scholarly journals Application of DSC Method in Studies on Phase Transitions of Ni Superalloys

2017 ◽  
Vol 17 (4) ◽  
pp. 133-136 ◽  
Author(s):  
R. Przeliorz ◽  
J. Piątkowski
Keyword(s):  
Phase Transitions ◽  
Specific Heat ◽  
Protective Atmosphere ◽  
Scanning Calorimetry ◽  
Heating And Cooling ◽  
Complete Melting ◽  
Calorimetric Studies ◽  
Dsc Method ◽  
Dsc Curves

Abstract The paper presents results of calorimetric studies of foundry nickel superalloys: IN100, IN713C, Mar-M247 and ŻS6U. Particular attention was paid to determination of phase transitions temperatures during heating and cooling. The samples were heated to a temperature of 1500°C with a rate of 10°C⋅min-1 and then held at this temperature for 5 min. After a complete melting, the samples were cooled with the same rate. Argon with a purity of 99.99% constituted the protective atmosphere. The sample was placed in an alundum crucible with a capacity of 0.45 cm3. Temperature and heat calibration was carried out based on the melting point of high-purity Ni. The tests were carried out by the differential scanning calorimetry (DSC) using a Multi HTC high-temperature calorimeter from Setaram. Based on the DSC curves, the following temperatures were determined: solidus and liquidus, dissolution and precipitation of the γ’ phase, MC carbides and melting of the γ’/γ eutectic. In the temperature range of 100-1100°C, specific heat capacity of the investigated superalloys was determined. It was found that the IN713C and IN100 alloys exhibit a higher specific heat while compared to the Mar-M247 and ŻS6U alloys.

Specific heats of polymer powders by differential scanning calorimetry

1982 ◽  
Vol 60 (14) ◽  
pp. 1853-1856 ◽  
Author(s):  
Eva I. Vargha-Butler ◽  
A. Wilhelm Neumann ◽  
Hassan A. Hamza
Keyword(s):  
Differential Scanning Calorimetry ◽  
Specific Heat ◽  
Scanning Calorimetry ◽  
Temperature Range ◽  
Specific Heats ◽  
Powdered Form ◽  
Polymer Powders

The specific heats of five polymers were determined by differential scanning calorimetry (DSC) in the temperature range of 300 to 360 K. The measurements were performed with polymers in the form of films, powders, and granules to clarify whether or not DSC specific heat values are dependent on the diminution of the sample. It was found that the specific heats for the bulk and powdered form of the polymer samples are indistinguishable within the error limits, justifying the determination of specific heats of powders by means of DSC.

scholarly journals A STUDY OF PARAMETERS RELATED TO ANALYSIS OF TRANSITION TEMPERATURES AND ENTHALPIES OF POLYPROPYLENE BY DIFFERENTIAL SCANNING CALORIMETRY (DSC)

2002 ◽  
Vol 10 (11) ◽  
pp. 73-78
Author(s):  
Carlos R. Wolf ◽  
Emir Grave
Keyword(s):  
Differential Scanning Calorimetry ◽  
Material Characterization ◽  
Transition Temperatures ◽  
Nitrogen Flow ◽  
Thermoplastic Polymer ◽  
Scanning Calorimetry ◽  
Know How ◽  
Heating And Cooling ◽  
Polypropylene Material ◽  
Dsc Method

Polypropylene is a thermoplastic polymer, widely employed by converter industries to produce different plastic objects. In order to control and optimize the final properties of the polypropylene material, the evaluation of transition temperatures and enthalpies by Differential Scanning Calorimetry (DSC) has a very important role. Therefore, it is fundamental to know how the analytical conditions influence the results. In this study heating and cooling rates, 10°C/min and 20°C/min, and two different rates of nitrogen flow, 20mL/min and 50mL/min were investigated. It was concluded that thermal properties are influenced by rates of heating and rates of nitrogen flow. The best precision was obtained with the low heating rate, 10°C/min, and high flow rate, 50mL/min. These conditions are being used with the DSC method for polyolefin quality control and material characterization.

Phase Transitions and Thermal Expansion of 10mol%Sc2O3-1mol% CeO2-ZrO2 Ceramics

2007 ◽  
Author(s):  
Sergey Yarmolenko ◽  
Devendra Ray ◽  
Devdas Pai ◽  
Jag Sankar
Keyword(s):  
Thermal Expansion ◽  
Phase Transitions ◽  
Grain Structure ◽  
Slow Phase ◽  
Cubic Phase ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Operational Conditions ◽  
Β Phase

Phase transitions and CTE of 10mol%Sc2O3-1mol%CeO2-ZrO2 ceramics sintered from two commercial powders produced by Praxair Surface Technologies, USA and DKKK, Japan are studied. Morphology of powders and grain structure of ceramics were studied by SEM and AFM. Ceramics produced from Praxair powder exist in cubic phase while DKKK-based ceramics exhibit slow phase transformation from cubic to rhombohedral (β) phase at temperatures 350–400°C. c-β Phase transition temperature is 440°C obtained by high temperature x-ray diffractometry (HTXRD) and differential scanning calorimetry. Coefficients of thermal expansion of cubic and β-phases were calculated from temperature dependence of lattice parameters obtained by HTXRD in the temperature range of 25–800°C. These results can be further used for the optimal design of SOFC layered structures as well as for determination of their reliability and durability under operational conditions.

scholarly journals Analysis of Nucleation and Glass Formation by Chip Calorimetry

2021 ◽  
Vol 11 (16) ◽  
pp. 7652
Author(s):  
Meng Gao ◽  
Chengrong Cao ◽  
John H. Perepezko
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystal Nucleation ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
Heating And Cooling ◽  
Chip Calorimetry ◽  
In Situ Formation ◽  
Materials Behavior

The advent of chip calorimetry has enabled an unprecedented extension of the capability of differential scanning calorimetry to explore new domains of materials behavior. In this paper, we highlight some of our recent work: the application of heating and cooling rates above 104 K/s allows for the clear determination of the glass transition temperature, Tg, in systems where Tg and the onset temperature for crystallization, Tx, overlap; the evaluation of the delay time for crystal nucleation; the discovery of new polyamorphous materials; and the in-situ formation of glass in liquid crystals. From these application examples, it is evident that chip calorimetry has the potential to reveal new reaction and transformation behavior and to develop a new understanding.

scholarly journals Phase Transitions and Molecular Reorientations in Bilayered n-Heptadecylammonium Chloride

1998 ◽  
Vol 51 (3) ◽  
pp. 557 ◽  
Author(s):  
E. C. Reynhardt
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Scanning Calorimetry ◽  
Spin Lattice ◽  
Heating And Cooling ◽  
Α Phase ◽  
Monium Chloride

An investigation of phase transitions and molecular motions in polycrystalline n-heptadecylam- monium chloride (C17H35NH3Cl), employing differential scanning calorimetry, x-ray powder diffraction and nuclear magnetic resonance techniques, is reported. This compound can occur in two virgin polymorphs at room temperature, one interdigitated and one noninterdigitated. The temperature at which crystallisation occurs determines the polymorph that forms. If these polymorphs are heated transitions to noninterdigitated γ, β and α phases occur. Cooling to room temperature shows the same phase transitions, but the virgin phase is not formed. Instead, a noninterdigitated .epsi; phase is formed. Defect motions of chain-ends play a significant role in the spin-lattice relaxation rates in all the phases. In the α phase a degree of chain melting is present. The molecular dynamics of chains differs during heating and cooling cycles in the .epsi; phase. If the temperature is kept constant during a heating cycle in this phase, fourfold motions of chains are frozen over a period of several hours, but the sample remains noninterdigitated. It seems that the interdigitation process is hampered by the population of defect orientations of chain-ends. The methyl group executes classical threefold reorientations and the NH3 group jumps in an asymmetric threefold potential well.

Migration of model contaminants (ethylene glycol, DEHA and DEHP) from PET bottles into Iranian yogurt drink

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Mehdi Farhoodi ◽  
Zahra Emam-Djomeh ◽  
Mohammad Reza Ehsani ◽  
Abdolrasul Oromiehie
Keyword(s):  
Acetic Acid ◽  
Ethylene Glycol ◽  
Storage Temperature ◽  
Scanning Calorimetry ◽  
Pet Bottles ◽  
Dsc Method ◽  
Yogurt Drink ◽  
Ethylhexyl Phthalate ◽  
Migration Limit

AbstractThe migration of di-(2-ethylhexyl) adipate (DEHA), di-(2-ethylhexyl) phthalate (DEHP) and ethylene glycol from PET bottles into the Iranian yogurt drink was studied. According to European Commission regulations acetic acid (3% w/v) was chosen as stimulant. The acetic acid samples were stored at 4, 25 and 45 °C for four months and analyzed periodically by gas chromatography. Differential scanning calorimetry (DSC) was used to investigate if contact with the food stimulant could affect the PET material. It was concluded that the storage temperature had a great effect on the migration of DEHP, DEHA and ethylene glycol. Also increasing storage time resulted in higher concentrations of migrating substances. The concentrations of migrating substances did not exceed their specific migration limit (EEC regulations). Determination of glass transition (Tg) and crystallinity of PET bottles using DSC method showed that the variations in the migration rate of selected contaminants during the time did not relate to the change of PET material in contact with 3% acetic acid.

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