Different Effect of the Atmospheres on the Phase Formation and Performance of Li4Ti5O12Prepared from Ball-Milling-Assisted Solid-Phase Reaction with Pristine and Carbon-Precoated TiO2as Starting Materials

2011 ◽  
Vol 115 (11) ◽  
pp. 4943-4952 ◽  
Author(s):  
Tao Yuan ◽  
Rui Cai ◽  
Zongping Shao
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hui Yan ◽  
Ying Deng ◽  
Yong Yao Su ◽  
Shan Jiang ◽  
Qiao Wang Chen ◽  
...  

Ti(C, N)-based cermet materials represent the best choice of materials for the manufacturing industry and military products. In this study, we use cubic β-cobalt(β-Co) as the binder phase to strengthen constructed cermets. At the same time, to optimize the microstructure, (Ti, W, Mo, Ta) (C, N) powders are added to form two kinds of core-rim morphologies. Here, β-cobalt powders with face-centered cubic structures are obtained by the solid-phase reaction of high-energy ball milling. A solid-phase chemical reaction and a carbothermic reduction-nitridation method are used to prepare the (Ti, W, Mo, Ta) (C, N) powders. In our process, first we mix the cobalt and (Ti, W, Mo, Ta) (C, N) powders; then we press the powder mixtures into rectangular samples and sinter them in a pressure sintering furnace to obtain Ti(C, N)-based cermets with two kinds of core-rim structure, that is, black core/white rim and white core/gray rim. The results show that the new cermets demonstrate excellent toughness and performance.


1995 ◽  
Vol 402 ◽  
Author(s):  
D. B. Aldrich ◽  
Y. L. Chen ◽  
D. E. Sayers ◽  
R. J. Nemanich

AbstractThe effect of Si1−xGex alloy composition on the titanium germanosilicide phase formation sequence during the Ti-Si1−xGex solid phase reaction was examined. For the Ti-Si reaction the initial formation of C49 TiSi2 is followed, at higher temperatures, by the formation of C54 TiSi2. For the Ti-Ge reaction the initial formation of Ti6Ge5 is followed, at higher temperatures, by the formation of C54 TiGe2. It was determined that the Ti-Si1−xGex reaction follows three different reaction paths depending on the composition of the initial Si1−xGex alloy. For Si rich Si1−xGex alloys the Ti-Si1−xGex reaction follows a “Ti-Si like” reaction path (Ti+M ↠ C49 TiM2 ↠ C54 TiM2, where M = Si1−xGex). For Ge rich Si1−xGex alloys the reaction follows a “Ti-Ge like” reaction path (Ti+M ↠ Ti6M5 ↠ C54 TiM2). Both Ti6M5 and C49 TiM2 form during the reaction of titanium with Si1−xGex alloys in an intermediate composition range. Properties of the final C54 phase were observed to be strongly dependent on the phase formation sequence. Smooth continuous C54 titanium germanosilicide forms during the “Ti-Si like” reaction and discontinuous islanded C54 titanium germanosilicide forms during the “Ti-Ge like” reaction. An optimum Si1−xGex alloy composition range of 0.00 ≤ x ≤ 0.36 was determined for the formation of continuous- low-resistivity- C54 titanium germanosilicide films from the solid phase reaction of Ti and Si1−xGex alloy.


1999 ◽  
Vol 580 ◽  
Author(s):  
C.C. Theron ◽  
A. Falepin ◽  
S. Degroote ◽  
J. Dekoster ◽  
A. Vantomme ◽  
...  

AbstractBy analogy to reactive deposition epitaxy and titanium interlayer mediated epitaxy experiments, an attempt has been made to constrain the supply of reactants to the reaction interface in the solid phase reaction between Fe and Si. The goal being to change the normal phase formation sequence by using a suitable diffusion barrier, so that β-FeSi2 forms directly. Both Fe-V and Fe-Zr diffusion barriers were used to constrain the supply of the two reactants during Fe-silicide formation. Measurements with these barriers, show first phase formation of β-FeSi2, but direct formation of 3-FeSi2 as first phase has not been observed. In the case of the Fe-V diffusion barrier it was shown that the use of the diffusion barrier resulted in smoother layers of β-FeSi2 than could be formed by direct reaction of Fe on Si. In the case of the Fe-Zr barrier it is found that the barrier fails structurally at high temperatures. While it does prohibit Fe diffusion at low annealing temperatures, significant Si diffusion occurs prior to ε-FeSi formation.


1995 ◽  
Vol 10 (11) ◽  
pp. 2849-2863 ◽  
Author(s):  
D.B. Aldrich ◽  
Y.L. Chen ◽  
D.E. Sayers ◽  
R.J. Nemanich ◽  
S.P. Ashburn ◽  
...  

The effects of Si1−xGex alloy composition on the Ti-Si1−xGex solid phase reaction have been examined. Specifically, effects on the titanium gcrmanosilicide phase formation sequence. C54 Ti(Si1−yGey)2 nucleation temperature, and C54 Ti(Si1−yGey)2 morphology were examined. It was determined that the Ti-Si1−xGex reaction follows a “Ti-Si-like” reaction path for Si-rich Si1−xGex alloys and follows a “Ti-Ge-like” reaction path for Ge-rich Si1−xGex alloys. The coexistence of multiple titanium germanosilicide phases was observed during Ti-Si1−xGex reactions for Si1−xGex alloys in an intermediate composition range. The morphology and stability of the resulting C54 germanosilicides were directly correlated to the Ti-Si1−xGex reaction path. Smooth continuous C54 titanium germanosilicide was formed for samples with Si1−xGex compositions in the “Ti-Si-like” regime. Discontinuous islanded C54 germanosilicides were formed for samples with Si1−xGex compositions in the mixed phase and “Ti-Ge-like” regimes. Using rapid thermal annealing techniques, it was found that the C54 titanium germanosilicides were stable to higher temperatures. This indicated that the morphological degradation occurs after C54 phase formation. The C54 Ti(Si1−xGex)2 formation temperature was examined as a function of alloy composition and was found to decrease by ≍ 70 °C as the composition approached x ≍ 0.5. An optimum Si1−xGex alloy composition range of 0 ⋚ x ⋚ 0.36 was determined for the formation of stable-continuous-low-resistivity-C54 titanium germanosilicide films from the solid phase reaction of Ti and Si1−xGex alloy. The results were described in terms of the relevant nucleation processes.


1995 ◽  
Vol 402 ◽  
Author(s):  
G Y. Molnár ◽  
G. Pető ◽  
E. Zsoldos ◽  
Z. E. Horváth ◽  
N. Q. Khánh

AbstractThe solid phase reaction of Fe thin films with (111) Si substrate was investigated at constant annealing temperature and time (700°C, 7 minutes) as a function of the initial iron film thickness (from 5 nm to 27.5 um in 2.5 nm steps). The formed phases were analysed by X-ray diffraction, Rutherford backscattering and transmission electron microscopy and optical microscopy.After annealing FeSi phase was detected in the thinner samples. Samples with Fe layers thicker than 12.5 nm contained a β-FeSi2 phase. This special phase sequence was explained with the help of a nucleation controlled phase formation model, taking into consideration the critical radius of nuclei of the new phase. The advantages of using the film thickness as a variable during investigation of solid phase thin film reactions and the probable substrate effects are also discussed.


2010 ◽  
Vol 154-155 ◽  
pp. 184-190
Author(s):  
Jun Zhao ◽  
Shi Bo Ma ◽  
Jin Ma

Adopted the method of vacuum sintering liquid-solid phase reaction to prepare metal-ceramic coating, focused on the microstructure, phase composition and performance of the coating, which was prepared by two kinds of binding phase materials. The results showed that: the coating, obtained by reaction sintering of cobalt-boron alloy and self-molten Fe-based alloy composite binding phase, had compact structure. WC hard phase of the coating didn’t have phenomena of burning loss, decarbonization, agglomeration and growth. WC phase was completely circle-molten by γ-Co primary solid solution and γ-(Co, Fe, Ni) supersaturated solid solution. Newly generated granular and lath-shape hard phase evenly dispersed in binding phase, which increased the wear resistance of the coating substantially. The relative abrasion of ceramic-metal coating prepared by composite binding phase was nearly 50% lower than the one prepared by Fe-based binding phase.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.


2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.


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