Catalyst-assisted synthesis of α-Si3N4 in molten salt

Ding, Jun; Zhu, Hao; Li, Guangqiang; Deng, Chengji; Chai, Zhinan

doi:10.1016/j.ceramint.2015.10.066

Cited by 43 publications

(17 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure (d), (e) displays an SEM image of the droplets (or no droplets) as obtained at the whisker tip. Unwanted phases play a main role in Si 3 N 4 whisker growth by forming liquid droplets (vapor/high liquid/solid) . β‐Si 3 N 4 whiskers with nonuniform hexagonal‐ (or rhombohedral)‐like morphology can be seen in Figure (f), (g) with a length of 0.1–2 µm.…”

Section: Resultsmentioning

confidence: 98%

“…Based on the results obtained, the SiC rod‐like whiskers were synthesized in situ by direct carbothermal reduction of silicon with activated carbon in Ar atmosphere (reaction ). No liquid droplets were found in β‐SiC whisker, indicating that those rod‐like whiskers are formed by a VLS (vapor/low liquid/solid) growth mechanism . The possible reactions (regarding the unwanted phases MgO, Si, SiC, Fe 2 O 3 , Fe 3 O 4 , FeO, Fe, MgCO 3 in Figure ) are as follows:

{normalS normali normalO}_{2 ((), s)} + 2 normalMg = {normalS normali}_{(normalS)} prefix+ 2 normalM normalg normalO

{normalS normali normalO}_{2} + normalC = normalS normali normalO prefix+ normalC normalO

{normalS normali normalO}_{2 ((), s)} + 2 {normalC normalO}_{(normalg)} = {normalS normali}_{(normalS)} + 2 {normalC normalO}_{2 ((), g)}

normalS normali + normalC = SiC

3 {normalF normale}_{2} O_{3 ((), S)} + {normalC normalO}_{(normalg)} = 2 {normalF normale}_{3} O_{4 ((), S)} + {normalC normalO}_{2 ((), g)}

normalF normale ...

…”

Section: Resultsmentioning

confidence: 99%

“…The SiC rod‐like whiskers were synthesized in situ by direct reduction of the synthesized Si 3 N 4 with activated carbon in N 2 atmosphere (reaction ). By the addition of metal sintering aids, the liquid phase Mg–Si–O–N increased (enhanced densification via particle rearrangement) and their hexagonal or rhombohedral whisker shape (Si 3 N 4 ) tended toward a rod‐like shape (β‐SiC) . Based on the results obtained, the Si 3 N 4 whiskers were synthesized in situ by direct nitridation and carbothermal reaction of SiO 2 in N 2 atmosphere (reactions ,15) .…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

Saeedifar

Saeedifar²

2017

Journal of the Chinese Chemical Society

View full text Add to dashboard Cite

SiO 2(activated or mesoporous silica) /Mg (magnesiothermic or metal sintering aid) /C (activated or polymeric carbon) / N 2(atmosphere) systems were used in the one-step synthesis of β-SiC and β-Si 3 N 4 whiskers. In this study, a mixture of the active precursors was allowed to react via a self-sustaining reaction (highenergy ball milling process). Scanning electron micrographs and X-ray diffraction (XRD) analysis showed that the rod-like SiC whiskers (~800 μm) were synthesized in situ by the direct carbothermal reduction of silicon nitride (or silicon) with activated carbon in N 2 (or Ar) atmosphere. The results show that β-Si 3 N 4 (without β-SiC) was fully formed after 5 h of milling with four different morphologies, namely whisker tip (droplet/no droplet) and nonuniform whiskers (short hexagonal/ rhombohedral/rod-like) with a length of 0.1-400 μm. By adding metal sintering aids, the liquid phase Mg-Si-O-N and the rate of carbothermal reduction increased (enhanced densification via particle rearrangement) and their hexagonal whiskers tended to assume a rod-like shape. The effect of the concentration of CO (reduction of α-Fe 2 O 3 to Fe by CO) on the whisker synthesis suggests that, in addition to the concentration of CO, the nature of the family of mesoporous silica/carbon template is an important factor in the synthesis of β-SiC and β-Si 3 N 4 whiskers. The possible chemical reactions were investigated by studying the unwanted phases (MgO

show abstract

Section: Resultsmentioning

confidence: 98%

{normalS normali normalO}_{2 ((), s)} + 2 normalMg = {normalS normali}_{(normalS)} prefix+ 2 normalM normalg normalO

{normalS normali normalO}_{2} + normalC = normalS normali normalO prefix+ normalC normalO

{normalS normali normalO}_{2 ((), s)} + 2 {normalC normalO}_{(normalg)} = {normalS normali}_{(normalS)} + 2 {normalC normalO}_{2 ((), g)}

normalS normali + normalC = SiC

3 {normalF normale}_{2} O_{3 ((), S)} + {normalC normalO}_{(normalg)} = 2 {normalF normale}_{3} O_{4 ((), S)} + {normalC normalO}_{2 ((), g)}

normalF normale ...

…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

Saeedifar

Saeedifar²

2017

Journal of the Chinese Chemical Society

View full text Add to dashboard Cite

show abstract

“…This then results in a shortened reaction time and lower temperatures being required for the synthesis. Recently, MSS have been used for the synthesis of a variety of materials (Ding et al, 2014a(Ding et al, ,b, 2015(Ding et al, , 2016.…”

Section: Molten Salt Synthesis (Mss)mentioning

confidence: 99%

A Comprehensive Review on the Synthesis and Energy Applications of Nano-structured Metal Nitrides

2020

View full text Add to dashboard Cite

Nanosized metal nitrides, due to their chemical characteristics which make them sustainable alternatives to noble metals in catalysis, have drawn the attention of researchers worldwide. Transition metal nitrides are very similar in their method of synthesis, properties, and applications. Their synthetic parameters are considered to be the main factor for determining the effectiveness of metal nitrides in photocatalysis, energy storage devices, remediation of environmental pollutants, gas sensors, and biomedical applications. This review focuses on very recent advances made in synthetic approaches and electrocatalytic applications of metal nitrides. The synthetic approaches will provide an overview of cost of production and consumption of energy and time required for synthesis. Furthermore, some recent techniques that offer new paths for researchers, such as electrochemical, sol-gel, solvothermal, sonochemical, solid-state reaction, chemical synthesis, and many more, are also discussed. Various applications in electrocatalysis, water splitting, lithium ion batteries, and super-capacitors, etc. are summarized. We are confident that this review will provide very useful information for the upcoming community of researchers interested in synthesizing nitrides for various applications.

show abstract

“…According to relevant research, the addition of NaCl, NH 4 Cl, KCl, and other molten salts into the raw reactants could effectively reduce the adiabatic temperature and stabilize the sintering reaction [12][13][14]. Additionally, previous research on the direct nitridation of Si 3 N 4 has shown that the preparation of Si 3 N 4 with high bers content was bene cial to the thermal conductivity of Si 3 N 4 ceramics owing to their low atomic mass, strong interatomic bonding, high modulus, small dielectric constant, high single crystal purity and fewer internal defects in the lattice [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

The effects of Fe and NH4Cl on silicon nitridation

Zhang

Zhu

et al. 2020

Preprint

View full text Add to dashboard Cite

Silicon nitride (Si3N4) with a high α-phase content is in demand due to its higher thermal conductivity for use in heat dissipation bases for electronic devices. However, more needs to be understood about its fibrous growth, therefore, rich fibrous morphologies were synthesized with the assistance of Fe powder and NH4Cl. The effects of these additives on the phase content and fiber morphologies of the products were investigated The results illustrate that the Si3N4 products possess upper and lower layers and that when the Fe powder content is 4 wt% and NH4Cl content is 5 wt%, the Si3N4 fibers have smooth surfaces, uniform diameters, and no floating particles. Moreover, the maximum α-Si3N4 content reached 94.8 wt%, demonstrating an increase in this phase. The double mechanisms of vapor-liquid-solid and vapor-solid are presented as the growth mechanism at the fiber.

show abstract

Catalyst-assisted synthesis of α-Si3N4 in molten salt

Cited by 43 publications

References 24 publications

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

A Comprehensive Review on the Synthesis and Energy Applications of Nano-structured Metal Nitrides

The effects of Fe and NH4Cl on silicon nitridation

Contact Info

Product

Resources

About

Catalyst-assisted synthesis of α-Si3N4 in molten salt

Cited by 43 publications

References 24 publications

Fabrication of SiC and Si3N4Whiskers under Pressurized Ar and N2Atmosphere through High-Energy Ball Milling

Fabrication of SiC and Si3N4Whiskers under Pressurized Ar and N2Atmosphere through High-Energy Ball Milling

A Comprehensive Review on the Synthesis and Energy Applications of Nano-structured Metal Nitrides

The effects of Fe and NH4Cl on silicon nitridation

Contact Info

Product

Resources

About

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling