484
A. Calka et al. / Journal of Alloys and Compounds 467 (2009) 477–484
Although, the reactions occurring during EDAMM are poorly
Acknowledgements
understood, we may say that the first step in plasma processing
is the production of plasma by ionization. Primary ions of a car-
rier gas (Argon) are produced, which then transfer excitation
and ionization to powder particle surfaces, producing ions and
radicals – the reactant precursors. The plasma flow of gas ions,
free radicals and reactant ions bombard the powder surfaces with
high energy causing ion implantation. The interaction between
the particle surface and the arriving radicals leads to the nucle-
ation and growth of new phases by deep penetration of ions and
subsequent diffusion. A possible mechanism is shown in Fig. 14.
layer on the outside of some particles may be melted. These can
form agglomerates under the influence of electrostatic forces,
and these agglomerates are seen in the SEM micrographs (e.g.,
Fig. 6). The localized heating also results in the crystallite size
of the reaction products being much larger than those formed
by conventional milling. This is evidenced by the XRD patterns
after EDAMM that show sharp peaks indicative of larger crystal
sizes, as compared to the diffuse peaks observed by Balaz et al.
after conventional milling [3].
This investigation was supported by funding from the
Australian Research Council (Grant Nos. A00103022 and
DP0451907) and Slovak Science and Technology Assistance
Agency (Grant No. LPP-0196-06).
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5. Conclusions
PbS and Sb2S3 have been successfully reduced with both Fe
and Mg using the novel synthesis technique of electrical dis-
charge assisted ball milling. This is the first ever report of the
reduction of PbS and Sb2S3 using Mg as the reducing agent. In
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