Synthesis and characterization of dense ultra-high temperature thermal protection materials produced by field activation through spark plasma sintering (SPS): I. Hafnium Diboride

Spark plasma sintering of Zr- and Hf-borides with decreasing amounts of MoSi2 as sintering aid

“…The considerable amount of HfO 2 (4 vol.%) accounts for oxygen contamination of the starting powder, as reported elsewhere. 19 Agglomerates of silicon carbide particles were observed in the microstruc- tures, see an example in Fig. 11d.…”

“…4,5 So far, few attempts have been made to densify these compounds by spark plasma sintering. HfB 2 and ZrB 2 with 15 vol.% MoSi 2 were densified to nearly full density at 1750 • C, whilst attempts to sinter as-received Hf-or Zr-borides powders led to very poor densification (about 70% of relative density) even at 2100-2200 • C. [19][20][21][22] In this contribution, a deeper investigation of the effect of spark plasma sintering on the densification of these borides is carried out. The aim is to obtain fine-grained and dense materials with as low as possible amount of sintering aid in order to minimize the deleterious effects of secondary phases.…”

Spark Plasma Sintering as a Useful Technique to the Nanostructuration of Piezo‐Ferroelectric Materials

“…[71] In the case of the refractory materials, as for example HfB 2 , the simultaneous synthesis and sintering produced dense ceramics (with 98% of the theoretical density) at lower pressure and temperature. [72] In order to explore the possibility of using SPS as a technique to can carry out a new sort of solid-state chemistry, the behaviour of the system M/V 2 O 5 (M ¼ Ag, Cu, Zn) during the SPS process has been investigated. The formation of different M x V 2 O 5 phases has been observed in a few minutes, even without a holding time at the final sintering conditions (Fig.…”

Consolidation via spark plasma sintering of HfB2/SiC and HfB2/HfC/SiC composite powders obtained by self-propagating high-temperature synthesis

“…the relatively shorter processing times and lower temperature levels, with respect to the corresponding HP values. For the same reasons, SPS was recently exploited for the fabrication of bulk ultra high-temperature ceramics [17,[21][22][23][24][25][26].…”