Ultrasound assisted combustion synthesis of TiC in Al–Ti–C system

Liu, Zhiwei; Rakita, Milan; Xu, Wilson; Wang, Xiaoming; Han, Qingyou

doi:10.1016/j.ultsonch.2015.04.025

Cited by 19 publications

(8 citation statements)

References 21 publications

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“…The formation of TiO 2 (Equation (1)) is easier than that of TiC (Equation (2)), evidenced by the higher enthalpy in Table 2, and the formation of TiO 2 releases a higher heat amount for subsequent combination of TiC, leading to the obviously enhanced characteristic peaks corresponding to TiC. Besides, the subsequent reduction reaction between CO (derived from the transformation of impurities in CB) and Ti left preferentially occurs, as in Equation (6), due to the higher Gibbs enthalpy (Equations (3)-(5)) not occurring (due to their positive ∆Gs), which is completely consistent with the literature [33,34]. But the oxidation of TiC takes place as Equation (8), due to the higher ∆H and ∆G than that of Equation (7) above 973 K, leading to the absence of TiC for S3.…”

Section: Discussionsupporting

confidence: 87%

Real-Time Measurement on the Heat Release Property of Titanium Blended with Different Carbon Allotropes, under Externally Constant Heat Flux

Wang

Zhao

2019

Metals

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Ti/C blended powder is commonly employed as an initiating combustion agent for preparing calcium aluminate; a dedicated test system is exploited for real-time examining of the heat release of Ti/C blended powder during combustion under atmosphere conditions with an externally constant heat flux of 973 K, which is comprised of cone calorimeter, thermal-gravimetry/differential scanning calorimetry, X-ray diffraction (XRD), scanning electron microscope/energy dispersive spectrometer, and a theoretical thermal calculation, with the aim of quantitatively illuminating its combustion mechanism in depth. Furthermore, a comparison of the heat release property of titanium powder blended with different carbon allotropes, including natural flaky graphite (FG), carbon black (CB), expandable graphite (EG), and vermicular graphite (VG) is preliminarily investigated, to clarify the effect of different carbon allotropes on the heat release property of Ti/C blended powder. It reveals that the oxidation reaction between Ti and O 2 initiates the subsequent combination of TiC through a thermal explosion reaction, using graphite (FG, VG, or EG) and Ti powder as the starting materials, respectively. Moreover, EG facilitates an accelerated (fire growth index of 0.42 kW·m −2 ·s −1 ) and enhanced peak heat release rate (pHRR) of 30.7 kW·m −2 at 73 s, while VG suppresses the heat release with the pHRR of 5.2 kW·m −2 at 64 s and fire growth index of 0.08 kW·m −2 ·s −1 , and FG favors the formation of TiC with a higher crystallinity from XRD. Additively, the prior NaOH-impregnation is favorable for the formation of TiC for Ti/CB blended powder, although the TiO 2 predominates final combustion production. It reveals the chemical evolution and mechanisms evolved in the formation of TiC during ignition.Metals 2019, 9, 981 2 of 16 contains expandable graphite (EG), vermicular graphite (VG), or expanded graphite after instantaneous expansion of EG, and natural flaky graphite (FG), which hold obviously different micro-structures and properties. Therefore, the various carbon sources affect the productions formed by SHS reaction [11]. It has been reported that the carbon nanotube and graphene as carbon sources impart enhanced tribological properties [12]; CB favors the formation of nano-metric TiC-carbon composite with a smaller particle size, as the most effective carbon allotrope for hindering the sintering of TiC under high temperature [13]. However, there is an interesting phenomenon-that the explosive reaction between graphite and titanium powder occurs under atmospheric pressure at 973 K with a transiently glaring flame, which inspired us to excavate its reaction mechanism, in order to explain the curious phenomenon.Consequently, the real-time measurement of heat release property involved in titanium blended with different carbon allotropes is preliminarily investigated, which is detected and recorded by cone calorimeter (CC) and thermal-gravimetry/differential scanning calorimetry (TG/DSC), respectively, using FG, CB, EG, and VG as different ...

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Section: Discussionsupporting

confidence: 87%

Real-Time Measurement on the Heat Release Property of Titanium Blended with Different Carbon Allotropes, under Externally Constant Heat Flux

Wang

Zhao

2019

Metals

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“…This is consistent with the XRD analysis, as shown in Figure 5. According to the thermodynamic analysis of the Al–Ti–C system [34], it is clear that the TiC phase was more thermodynamically stable than the Ti–Al phases due to its lower △G. Therefore, during the formation of the diffusion layer, the TiC phase will be excised in the diffusion layer when the Ti–Al phases are formed.…”

Section: Discussionmentioning

confidence: 99%

Effect of Diffusion Annealing Temperature on the Formation Process and Properties of a Carbon–Aluminum Composite Layer on Pure Titanium

et al. 2019

Materials

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A carbon–aluminum composite layer was prepared on the surface of pure titanium by double glow plasma carburizing, magnetron sputtering aluminizing, and vacuum-diffusional annealing treatment. The microstructure, phase composition, and properties of the composite layer obtained at different annealing temperatures were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and the ball-on-disc wear method. Results showed that the layer contained a mixture of TiAl3, Ti2Al5, and TiC phases at 650 °C for 6 h, which can significantly enhance the hardness and wear resistance of pure titanium. The layer exhibited a higher hardness of around 1231 HV0.1, a lower friction coefficient of 0.33, and lower wear volumes of 0.018 mm3 than those of the titanium substrate.

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“…However, there were some unreacted graphite particles in the final product, as shown in Figure 9c. Recently, Liu et al found that ultrasound is able to promote combustion synthesis reactions in the Al-Ti-C system to be more complete [81]. High-intensity ultrasound could accelerate the formation of a saturated solution of C atoms in the Al–Ti melt, and the nucleation and growth of TiC could also be promoted.…”

Section: The Synthesis and Characterization Of Three-dimensional Tmentioning

confidence: 99%

“…In previous studies, graphite particles of approximately 5 μm, 15 μm, 38 μm or even 48 μm were reported as used to fabricate TiC [30,75,80,86]. Becasuse graphite has a large size, it always becomes a residual phase in the reactant and has not been completely reacted with Ti, except for via some special measures [81]. Wang et al suggested that the residual graphite in the reactant was actually graphite flake agglomerations [87].…”

Section: The Synthesis and Characterization Of Three-dimensional Tmentioning

confidence: 99%

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

Dong

Qiu

et al. 2019

Nanomaterials

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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.

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Ultrasound assisted combustion synthesis of TiC in Al–Ti–C system

Cited by 19 publications

References 21 publications

Real-Time Measurement on the Heat Release Property of Titanium Blended with Different Carbon Allotropes, under Externally Constant Heat Flux

Real-Time Measurement on the Heat Release Property of Titanium Blended with Different Carbon Allotropes, under Externally Constant Heat Flux

Effect of Diffusion Annealing Temperature on the Formation Process and Properties of a Carbon–Aluminum Composite Layer on Pure Titanium

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

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