Effect of the Crystallization Process and Solid State Storage on the Physico-Chemical Properties of Scale-Up Lots of CI-936

1991 ◽  
Vol 17 (18) ◽  
pp. 2411-2438 ◽  
Author(s):  
Hua-Pin Huang ◽  
K. S. Murthy ◽  
Isaac Ghebre-Sellassie
2020 ◽  
Vol 49 (20) ◽  
pp. 6566-6571 ◽  
Author(s):  
Daniela Lalli ◽  
Stefano Marchesi ◽  
Fabio Carniato ◽  
Chiara Bisio ◽  
Lorenzo Tei ◽  
...  

A combination of solid-state NMR and 1H-NMR relaxometric investigations has been employed to characterize the structure and physico-chemical properties of a novel synthetic saponite intercalated with Gd(iii) and Y(iii) chelates.


2012 ◽  
Vol 733 ◽  
pp. 84-87 ◽  
Author(s):  
Viktor Majerník ◽  
Jozef Krištiak ◽  
Ondrej Šauša ◽  
Martina Iskrová-Miklošovičová

Positron annihilation lifetime measurements have been performed on three molecular systems: propylene carbonate, salol and m-toluidine at the temperature range from 20 K up to 300 K. The time dependences of the orthopositronium lifetime and intensity have been observed at the temperature range between a solid state and the liquid state. These changes can be explained as transitions from the amorphous phase to one or two crystalline phases. The crystallization process from cooled liquid was observed in all three cases at different temperatures on the time scale up to 60 hours.


2019 ◽  
Vol 62 (3) ◽  
pp. 222-227
Author(s):  
A. G. Тyagunov ◽  
Е. Е. Baryshev ◽  
G. V. Tyagunov ◽  
Т. K. Кostina ◽  
K. Yu. Shmakova

At present time, metallurgical wastes are used in metallurgical alloys production more and more. The volume accumulation and increase of return age effect on charge pollution by undesirable elements and nonmetallic inclusions. As a result, structure and properties of the casting inevitably get worse. This circumstance must influence on polytherm’s character of physical properties of the melt, necessary temperature and time parameters of the heat-resistant alloy’s melting accordingly. We have researched the temperature dependences of electrical resistance and kinematic viscosity of liquid heat-resistant composites based оn Ni – Nb – Cr – Mo systems. The critical temperatures were determined for the EP902 alloy. Heating up to these temperatures leads to irreversible changes in direction of the melt improving. Interaction was found between the amount of foundry waste and features of temperature dependences of the melt physico-chemical properties. An increase in the amount of foundry waste using in remelting results in the critical temperatures increasing. Influence of the melt conditions on crystallization process and on the structure of hard metal has been studied. The process of alloy EР902 solidification was researched by differential thermal analysis method. It has shown that the crystallization process starts with extraction of solid solution on the base of γ-phases and ends with forming of the eutectic based on the Ni3Nb intermetallic compound. Heating of the melt over the critical temperature leads to an increase of supercooling and does not effect on the eutectic temperature. The processing mode of the high temperature melt treatment was proposed based on the research results of physico-chemical properties of the liquid metal and process of the melt crystallization. It allows obtaining the highest quality of casting of heat-resistant EР902 alloy, which contains significant amount of foundry waste in the charge. The mechanical tests were implemented for experimental samples melted out by the optimal mode of high-temperature melt treatment (HTTM). Application of HTTM for the melts, contained 50 % of foundry waste in charge, allows obtaining the level of strength and plastic properties exceeding the technical requirements, stabilizing and combining it from melt to melt.


2021 ◽  
pp. 3-8

The aim of this work is to study the areas of glass formation and metastable liquation of the pseudo-ternary system (MgO·Al2O3)-B2O3-SiO2, and study of the crystallization process of glasses of cordierite composition. The crystallization process of glasses of cordierite composition containing B2O3 by a single-stage heat treatment at 1000 oC and 1200 oC, the nature of crystallization, the thermal properties of glasses and glass crystalline materials of the system (MgO·Al2O3)-B2O3-SiO2 were studied. It revealed that during the isolation of a boron-containing solid solution, the residual glassy phase enriched with oxides of MgO and Al2O3, which lead to an increase in the thermal expansion coefficient of the glass phase. The research results provide possibility to synthesize glass-ceramics with certain thermophysical parameters by stopping further glass crystallization at the stage of formation of a certain amount and ratio of the required crystalline and glassy phases.


2003 ◽  
Vol 802 ◽  
Author(s):  
Joe Wong ◽  
Michael Krisch ◽  
Daniel L. Farber ◽  
Florent Occelli ◽  
Adam J. Schwartz ◽  
...  

Plutonium (Pu) is well known to have complex and unique physico-chemical properties [1]. Notably, the pure metal exhibits six solid-state phase transformations with large volume expansions and contractions along the way to the liquid state: α → β → γ → δ → δ' → ε→ liquid. Unalloyed Pu melts at a relatively low temperature ∼640 °C to yield a higher density liquid than that of the solid from which it melts, (Figure 1). Detailed understanding of the properties of plutonium and plutonium-based alloys is critical for the safe handling, utilization, and long-term storage of these important, but highly toxic materials. However, both technical and and safety issues have made experimental observations extremely difficult.


1986 ◽  
Vol 51 (5) ◽  
pp. 1100-1111 ◽  
Author(s):  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Antonín Lyčka ◽  
T. K. Chattopadhyay ◽  
B. Majee ◽  
...  

The paper describes preparation and basic physical and chemical properties of a group of substituted di- and tri(1-butyl)tin(IV) phenoxyacetates and phenylthioacetates of the general formula (RxC6H5-xECH2CO2)nSn(1-C4H9)4-n, where R = H, 2-Cl, 4-Cl, 2-CH3, and 2-OCH3, E means oxygen or sulphur atoms, n = 1 or 2, and x = 1 or 2. From IR spectral data, 13C, 17O, and 119Sn NMR spectra, and from other physico-chemical methods, conclusions are drawn about structure of the compounds in solid state and in solutions of coordinating (hexamethylphosphoric triamide) and non-coordinating solvents (chloroform, carbon tetrachloride, carbon disulphide, benzene). In solid state the tri(1-butyl)tin(IV) compounds form polymeric chains with bidentate bridge carboxylic groups. In non-coordinating solvents these compounds are present as isolated pseudotetrahedral molecules, whereas in hexamethylphosphoric triamide they form complexes with one solvent molecule, the central tin atom exhibiting the trans-trigonally bipyramidal coordination. The di(1-butyl)tin(IV) compounds form, both in solid state and in non-coordinating solvents, monomeric particles containing bidentate chelate carboxylic groups. In hexamethylphosphoric triamide they form complexes with octahedral coordination around the tin atom containing monodentate carboxylic groups and the butyl groups are trans position. In none of the cases studied evidence was obtained for interaction of the oxygen or sulphur atoms of C6H5ECH2 group with the tin atom.


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