Synthesis and Growth Mechanism of Silicon Nitride Nanostructures

2005 ◽  
Vol 475-479 ◽  
pp. 1239-1242 ◽  
Author(s):  
Zhi Peng Xie ◽  
Wei You Yang ◽  
He Zhuo Miao ◽  
Li Gong Zhang ◽  
Li Nan An
Keyword(s):  
Silicon Nitride ◽  
Single Crystals ◽  
Growth Mechanism ◽  
Stacking Faults ◽  
Entire Length ◽  
New Method ◽  
Polymeric Precursor ◽  
Uniform Thickness ◽  
Solid Reaction ◽  
Solid Liquid

A new method to synthesize Si3N4 nanostructures via catalyst-assisted polymeric precursor pyrolysis is present in this article. The as-prepared nanobelts are single crystals with a uniform thickness and width along the entire length, and contain no detectable defects such as dislocations or stacking faults. The thickness and width of Si3N4 nanobelts range from 40 to 60 nm and 600 to 1200 nm, respectively, and the lengths can be up to several millimeters. The growth directions of a-Si3N4 nanobelts are [101] and [100]. A solid-liquid-solid and gas-solid reaction/crystallization is proposed for the growth of S3N4 nonastructures.

Stacking faults in deformed α-silicon nitride single crystals

1993 ◽  
Vol 51 ◽  
pp. 916-917
Author(s):  
H. Suematsu ◽  
J. J. Petrovic ◽  
T. E. Mitchell
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Single Crystals ◽  
Stacking Faults ◽  
High Strength ◽  
Secondary Phase ◽  
High Resolution Electron Microscopy ◽  
Diffusional Creep ◽  
Dislocation Slip ◽  
High Temperature Strength

Silicon nitride(Si3N4) is well known for its high toughness and strength. This is the reason why it is selected for ceramic turbo charger rotors in automobile engines. However, the high strength of most sintered Si3N4 products drops above 1200°C because sintering aids like Y2O3 and MgO are required which form glassy phases with low melting points on the grain boundaries. This secondary phase degrades the high temperature characteristics of Si3N4. In order to overcome this deficiency, much work has been reported which aims at crystallizing or removing the glassy phase. If this aim could be successful, resulting in an increase in high temperature strength, other processes would determine the high temperature performance of Si3N4, such as diffusional creep and dislocation slip. Line and planar defects in Si3N4 play an important role in such the processes particularly in slip, however, available knowledge about them is limited. In the present work, stacking faults in deformed Si3N4 single crystals are investigated using high resolution electron microscopy(HREM).

scholarly journals Structural modulation in potassium birnessite single crystals

2021 ◽  
Author(s):  
Liliia D. Kulish ◽  
Pavan Nukala ◽  
Rick Scholtens ◽  
A. G. Mike Uiterwijk ◽  
Ruben Hamming-Green ◽  
...  
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Charge Ordering ◽  
Atomic Resolution ◽  
Structural Modulation

The largest single crystals of potassium birnessite thus far reported are grown. The structure is studied at atomic resolution. Mn3+/Mn4+ charge ordering, structural modulation and stacking faults are found.

scholarly journals Numerical Analysis of Difficulties of Growing Large-Size Bulk β-Ga2O3 Single Crystals with the Czochralski Method

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Xia Tang ◽  
Botao Liu ◽  
Yue Yu ◽  
Sheng Liu ◽  
Bing Gao
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Czochralski Method ◽  
Liquid Interface ◽  
Spiral Growth ◽  
Growth Time ◽  
Large Size ◽  
Crystal Diameter ◽  
Solid Liquid Interface ◽  
Solid Liquid

The difficulties in growing large-size bulk β-Ga2O3 single crystals with the Czochralski method were numerically analyzed. The flow and temperature fields for crystals that were four and six inches in diameter were studied. When the crystal diameter is large and the crucible space becomes small, the flow field near the crystal edge becomes poorly controlled, which results in an unreasonable temperature field, which makes the interface velocity very sensitive to the phase boundary shape. The effect of seed rotation with increasing crystal diameter was also studied. With the increase in crystal diameter, the effect of seed rotation causes more uneven temperature distribution. The difficulty of growing large-size bulk β-Ga2O3 single crystals with the Czochralski method is caused by spiral growth. By using dynamic mesh technology to update the crystal growth interface, the calculation results show that the solid–liquid interface of the four-inch crystal is slightly convex and the center is slightly concave. With the increase of crystal growth time, the symmetry of cylindrical crystal will be broken, which will lead to spiral growth. The numerical results of the six-inch crystal show that the whole solid–liquid interface is concave and unstable, which is not conducive to crystal growth.

scholarly journals Clustering-Based Component Fraction Estimation in Solid–Liquid Two-Phase Flow in Dredging Engineering

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5697
Author(s):  
Chang Sun ◽  
Shihong Yue ◽  
Qi Li ◽  
Huaxiang Wang
Keyword(s):  
Clustering Algorithm ◽  
Two Phase Flow ◽  
Low Cost ◽  
Fast Response ◽  
New Method ◽  
Phase Flow ◽  
Reference Distribution ◽  
Two Phase ◽  
Long Time ◽  
Solid Liquid

Component fraction (CF) is one of the most important parameters in multiple-phase flow. Due to the complexity of the solid–liquid two-phase flow, the CF estimation remains unsolved both in scientific research and industrial application for a long time. Electrical resistance tomography (ERT) is an advanced type of conductivity detection technique due to its low-cost, fast-response, non-invasive, and non-radiation characteristics. However, when the existing ERT method is used to measure the CF value in solid–liquid two-phase flow in dredging engineering, there are at least three problems: (1) the dependence of reference distribution whose CF value is zero; (2) the size of the detected objects may be too small to be found by ERT; and (3) there is no efficient way to estimate the effect of artifacts in ERT. In this paper, we proposed a method based on the clustering technique, where a fast-fuzzy clustering algorithm is used to partition the ERT image to three clusters that respond to liquid, solid phases, and their mixtures and artifacts, respectively. The clustering algorithm does not need any reference distribution in the CF estimation. In the case of small solid objects or artifacts, the CF value remains effectively computed by prior information. To validate the new method, a group of typical CF estimations in dredging engineering were implemented. Results show that the new method can effectively overcome the limitations of the existing method, and can provide a practical and more accurate way for CF estimation.

Lattice-constant and stress measurement in single crystals: a new method

2005 ◽  
Vol 38 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Balder Ortner
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Lattice Constant ◽  
Stress Measurement ◽  
New Method ◽  
Lattice Plane ◽  
X Ray ◽  
Advantages And Disadvantages

A method for the X-ray determination of lattice-plane distances is given. Similar to Bond's method, it is based on the measurement of rocking curves, with some advantages and disadvantages compared with the former method. The new method is especially designed for single-crystal stress measurement. Its usefulness is demonstrated in two examples of lattice-constant and stress measurement.

Extrinsic stacking faults and twinning in hadfield manganese steel single crystals

2001 ◽  
Vol 44 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Ibrahim Karaman ◽  
H Sehitoglu ◽  
Y.I Chumlyakov ◽  
H.J Maier ◽  
I.V Kireeva
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Manganese Steel

Characterization of Defect Structures in 3C-SiC Single Crystals Using Synchrotron White Beam X-ray Topography

1996 ◽  
Vol 423 ◽  
Author(s):  
W. Huang ◽  
M. Dudley ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Interference Microscopy ◽  
Defect Structures ◽  
Growth Sector ◽  
X Ray ◽  
Partial Dislocations ◽  
White Beam ◽  
Transmission And Reflection

AbstractDefect structures in (111) 3C-SiC single crystals, grown using the Baikov technique, have been studied using Synchrotron White Beam X-ray Topography (SWBXT). The major types of defects include complex growth sector boundary structures, double positioning twins, stacking faults on { 111 } planes, inclusions and dislocations (including growth dislocations and partial dislocations bounding stacking faults). Detailed stacking fault and double positioning twin configurations are determined using a combination of Nomarski interference microscopy, SEM and white beam x-ray topography in both transmission and reflection geometries. Possible defect generation phenomena are discussed.

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