Solid-Liquid Reactions in the Synthesis of High-Purity Bismuth Compounds

2020 ◽  
Keyword(s):  
High Purity ◽  
Bismuth Compounds ◽  
Solid Liquid

Evolution of the Solidification Microstructure of Rheocast High Purity Aluminium

2012 ◽  
Vol 192-193 ◽  
pp. 109-115 ◽  
Author(s):  
Sarah George ◽  
Robert Knutsen
Keyword(s):  
High Purity ◽  
Liquid Interface ◽  
Cellular Growth ◽  
Solidification Mode ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Semi Solid ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid

High purity aluminium has been successfully rheocast using the CSIR-RCS system combined with high pressure die casting. Analysis of the as-cast microstructure by SEM and EBSD revealed the presence of in-grain substructures. These morphological features show that the overall growth mode of the globular grains during rheocasting is planar, but the presence of these features indicates that the solidification mode is cellular at some stages during the slurry production process. Cellular solidification is associated with unstable growth at the solid-liquid interface and is initiated and exacerbated by solute gradients between the melt and the newly formed solid. This high purity alloy exhibits the same cellular growth, indicating that even minor solute variations have an effect on the stability of the solid-liquid interface and, hence, the mode of solidification during semi-solid rheocasting.

The Role of Fe on the Grain Refinement of High Purity Aluminium

2012 ◽  
Vol 538-541 ◽  
pp. 2264-2268 ◽  
Author(s):  
Yi Jie Zhang ◽  
Nai Heng Ma ◽  
Brian J. McKay ◽  
Xian Feng Li ◽  
Hao Wei Wang
Keyword(s):  
Grain Refinement ◽  
High Purity ◽  
Solute Concentration ◽  
Grain Structure ◽  
Grain Refiner ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Solid Liquid Interface ◽  
Solid Liquid

The role of Fe on the grain refinement of high purity aluminium (HPAl) was investigated after adding commercial Al-5Ti-1B grain refiner rod. Experimental results show that with a 0.08% Fe addition, the grain structure at chill zone of the HPAl sample changes from coarse to fine equiaxed grains. More importantly, the grain size observed at the centre of the HPAl sample decreased from 500±50µm to 206±30µm. The improvement has been attributed to the interfacial segregation and solute concentration of the Fe at the solid-liquid interface.

Production by solid/liquid reaction and characterization of high purity MgB2 powders and thick films for superconducting application

2004 ◽  
Vol 24 (6) ◽  
pp. 1837-1840 ◽  
Author(s):  
S. Bodoardo ◽  
C. Portesi ◽  
P. Fino ◽  
R. Gonnelli ◽  
M. Rajteri ◽  
...  
Keyword(s):  
High Purity ◽  
Thick Films ◽  
Liquid Reaction ◽  
Solid Liquid

scholarly journals Influence of the modes of shaping of sand-resin shellis on quality of the produced castings

2019 ◽  
pp. 13-18
Author(s):  
V. Yu. Kulikov ◽  
S. S. Kvon ◽  
T. V. Kovalyova ◽  
E. P. Shcherbakova ◽  
E. N. Eremin
Keyword(s):  
High Purity ◽  
Static Pressure ◽  
Variable Pressure ◽  
Internal Defects ◽  
Aggregate State ◽  
Press Plate ◽  
Thermal Influence ◽  
Solid Liquid

Resin in sand-resin mixes in the course of heating at production of casting shell molds undergoes changes of a state: solid – liquid – solid. For the purpose of increase in durability and decrease in contents of binding (pulverbakelit) in mix when forming a shell, along with thermal influence, the static pressure, the resines changing in compliance with change of aggregate state was used. Basic pressure is 0.25 MPas and moves through a press plate right after filling of mix on heated up to 230 °C model plate. In 10 seconds pressure increases up to 0.35 MPas. And in 10 seconds pressure goes down to 0.2 MPas. It is experimentally defined that the castings received in the shell forms made with use of variable pressure have the minimum and uniform internal tension. Also researches showed that such castings have high purity of a surface (Rz 70–80) and lack of internal defects.

scholarly journals Study on Solidification Structure Evolution of Direct-Chill Casting High Purity Copper Billet Using Cellular Automaton-Finite Element Method

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1052
Author(s):  
Yonghui Jia ◽  
Dazhi Zhao ◽  
Chunyu Li ◽  
Lei Bao ◽  
Qichi Le ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Grain Size ◽  
Finite Element ◽  
High Purity ◽  
Direct Chill ◽  
Solidification Structure ◽  
Structure Evolution ◽  
Dc Casting ◽  
Solid Liquid ◽  
Purity Copper

A heat transfer model and a cellular Automation-Finite Element (CAFE) coupling model were established to analyze the solid/liquid (S/L) interface and solidification structure evolution of high purity copper Direct-chill (DC) casting billet under different casting conditions. The simulation and actual experimental results of liquid sump shape and solidification structure were first compared to verify the accuracy of the model. It is proved that the model is effective for simulating the solidification structure of the actual DC casting high purity copper billet. After that, the model was used to predict the solidification structure under different casting temperatures, casting speeds, and heat transfer coefficients. It is shown that, with the increase of casting temperature, the grain size decreases first and then increases. There is a compromise between grain size and its uniformity, and the grain size is more uniform at higher casting temperature. With the increase of casting speed, the depth of liquid sump and the height of the S/L interface increase, but the total grain number of the billet cross-section decreases gradually. As the heat transfer coefficient increases, the depth of the casting liquid sump becomes shallow, but the height of the solid-liquid interface increases and the grain size increases gradually. For the preparation of high purity copper billets with large cross-sectional dimensions by DC casting, a fine solidified structure could be obtained by appropriately reducing the casting speed and cooling intensity.

Solid–Liquid Reaction Synthesis of High-Purity Potassium Hexathionate and Its Antibacterial Properties

2016 ◽  
Vol 69 (3) ◽  
pp. 267
Author(s):  
Guofang Li ◽  
Yahui Xia ◽  
Yanbao Zhao ◽  
Ping Li ◽  
Fuqiang Zhang ◽  
...  
Keyword(s):  
High Purity ◽  
Potassium Hydroxide ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Sodium Thiosulfate ◽  
Antibacterial Properties ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Liquid Reaction ◽  
Solid Liquid

Hexathionate, an intermediate in the oxidation process of inorganic sulfur compounds, plays important roles in different fields of chemistry, chemical technology, and biology. To achieve innovative results in different fields related to polythionates, the use of hexathionate is crucial, however, it is not yet commercially available. Herein, we report a simple and convenient method to prepare high-purity potassium hexathionate. Hexathionic acid was easily synthesised through a solid–liquid reaction between sodium thiosulfate (solid) and disulfur dichloride. The potassium salt crude product was obtained by neutralising hexathionate acid with potassium hydroxide, and was purified successively using 0.1 M sulfuric acid and 0.5 M hydrochloric acid. A high product purity of 99.8 % (titrimetric analysis, 98.81 %) was obtained. The antibacterial activities of potassium hexathionate against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa) were determined by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses and the cup diffusion method. Potassium hexathionate displayed more effective antibacterial activities against P. aeruginosa than S. aureus. The MICs against P. aeruginosa and S. aureus were 1.95 and 125 µg mL–1, respectively. The corresponding MBC value against P. aeruginosa was 1000 µg mL–1. Furthermore, the duration of the antimicrobial activity, determined by the cup diffusion, shows the potential of potassium hexathionate as a sustained antibacterial candidate. However, there is no bactericidal activity against S. aureus in the concentration range tested.

FURTHER OBSERVATIONS ON DENDRITIC GROWTH IN METALS

1952 ◽  
Vol 30 (5) ◽  
pp. 488-502 ◽  
Author(s):  
F. Weinberg ◽  
Bruce Chalmers
Keyword(s):  
High Purity ◽  
Dendritic Growth ◽  
Cell Structure ◽  
Dendrite Growth ◽  
Initial Part ◽  
Lead Crystal ◽  
Initial Formation ◽  
A Cell ◽  
Solid Liquid Interface ◽  
Solid Liquid

The direction of dendrite growth has been determined as a function of crystallographic orientation for high purity tin and zinc, using a single crystal decanting technique. Measurements are reported on the rate of dendrite growth in lead, and the spacing between dendrite rows of a lead crystal for varying amounts of supercooling. The initial formation of dendrite stalks appears related to a cell structure observed on the exposed solid liquid interface.A mechanism of dendrite growth is advanced and compared with the experimental observations. It is shown that dendritic growth occurs only during the initial part of solidification. The remainder is a result of the nondendritic advance of a solid liquid interface with some thickening of the existing branches.

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