Simultaneous synthesis and densification of WSi2 and WSi2-20vol.%Nb composite by field-activated and pressure-assisted combustion

Abstract

A method to simultaneously synthesize and consolidate the silicide WSi: and the composite WSi2-20 vol.%Nb from W, Si, and Nb powders was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. The fmat density of the products increased nearly linearly with the applied pressure. Highly dense WSi2 and WSi:-20 vol.%Nb with relative densities of up to 97% were produced under the simultaneous application of a 60 MPa pressure and a 3000A current on the reactant powders. The percentages of the total shrinkage occurring before and during the synthesis reaction were 17 and 83% for the WSi2, and 22 and 78% for the WSi:-20 vol.% Nb. The respective Vickers microhardness values for these materials were 8.2 and 5.8 GPa. From indentation crack measurements, the fracture toughness values for WSi2 and WSi2-20 vol.%Nb were calculated to be 3.2 and 9.1 MPa m ~, respectively.

Properties and consolidation of nanocrystalline 3Cu–Al2O3 composite by rapid sintering

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One step synthesis and densification of nanocrystalline TaSi2–Si3N4 composite from mechanically activated powders by high-frequency induction-heated combustion

“…However, the method of field-activated and pressure-assisted combustion synthesis has been successfully employed to synthesize and densify materials from the elements in one step in a relatively short period of time. This method has been used to synthesize a variety of ceramics and composites, including MoSi 2 -ZrO 2 , Ti 5 Si 3 and its composites, WSi 2 and its composites, and WC-Co hard materials [20][21][22][23][24][25]. These materials, which are generally characterized by low adiabatic combustion temperature, cannot be synthesized directly by the self-propagating high-temperature synthesis (SHS) method.…”

Simultaneous synthesis and consolidation process of ultra-fine WSi2–SiC and its mechanical properties

“…This method has been used to synthesize a variety of ceramics and composites, including MoSi 2 -ZrO 2 , Ti 5 Si 3 and its composites, WSi 2 and its composites, and WC-Co hard materials [12][13][14][15][16][17]. These materials that are generally characterized by low adiabatic combustion temperature cannot be synthesized directly by the self-propagating high-temperature synthesis (SHS) method.…”