Combustion synthesis of SiC-based ceramics reinforced by discrete carbon fibers with in situ grown SiC nanowires

Vorotilo, S.; Potanin, A. Yu.; Логинов, П.А.; Shvindina, N.V.; Левашов, Е. А.

doi:10.1016/j.ceramint.2019.12.005

Cited by 17 publications

(12 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of TaSiC-nw composition, heterogeneous composite particles were surrounded by 5-10 μm long SiC nanowires. The mechanism of nanowire growth in this system was reported earlier [14,56].…”

Section: Characterization Of the Ceramic Powderssupporting

confidence: 61%

“…Previous investigations [14,56] have demonstrated that the highest quantity and quality of nanowires produced by the combustion of Ta-Si-C-C 2 F 4 mixture was achieved if the combustion temperature of the mixtures was close to 1700 K. The overall temperature window (~200 K) was outlined, in which the growth of SiC nanowires was possible. The combustion temperature was controlled by adjusting the diameter of green pellets and the C:C 2 F 4 ratio in the green mixture.…”

Section: Preparation Of Composite Powdersmentioning

confidence: 96%

“…In this work, the following two heterophase experimental models in the Ta-Si-C system were prepared using mechanically activated combustion synthesis: TaSi 2 -TaC-SiC ceramic powders [54,55], designated TaSiC, and discretely-reinforced TaSi 2 -TaC-SiC-SiC nanowire composition [14,56], designated TaSiC-nw.…”

Section: Preparation Of Composite Powdersmentioning

confidence: 99%

“…Currently, there is very limited available data on the topics of sintering mechanisms of heterophase non-oxide nanoceramics, including SiC nanowire-reinforced compositions. The Ta-Si-C system is particularly interesting in this regard because it features a reversible phase reaction resulting in the formation of silicon-based melt [14]. Sintering techniques involving a transient liquid phase are widely used in ceramic manufacturing [45]; therefore, the investigation of the influence of SiC nanowires on the melt formation and overall sintering mechanisms in heterogeneous non-oxide compositions is both scientifically novel and practically applicable.…”

mentioning

confidence: 99%

“…In this work, two experimental models in the Ta-Si-C system were used for the investigation of the effect of SiC nanowires on the sintering behavior of heterogeneous ceramics, i.e., nanostructured SiC-TaSi 2 ceramic composite and discretely-reinforced ceramic SiC-TaSi 2 -SiC nanowire . Experimental samples with uniform distribution of SiC nanowires were prepared using the recently developed (Ta + C 2 F 4 )-activated combustion route [14]. A temperature interval of 1300-1500 • C temperature was used for the study on the influence of in situ SiC nanowires on the kinetics and structural formation mechanisms in the case of solid sintering and sintering with the transient liquid phase.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Effect of In Situ Grown SiC Nanowires on the Pressureless Sintering of Heterophase Ceramics TaSi2-TaC-SiC

et al. 2020

View full text Add to dashboard Cite

To ascertain the influence of SiC nanowires on sintering kinetics of heterophase ceramics, two composite powders (TaSi2-TaC-SiC and TaSi2-TaC-SiC-SiCnanowire) are fabricated by mechanically activated combustion synthesis of Ta-Si-C and Ta-Si-C-(C2F4) reactive mixtures. Remarkable compressibility is achieved for the TaSi2-TaC-SiC-SiCnanowire composition (green density up to 84% as compared with 45.2% achieved for TaSi2-SiC-TaC) which is attributed to the lubricating effect of residual adsorbed fluorinated carbon (most likely C4F8). The outcomes of pressureless sintering of TaSi2-TaC-SiC and TaSi2-TaC-SiC-SiCnanowire compositions are vastly different; the former experiences no significant densification or grain growth and does not attain structural integrity, whereas the latter achieves relative density up to 93% and hardness up to 11 GPa. The SiC nanowires are not retained in consolidated ceramics, but instead, act as a sintering aid and promote densification and grain growth. Sintering mechanisms of TaSi2-TaC-SiC and TaSi2-TaC-SiC-SiCnanowire powders are analyzed using thermodynamic and ab initio grand potential calculations, as well as the analysis of grain size versus relative density relations. In the case of solid-state sintering, the densification and grain growth in heterophase non-oxide ceramics are governed by the same mechanisms as previously investigated single-phase oxides. The presence of SiC nanowires enhances grain-boundary related diffusion processes due to the high specific surface and aspect ratio of the nanowires. At 1500 °C, where the formation of the transient Si-based liquid phase is thermodynamically viable, only the SiC nanowire-containing composition demonstrated the intense grain coarsening and densification associated with liquid-assisted sintering. This effect can be attributed both to the presence of SiC nanowires and purification of residual oxide impurities due to C2F4-activated combustion synthesis employed for the in situ formation of SiC nanowires.

show abstract

Section: Characterization Of the Ceramic Powderssupporting

confidence: 61%

Section: Preparation Of Composite Powdersmentioning

confidence: 96%