Catalyst‐free in situ synthesis of ZrC nanowires with excellent thermal stability

Abstract

No catalyst‐assisted zirconium carbide nanowires (ZrCNWs) were successfully synthesized by thermal evaporation and in situ reaction using carbon nanotubes (CNTs) and ZrCl4 as carbon and zirconium sources. Vapor‐Solid (VS) mechanism was proposed to explain the growth process of ZrCNWs. The ZrCNWs prepared at 1400°C have a single crystal structure with the diameters of 130‐290 nm. The axial growth direction of ZrCNWs is [111] and the yield is 76.5 wt%. After heat treatment at 1700°C, 2100°C, and 2450°C, the diameter of ZrCNWs increased and their aspect ratio decreased. By simulating the thermal stress of a single ZrCNW, it is speculated that the coarsening and fracture of ZrCNWs are caused by the overall slip of the atomic layers and the stress concentration at the dislocations.

Recent Progress in 1D Nanostructures Reinforced Carbon/Carbon Composites

“…CNTs Templated Thermal Evaporation: Thermal evaporation method using CNTs as templates was usually carried out to synthesize 1D ceramic nanomaterials, such as SiCNWs, HfCNWs, and ZrCNWs [52,80,81] (Figure 4g). Typically, CNTs are first deposited on the surface of carbon fibers through EPD method, which were served as templates and carbon source.…”

“…[228] Moreover, ZrCNWs could be fabricated using the CVD method, CNTs templated thermal evaporation method, microwave hydrothermal & carbothermal reduction, and pyrolysis of polymeric precursor method. [81,[226][227][228][229][230] Chiu et al prepared ZrCNWs with different surface states on a graphite substrate by catalyst-assisted CVD using ZrCl 4 and CH 4 as reagents. [226,227] The results show that ZrCNWs possess the advantages of low work function, low turn-on voltage, and high current density, demonstrating ZrCNWs have a great potential in the application of field emission.…”

“…Yan et al have successfully synthesized ZrCNWs using catalyst-free CNTs templated thermal evaporation method and investigated their high-temperature thermal stability (Figure 22a,b). [81] Further, V-S mechanism was proposed to explain the growth of ZrCNWs (Figure 22c). Due to the slip of atomic layer along a certain crystal plane and the stress concentration at the dislocations, ZrCNWs are apparently coarsened at 2100 °C and break into short whiskers at 2450 °C, showing ZrCNWs possess the better thermal stability at ultrahigh temperature than SiCNWs.…”

“…Benefiting from the synergistic effects of SiCNWs and Si 3 N 4 NBs, SiCNWs-Si 3 N 4 NBs-C/C composites Reproduced with permission. [81] Copyright 2020, American Ceramic Society. d) Schematic diagram of ZrCNWs prepared by pyrolysis of polymeric precursor method.…”

“…Figure 22. a) Schematic diagram, b) SEM image, and c) growth mechanism of ZrCNWs prepared by CNTs templated thermal evaporation method.Reproduced with permission [81]. Copyright 2020, American Ceramic Society.…”