enrichment of the alloying elements Cr and Ni. Pressed cylindrical samples of 9.5 mm diameter and density of 7.0 ± 0.1 g/cm³ were prepared by compaction of Ancorsteel 1000C iron powder. These samples, constituting the central cathode, were positioned concentrically in the interior of an external cathode machined from a tube of stainless steel AISI 310 (containing: 25% Cr, 16% Ni, 1.5% Mn, 1.5% Si, 0.03% C and the remainder Fe). Sintering was done at 1150 °C, for 120 min, utilizing radial spacings between the central and hollow cathodes of 3, 6 and 9 mm and a gas mixture of 80% Ar and 20% H2, with a flow rate of 5 cm³/s at a pressure of 3 Torr. The electric discharge was generated using a pulsed voltage power source, with a period of 200 mus. The radial spacing had only a slight influence on the quantity of atoms of alloying elements deposited and diffused on the surface of the sample. Analysis with a microprobe showed the presence of chrome (up to 4.0%) and nickel (up to 3.0%, in at. %) at the surface of the samples. This surface enrichment can be attributed to the mechanism of sputtering of the metallic atoms present in the external cathode, with the deposition of these elements on the sample surface and consequent diffusion within the sample.
Keywords hollow cathode discharge
plasma sintering
sintered iron
surface deposition of alloying elements
Language English
Date 2001-10-01
Published in Materials Research. ABM, ABC, ABPol, v. 4, n. 4, p. 245-250, 2001.
ISSN 1516-1439 (Sherpa/Romeo)
Publisher ABM, ABC, ABPol
Extent 245-250
Origin http://dx.doi.org/10.1590/S1516-14392001000400005
Access rights Open access Open Access
Type Article
SciELO ID S1516-14392001000400005 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/1249

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