Early stages of phase formation before the ignition peak during mechanically induced self-propagating reactions (MSRs) of titanium and graphite

Oghenevweta, J.E.; Wexler, David; Całka, A.

doi:10.1016/j.scriptamat.2016.05.028

Cited by 16 publications

(22 citation statements)

References 46 publications

(129 reference statements)

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“…In our previous work involving controlled ball milling of Ti with C (graphite) [31] and Ti with amorphous boron (B) [32], significant new insights were obtained, which parallels the previous understanding on the formation mechanism of MSR synthesis route. Apparently, these systems (Ti-C and Ti-B) represent metalmetalloid compositional mixtures, where the formation mechanism may likely differ from metal to gas system (Ti-N).…”

Section: Introductionsupporting

confidence: 64%

“…As shown in Fig. 1a, the sudden temperature increment is relatively very small, which is not consistent with higher temperature increment earlier detected by Chin et al [2,3] during milling of Ti and N, and also compared with the ball milling of Ti with C [31], and Ti with B powders [32], where the sudden temperature spike rises to about 25-30 o C above the based temperature. Moreover, the typical change in the sound of the balls motion was not detected here, probably suggesting a much slower transformation of the products.…”

Section: Materials and Experimental Procedurescontrasting

confidence: 53%

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Understanding reaction sequences and mechanisms during synthesis of nanocrystalline Ti2N and TiN via magnetically controlled ball milling of Ti in nitrogen

2017

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Mechanically induced reactive synthesis of TiN via magnetically controlled ball milling of titanium under nitrogen gas was investigated using X-ray diffraction, advanced electron microscopy and Raman spectroscopy. Ball milling of titanium powder with nitrogen gas was performed in Uni-Ball-Mill, with external temperature of the vial and initial pressures of the nitrogen gas monitored, while the milled samples were taken out periodically, both before and after detection of an exothermic ignition point. Before ignition, nitrogen-enriched Ti, small proportions of TiN and very minor amounts of Ti 2 N are formed, in addition to the heavily deformed Ti. Raman spectroscopy revealed the pre-ignition products to include off-stoichiometric nitrides (TiN x ) and oxynitride skin (TiO x N y ). The formation of the new TiN and Ti 2 N products before ignition was attributed to the diffusion of highly polarized active N atoms into the mechanically activated clean surfaces of Ti, followed by local reaction. This local reaction is likely promoted by numerous cycles of induced local temperature rise and rapid quenching, large surface area and accumulation of deformation defects. After the exothermic ignition, there was rapid nucleation of new TiN crystals, and simultaneous growth of the pre-existing TiN and the newly formed TiN crystals. This understanding explains the reaction pathways leading to the formation of small proportions of TiN and very minor amounts of Ti 2 N before ignition and the thin-plated TiN after ignition. . (2018). Understanding reaction sequences and mechanisms during synthesis of nanocrystalline Ti2N and TiN via magnetically controlled ball milling of Ti in nitrogen. ABSTRACTMechanically induced reactive synthesis of TiN via magnetically controlled ball milling of titanium under nitrogen gas was investigated using X-ray diffraction, advanced electron microscopy and Raman spectroscopy. Ball milling of titanium powder with nitrogen gas was performed in Uni-Ball-Mill, with external temperature of the vial and initial pressures of the nitrogen gas monitored, while the milled samples were taken out periodically, both before and after detection of an exothermic ignition point. Before ignition, nitrogen-enriched Ti, small proportions of TiN and very minor amounts of Ti2N are formed, in addition to the heavily deformed Ti. Raman spectroscopy revealed the preignition products to include off-stoichiometric nitrides (TiNx) and oxynitride skin (TiOxNy). The formation of the new TiN and Ti2N products before ignition was attributed to the diffusion of highly polarized active N atoms into the mechanically activated clean surfaces of Ti, followed by local reaction. This local reaction is likely promoted by numerous cycles of induced local temperature rise and rapid quenching, large surface area and accumulation of deformation defects. After the exothermic ignition, there was rapid nucleation of new TiN crystals, and simultaneous growth of the pre-existing TiN and the newly formed TiN crystals. This understanding explains the ...

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Section: Introductionsupporting

confidence: 64%

Section: Materials and Experimental Procedurescontrasting

confidence: 53%

Understanding reaction sequences and mechanisms during synthesis of nanocrystalline Ti2N and TiN via magnetically controlled ball milling of Ti in nitrogen

2017

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“…Nevertheless, the local temperature of ball milling was as high as 2773 K [35]. Previous studies have shown that Ti+C powder started to nucleate at 150-250°C after 36 h of milling [34]. This was an indication that the rate-controlling step was chemical diffusion of C during milling prior to combustion [6,31,52].…”

Section: Resultsmentioning

confidence: 99%

“…Wu et al [33] suggested a transitional bonded state (Ti···C) plays an important role in reducing the ignition temperature for a combustion reaction during the mechanosynthesis process. Oghenevweta et al [28,34] proposed a dual mechanism of MSR involving a rapid high temperature nucleation of new TiC with local melting of unreacted Ti and the growth of pre-existing nano-TiC.…”

Section: Introductionmentioning

confidence: 99%

“…Note that it usually required some tens of hours to obtain stoichiometric TiC depending on the type of mill [27] such as vibro-mill [30,35], magneto ball mill [28,31,32,34,36] and planetary ball mill [6,[37][38][39][40]. Specifically, the incubation period before a MSR was 37 h in [28,34], 70 h in [32] and 71 h in [31,36]. Up to now, minimum synthesis time in planetary ball mill is within 35 min [39].…”

Section: Introductionmentioning

confidence: 99%

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Fast and efficient approach to synthesis of ultra-fine TiC powder

Changjiang

2019

Mater. Res. Express

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A fast and large scalable process to produce TiC powder was obtained using a horizontal rotary ball mill within 60 min via a mechanically induced self-propagating reaction (MSR). The as-synthesized TiC particles have well-defined crystals structure and the median diameter of ∼1 μm with less impurity due to short duration of milling. The mechanism for the acceleration of MSR was investigated in detail. The graphene nano-platelets are exfoliated from graphite by ultra-high-energy of the horizontal rotary ball mill after less than 30 min of milling, which plays a crucial role in formation of leaf-like nanoplatelets with Ti lamella by ball collision. At the same time, the ultra-highenergy of ball milling can boost self-prorogating reaction in a short duration of milling.

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Synthesis of nanostructured titanium carbide (TiC) from bitumen coke by mechanical alloying process

Xing,

Gieleciak,

Chen

2024

Can J Chem Eng

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This study explored synthesizing titanium carbide (TiC) from bitumen coke using mechanical alloying. Initially, raw bitumen coke (5.9 wt.% sulphur) from delayed coking was desulphurized to produce low sulphur coke with a sulphur content of 0.2 wt.% for comparison purposes. Both high and low sulphur coke samples were mechanically alloyed with titanium (Ti) powder in a planetary ball mill under various conditions (milling time, milling speed, and ball‐to‐material ratios [BMR]). TiC was successfully produced from both high sulphur and low sulphur coke samples. The formation of TiC was confirmed by X‐ray diffraction (XRD) analysis. The effects of the experimental parameters on the production of TiC were evaluated. The experimental results showed that the high sulphur coke and Ti were converted into TiC after 10 h milling, whereas the low sulphur coke and Ti were converted into TiC much faster (after 5 h milling) at the same milling speed and BMR. Under the same milling time and BMR, the high sulphur coke and Ti were converted into TiC at 400 rpm, whereas the low sulphur coke and Ti were converted into TiC at 300 rpm. In addition, the high sulphur coke and Ti were converted into TiC when the BMR was 60:1, and the low sulphur coke and Ti were converted into TiC when the BMR was 40:1 under the same milling time and speed. Overall, preliminary results suggest that the conversion of low sulphur coke samples is easier and requires less energy to produce TiC compared to the high sulphur coke samples.

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Early stages of phase formation before the ignition peak during mechanically induced self-propagating reactions (MSRs) of titanium and graphite

Cited by 16 publications

References 46 publications

Understanding reaction sequences and mechanisms during synthesis of nanocrystalline Ti2N and TiN via magnetically controlled ball milling of Ti in nitrogen

Understanding reaction sequences and mechanisms during synthesis of nanocrystalline Ti2N and TiN via magnetically controlled ball milling of Ti in nitrogen

Fast and efficient approach to synthesis of ultra-fine TiC powder

Synthesis of nanostructured titanium carbide (TiC) from bitumen coke by mechanical alloying process

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