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Self-consolidation mechanism of nanostructured Ti5Si3 compact induced by electrical discharge.

Lee WH, Cheon YW, Jo YH, Seong JG, Jo YJ, Kim YH, Noh MS, Jeong HG, Van Tyne CJ, Chang SY - ScientificWorldJournal (2015)

Bottom Line: A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge.Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact.Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea.

ABSTRACT
Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a) a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b) melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c) rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

No MeSH data available.


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XPS narrow scan spectra of the (a) Ti 2p and (b) Si 2p region of MAed Ti5Si3 powder before and after light Ar+ etching for 5 minutes.
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fig3: XPS narrow scan spectra of the (a) Ti 2p and (b) Si 2p region of MAed Ti5Si3 powder before and after light Ar+ etching for 5 minutes.

Mentions: To investigate the surface chemical states of MAed Ti5Si3 powder, XPS was carried out. Figure 3(a) shows narrow scan spectra of the Ti 2p region before and after light Ar+ etching for 5 minutes. For the MAed Ti5Si3 powder before etching, a Ti 2p3/2 peak at 459.2 eV is shown, with 5.8 eV splitting between the Ti 2p1/2 and Ti 2p3/2 peaks. The Ti 2p3/2 peak at 459.2 eV corresponds to TiOx, implying that the surface of MAed Ti5Si3 powder is primarily in the form of titanium oxide [16, 17]. However, after etching the MAed Ti5Si3 powder, the Ti 2p3/2 peak shifted to lower binding energy, 453.4 eV, which indicates the presence of titanium silicide [18]. It can thus be known that the MAed Ti5Si3 powder was lightly oxidized. Figure 3(b) shows narrow scan spectra of the Si 2p region before and after light Ar+ etching for 5 minutes. For the MAed Ti5Si3 powder before etching, a Si 2p peak at 102.5 eV corresponds to SiOx [18]. After etching the MAed Ti5Si3 powder, the Si 2p peak shifted to lower binding energy, 98.2 eV, which indicates the presence of titanium silicide [18]. This result also supports that the MAed Ti5Si3 powder was lightly oxidized.


Self-consolidation mechanism of nanostructured Ti5Si3 compact induced by electrical discharge.

Lee WH, Cheon YW, Jo YH, Seong JG, Jo YJ, Kim YH, Noh MS, Jeong HG, Van Tyne CJ, Chang SY - ScientificWorldJournal (2015)

XPS narrow scan spectra of the (a) Ti 2p and (b) Si 2p region of MAed Ti5Si3 powder before and after light Ar+ etching for 5 minutes.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4389978&req=5

fig3: XPS narrow scan spectra of the (a) Ti 2p and (b) Si 2p region of MAed Ti5Si3 powder before and after light Ar+ etching for 5 minutes.
Mentions: To investigate the surface chemical states of MAed Ti5Si3 powder, XPS was carried out. Figure 3(a) shows narrow scan spectra of the Ti 2p region before and after light Ar+ etching for 5 minutes. For the MAed Ti5Si3 powder before etching, a Ti 2p3/2 peak at 459.2 eV is shown, with 5.8 eV splitting between the Ti 2p1/2 and Ti 2p3/2 peaks. The Ti 2p3/2 peak at 459.2 eV corresponds to TiOx, implying that the surface of MAed Ti5Si3 powder is primarily in the form of titanium oxide [16, 17]. However, after etching the MAed Ti5Si3 powder, the Ti 2p3/2 peak shifted to lower binding energy, 453.4 eV, which indicates the presence of titanium silicide [18]. It can thus be known that the MAed Ti5Si3 powder was lightly oxidized. Figure 3(b) shows narrow scan spectra of the Si 2p region before and after light Ar+ etching for 5 minutes. For the MAed Ti5Si3 powder before etching, a Si 2p peak at 102.5 eV corresponds to SiOx [18]. After etching the MAed Ti5Si3 powder, the Si 2p peak shifted to lower binding energy, 98.2 eV, which indicates the presence of titanium silicide [18]. This result also supports that the MAed Ti5Si3 powder was lightly oxidized.

Bottom Line: A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge.Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact.Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea.

ABSTRACT
Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a) a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b) melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c) rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

No MeSH data available.


Related in: MedlinePlus