Densification and preservation of ceramic nanocrystalline character by spark plasma sintering

Abstract

Spark plasma sintering is a hot pressing technique where rapid heating by dc electric pulses is used simultaneously with applied pressure. Thus, spark plasma sintering is highly suitable for rapid densification of ceramic nanoparticles and preservation of the final nanostructure. A considerable portion of the shrinkage during densification of the green compact of nanoparticles in the first and intermediate stages of sintering occurs during heating by particle rearrangement by sliding and rotation. Further densification to the final stage of sintering takes place by either plastic yield or diffusional processes. Full densification in the final stage of sintering is associated with diffusional processes only. Nanoparticle sliding and rotation during heating may also lead to grain coalescence, with much faster kinetics than normal grain growth at higher temperatures. Based on existing models for particle rearrangement and sliding, the contributions of these processes in conjunction with nanoparticle properties and process parameters were highlighted.

Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics

“…While pressure increase is efficient to achieve dense and nanosized structure [41], the decrease of temperature and holding time is noxious to get high final density: a compromise between densification and chemical stability has thus to be found. Further improvement on the sample homogeneity is restrained by the mechanical behavior of the graphite mold which cannot withstand more than 100 MPa for such temperatures.…”

Relationship between mechanical properties and microstructure of yttria stabilized zirconia ceramics densified by spark plasma sintering

“…This process, which belongs to the electric current assisted sintering technologies, allows to rapidly produce ceramic materials with high performances since nanosized grains are preserved in the microstructure [11][12][13][14][15][16]. Dudina et al in their last review on porous materials fabricated by SPS underline that there is no article related to the consolidation of porous YSZ and their mechanical properties [17].…”

Spark Plasma Sintering and Characterization of Graphene Platelet/Ceramic Composites

“…[22] However, abnormal grain growth and pore coarsening are likely to happen in this stage, resulting in degradation of the mechanical properties of the ceramics. At this stage, isolated pores are normally formed at grain boundaries and triple junctions.…”