The Synthesis, Structure, Morphology Characterizations and Evolution Mechanisms of Nanosized Titanium Carbides and Their Further Applications

Abstract

It is widely known that the special performances and extensive applications of the nanoscale materials are determined by their as-synthesized structures, especially their growth sizes and morphologies. Hereinto, titanium carbides, which show brilliant comprehensive properties, have attracted considerable attention from researchers. How to give full play to their potentials in the light-weight manufacture, microwave absorption, electromagnetic protection, energy conversion and catalyst areas has been widely studied. In this summarized article, the synthesis methods and mechanisms, corresponding growth morphologies of titanium carbides and their further applications were briefly reviewed and analyzed according to their different morphological dimensions, including one-dimensional nanostructures, two-dimensional nanosheets and three-dimensional nanoparticles. It is believed that through the investigation of the crystal structures, synthesis methods, growth mechanisms, and morphology characterizations of those titanium carbides, new lights could be shed on the regulation and control of the ceramic phase specific morphologies to meet with their excellent properties and applications. In addition, the corresponding development prospects and challenges of titanium carbides with various growth morphologies were also summarized.

Keywords: crystal growth mechanism; excellent performances; morphology evolution manipulation; nanostructures; titanium carbides.

Figure 1

Various morphologies of titanium carbides with different dimensionalities reported recently and some of their applications. One dimensional: With permission from Reference [7], copyright (2013) Elsevier. With permission from Reference [8], copyright (2011) American Chemical Society. With permission from Reference [10], copyright (2015) Elsevier. With permission from Reference [22], copyright (2018) Elsevier. With permission from Reference [23], copyright (2010) Royal Society of Chemistry; Two dimensional: With permission from Reference [3], copyright (2018) Royal Society of Chemistry. With permission from Reference [12], copyright (2012) American Chemical Society. With permission from Reference [24], copyright (2019) American Chemical Society. With permission from Reference [25], copyright (2017) Royal Society of Chemistry; Three dimensional: With permission from Reference [13], copyright (2009) American Chemical Society. With permission from Reference [15], copyright (2012) Royal Society of Chemistry. With permission from Reference [16], copyright (2008) Elsevier. With permission from Reference [26], copyright (2017) the authors. With permission from Reference [17], copyright (2017) Royal Society of Chemistry. With permission from Reference [18], copyright (2011) Elsevier. With permission from Reference [27], copyright (2004) Elsevier.

Figure 2

Various applications of titanium carbides nanostructures. (a) Electromagnetic shielding. With permission from Reference [28], copyright (2018) American Chemical Society. (b) Microwave absorption. With permission from Reference [3], copyright (2018) Royal Society of Chemistry. (c) Energy transformation. With permission from Reference [25], copyright (2010) Royal Society of Chemistry (d) Microstructure refinement. With permission from Reference [29], copyright (2018) Elsevier; (e) Strength&ductility enhancement. With permission from Reference [2], copyright (2018) Elsevier.

Figure 3

(a) The crystal structure of TiC; (b) The TiC crystal structure view along [100]; (c) The TiC crystal structure view along [111].

Figure 4

The structures schematic diagrams of TiC_x phases with different stoichiometric ratio (as calculated by a 16-atom supercell). Z shows the different planes in the TiC_x crystal, and the four planes from top to bottom are marked as 0, 0.25, 0.5 and 0.75, respectively.

Figure 5

The surface energy ratio limits for observing the (a) critical nucleus and (b) growth shapes in the cuboctahedral morphologies, (c) The calculated model of octahedron and cube.

Figure 6

(a) The cross-sectional schematics of the TiC nanorods formation mechanism and (b) a high-magnification SEM image of nanorod arrays along the cotton fiber radial direction. The inset of b shows the catalyst Ni particles on the tips of the nanorods, with permission from Reference [8], copyright (2011) American Chemical Society; (c) Synthetic approach for TiC nanowires-ZrSiO₄ and VSL growth of TiC nanowire and (d) the as-prepared TiC-ZrSiO₄ composites. The high-magnification image of TiC nanowires is shown in the inset with permission from Reference [7], copyright (2014) Elsevier. (e) A simple mode for the VS growth of TiC whiskers on Ti₃O₅ particle. The left image is the nucleation of TiC on a Ti₃O₅ particle. The right image shows faceted TiC whiskers growing along the [100] direction, with the TiC epitaxially growing into a branch structure on the lateral surface of a TiC whisker shows in the inset (f) The cross section of TiC whiskers and SEM images of the TiC whiskers after separation with permission from Reference [10], copyright (2015) Elsevier.

Figure 7

(a) The atomic structure of the Ti₃AlC₂ MAX phase and a high-angle annular dark-field (HAADF) image of multilayer Ti₃C₂T_x (here the image only shows the inheritance of Ti₃C₂T_x from the parent Ti₃AlC₂, so we use this image to represent the MAX phases arrangement, and the inherited Ti₃C₂T_x can be seen as a Ti(s)-C-Ti(c)-C-Ti(s) arrangement). The final Ti₃C₂T_x monolayers in (b) show that on both sides of the Ti₃C₂ layer, the functional groups (-O and/or -F) atoms favor staying on top of the Ti(c) atoms rather than at the topmost sites of the C atoms, with permission from Reference [64], Copyright (2015) American Chemical Society. (c) The schematic diagram of the etching treatment and exfoliation process to remove the ‘A’ layer from the MAX phase to obtain MXenes. (d–f) The actual morphology evolutions from the MAX phase to MXenes, and to nanosheets by exfoliation, with permission from Reference [12], copyright (2012) American Chemical Society. With permission from Reference [62], copyright (2015) Elsevier. (g) The X-Ray Diffraction (XRD) analysis of Ti₃AlC₂ before and after HF treatment for 2 h, 10 h, and 20 h. (h–k) are the corresponding SEM images of the as-prepared MXenes. With permission from Reference [66], copyright (2016) Elsevier.

Figure 8

(a) The optimized geometries of the free-standing tetr-TiC sheet and the comparison of different titanium carbide materials, with permission from Reference [5], copyright (2018) American Chemical Society. (b) The morphological evolution of Ti₃C₂T_x (T = -O,-OH or -F) after LiF/HCl etching of Ti₃AlC₂ and centrifuging for different times, with permission from Reference [24], copyright (2019) American Chemical Society. (c) The synthesis mechanism of Ti₃C₂T_x MXenes/nanocarbon-sphere hybrids. First, the Al layer is removed from the corresponding MAX phase by HF. Second, part of the carbon atoms are migrated to the surface of the Ti₃C₂T_x MXenes. This process can be controlled by using different HF treatment times, and microwave absorption effects are also exhibited. Used with permission from Reference [3], copyright (2018) The Royal Society of Chemistry.

Figure 9

Changes in (a) reaction enthalpy, ∆H and (b) Gibbs free energy, ∆G in Ti-Al-C system; (c) Proposed mechanism of ignition and reaction of the Ti-Al-C system according to Lee et al.

Figure 10

(a) A packing scheme of octahedral TiC in the edge-shared manner and layer-by-layer mechanism. (b) SEM images of TiC particles synthesized via SHS: (b1) a high magnification and (b2) an edge-sharing of octahedral TiC, with permission from Reference [14], copyright (2009) Elsevier; (c) Schematic illustration of TiC_x growth morphologies. With permission from Reference [86], copyright (2012) American Chemical Society; (d) FESEM (Field emission scanning electron microscope) images of TiC_x particles, with permission from Reference [13], copyright (2012) American Chemical Society.

Figure 11

The nanosized TiC_p extracted from the as-synthesized TiC_p/Al-Cu-Mg-Si nanocomposites produced using different carbon sources: (a) carbon black, (b) mixed carbon source (50 wt.% carbon nanotubes (CNTs) + 50 wt.% carbon black), and (c) CNTs. The TEM images of the 10 vol.% TiC_p/Al-Cu-Mg-Si nanocomposite (fabricated by mixed carbon source) after tensile testing at 298 K: (d) the distribution of TiC_p, (e) the morphology and interface of the observed TiC_p, and (f) the corresponding TiC_p/α-Al interface bonding. With permission from Reference [92], copyright (2019) Elsevier; (g) The XRD phase analysis and SEM micrographs of (h) the Al-30 vol.% (TiC_n-Al₃Ti_m) master alloy, (i) the TEM image of nano-TiC particles in the master alloy, (j) nano-TiC particle selected area electron diffraction (SAED) pattern, (k) A FESEM micrograph of the extracted TiC particles morphology and (f) TiC particles size distribution statistical histogram; With permission from Reference [19], copyright (2019) Elsevier.

Figure 12

(a) The theoretical and actual stoichiometric ratios and the corresponding extracted TiC_x lattice parameters; (b) The lattice parameters and corresponding estimated stoichiometric ratios of TiC_x in this case compared with previously reported experimentally determined data; (c) The TiC_x nanoparticles morphology evolution manipulating mechanism by the stoichiometric ratios in the Al melt. With permission from Reference [101], copyright (2019) Elsevier.

Figure 13

(a) TiC morphology evolution model schematic illustration in Al-Ti-C (Route I) and Al-Ni-Ti-C systems (Route II). (100) and (111) faces are shown in green and purple, respectively. (b) The possible morphology of TiC_x in the Al-Ti-C melt. (c) The morphology of TiC_x under the influence of Ni, with permission from Reference [15], copyright (2012) Royal Society of Chemistry. (d) Hexagonal TiC platelet growth schematic illustration. (e) TiC platelets (e1) formed on the surface of the Ti/Si/TiC/Al_0.2 sample (obtained after 1500 °C sintering for 10 min in Ar atmosphere) and (e2) on the surface of Ti/Si/Al_0.2 (obtained after 1450 °C sintering for 10 min), with permission from Reference [16], copyright (2008) Elsevier.

Figure 14

(a) the schematic diagram of the formation and separation of TiC in Cu-Ti melts. Some TiC that fails to break away from the graphite will form (b) TiC agglomerations or (c) partly integrate into larger plate-like morphologies. (d) Spherical and (e) polyhedron-like TiC particles in melts. With permission from Reference [115], copyright (2017) Elsevier.; (f–i) The extracted TiC particles synthesized by Cu-Ti-C system with different Cu content (from 60 vol.% to 90 vol.%).

Figure 15

(a) Scheme of the growth process of TiC terraces in Fe-Ti-C system. (b) The morphology of TiC terraces synthesized in the Fe-Ti-C system. With permission from Reference [18], copyright (2011) Elsevier; (c,d) The TiC nanocrystal clusters that grow on the surface of Ti particles, with permission from Reference [120], copyright (2015) Elsevier; (e) Based on the TiC particles complete melting mechanism, the integrated dendrite development schematic diagram. (f,g) The actual TiC particles melting and dendrite development. With permission from Reference [17], copyright (2017) Royal Society of Chemistry; (h) The microstructure of 20 vol.%TiC/Ni composites. The large cubic TiC is the primary phase, while the fine fibrous shape is the eutectic phase. With permission from Reference [122], copyright (2010) Elsevier.

Figure 16

(a) Principle components of the arc discharge vessel and the various nanoparticle morphologies produced with different carbon concentrations. (b–e) TEM images of cube- and cuboctahedron-shaped nanoparticles synthesized with (b) 5%, (c) 30%, (d) 60% and (e) 100% methane. (f) Bar graph displaying the abundances of different morphologies synthesized with varying methane concentrations. It can be seen that at low methane concentrations, cubes were dominant, while at high methane concentrations, cuboctahedrons were dominant. With permission from Reference [41], copyright (2010) American Chemical Society; (g) TEM images of the TiC nanocubes and (h) the magnified detail of a cubic core-shell structure, with permission from Reference [125], copyright Elsevier, 2011; (i) TiC hollow spheres prepared at 400 °C. With permission from Reference [27], copyright Elsevier, 2004.