Dense nanostructured materials obtained by spark plasma sintering and field activated pressure assisted synthesis starting from mechanically activated powder mixtures

Abstract

The preparation of highly dense bulk materials with a grain size in the range of a few to a few hundreds nanometers is currently the objective of numerous studies. In our research we have achieved a measure of success in this regard by using the methods of mechanically-activated, field-activated, pressure-assisted synthesis, MAFAPAS, which has been patented, and mechanically-activated spark plasma sintering, MASPS. Both methods, which consist of the combination of a mechanical activation step followed by a consolidation step under the simultaneous influence of an electric field and mechanical pressure, have led to the formation of dense nanostructured ceramics, intermetallics, and composites, such as, MoSi2 FeAl, NbAl3, and TiN-TiB2. In this report, both one-step synthesis-consolidation and sintering of different nanostructured materials by SPS and FAPAS were investigated.

Oxidation resistance of SHS Fe–Al–Si alloys at 800 °C in air

“…Powders can be pre-activated by high energy millingemechanical alloying [21]. The energy for the activation of chemical reactions during reactive sintering is supplied by heating in vacuum or protective-atmosphere furnace [18,19] or by electric discharge [22,23]. When intermetallic phases are produced by this process, initial components can be metallic or alloy powders or other suitable precursors (compounds) [18,19].…”

Shape Memory NiTi and NiTiCu Alloys Obtained by Spark Plasma Sintering Process

“…Success in forming dense bulk nanostructures stems from the use of two forms of activation sequentially: mechanical alloying (MA) by high-energy ball milling and field activation by the use of high-density currents [6] The SPS process that relies on field activation is a newly developed synthesis and sintering process in which rapid powders densification can be obtained [7]. It is claimed that uses microscopic electric discharges between the particles under pressure [8].…”

Synthesis and consolidation of TiN/TiB2 ceramic composites via reactive spark plasma sintering

“…Moreover, the possibility of high exothermic reactions initiation in self-propagating high-temperature synthesis (SHS) mode by means of SPS technology [13] is also an advantage of this method. Numerous experimental investigations [1,6,[14][15][16] point to the ability of SPS to consolidate highly dense powder products with the potential of grain size retention. The latter ability is of significance for the consolidation of nanocomposites where the grain growth is one of the major problems.…”