Thermodynamic Pattern Selection in the Stripes Generated Periodically During the (Zn) – Single Crystal Growth

2013 ◽  
Vol 58 (2) ◽  
pp. 309-313
Author(s):  
W. Wołczynski
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Single Crystal ◽  
Selection Criterion ◽  
Single Crystal Growth ◽  
Marginal Stability ◽  
Pattern Selection ◽  
Minimum Entropy ◽  
Solid Liquid Interface ◽  
Solid Liquid

The (Zn) - hexagonal single crystal growth was performed by the Bridgman system. Some eutectic stripes were generated periodically in the single crystal. The stripes consisted of the strengthening inter-metallic compound, Zn16Ti and (Zn) - solid solution. Two morphology transitions were recorded. At the first threshold growth rate, L-shape irregular rods transformed into regular lamellar structure. The transition was accompanied by the irregular into regular morphology alteration. The regular lamella into regular rods transition occurred at the second threshold growth rate. The new, proposed thermodynamic pattern selection criterion (PSC) of the lower minimum entropy production was applied to describe the structural transitions. The solid/liquid interface perturbation of the (Zn) - phase was referred to the marginal stability.

scholarly journals Effect of Composition on the Growth of Single Crystals of (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 by Solid State Crystal Growth

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2357 ◽  
Author(s):  
Le ◽  
Fisher ◽  
Moon
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Solid State ◽  
Single Crystal ◽  
Single Crystals ◽  
Grain Growth ◽  
Ceramic Powder ◽  
Single Crystal Growth ◽  
Crystal Growth Rate ◽  
Mixed Control

The (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs. electric field behaviour. Use of single crystals instead of polycrystalline ceramics may lead to further improvement in piezoelectric properties but work on single crystal growth in this system is limited. In particular, the effect of composition on single crystal growth has yet to be studied. In this work, single crystals of (NBT-100xST) with x = 0.00, 0.05, 0.10 and 0.20 were grown using the method of Solid State Crystal Growth. [001]-oriented SrTiO3 single crystal seeds were embedded in (NBT-100xST) ceramic powder, which was then pressed to form pellets and sintered at 1200 °C for 5 min–50 h. Single crystal growth rate, matrix grain growth rate and sample microstructure were examined using scanning and transmission electron microscopy. The results indicate that the highest single crystal growth rate was obtained at x = 0.20. The mixed control theory of grain growth is used to explain the single crystal and matrix grain growth behaviour.

SiC Single Crystal Growth Rate Measurement by In-Situ Observation using the Transmission X-Ray Technique

2000 ◽  
Vol 338-342 ◽  
pp. 75-78 ◽  
Author(s):  
Naoki Oyanagi ◽  
Shin Ichi Nishizawa ◽  
Tomohisa Kato ◽  
Hirotaka Yamaguchi ◽  
Kazuo Arai
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
Crystal Growth Rate ◽  
In Situ Observation ◽  
Rate Measurement ◽  
X Ray ◽  
Growth Rate Measurement

New Crucible Design for SiC Single Crystal Growth by Sublimation

2000 ◽  
Vol 640 ◽  
Author(s):  
Shin-ichi Nishizawa ◽  
Hirotaka Yamaguchi ◽  
Tomohisa Kato ◽  
M. Nasir Khan ◽  
Kazuo Arai ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Growth Rate ◽  
Crystal Growth ◽  
Single Crystal ◽  
Flat Surface ◽  
Single Crystal Growth ◽  
Crystal Growth Rate ◽  
Bulk Single Crystal ◽  
High Quality ◽  
Better Than

ABSTRACTSiC bulk single crystal growth by sublimation was investigated. A new crucible design, double-walled crucible, was proposed, and its effect was confirmed numerically and experimentally. On the point of heat transfer in a growth cavity, double-walled crucible is better than conventional crucible. With a double-walled crucible, temperature of seed and source surfaces could be kept constant with better uniformity than that with a conventional crucible. It was deduced that a crystal growth rate could be kept constant with flat surface. Furthermore, in case of a double walled crucible, crystal enlarged rapidly with less inclusion. As the results, a double-walled crucible is useful to grow high quality SiC single crystal by sublimation.

Solidification of YBa2Cu3O6+δ: Part I. Morphology

1998 ◽  
Vol 13 (3) ◽  
pp. 565-573 ◽  
Author(s):  
Hua Shen ◽  
Merton C. Flemings ◽  
Michael J. Cima ◽  
John Haggerty ◽  
Shoichi Honjo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Single Crystal ◽  
Dendritic Growth ◽  
Maximum Growth ◽  
Single Crystal Growth ◽  
Maximum Growth Rate ◽  
Growth Interface ◽  
Particle Spacing ◽  
Microstructural Examination

A new quenching technique was used for detailed microstructural examination of quenched YBa2Cu3O6+δ/liquid interfaces. The examination revealed that the growth rate and the amount of excess Y2BaCuO5 (211) had a strong influence on the growth morphology of YBa2Cu3O6+δ (123). The maximum growth rate at which single crystal growth could be obtained increased from 1 μm/s to 1.5 μm/s as excess 211 content increased from 0 to 20 wt. %. It then decreased to 1 μm/s as excess 211 increased to 40 wt. %. Dendritic growth with distinguishable secondary arms occurred for stoichiometric 123 samples in the regime of cellular/dendritic growth. A highly curved 123 envelope was formed on 211 particles located at the 123 growth interface for stoichiometric 123 samples in the regime of single crystal growth. The microscopic 123 growth interface became flat as excess 211 content increased to 20 wt. %. The engulfment of 211 particles into 123 matrix is discussed based on detailed microstructural examination. It is found that the formation of a small highly curved 123 envelope on 211 particles for stoichiometric 123 samples is due to the large 211 particle spacing.

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