Thermal Properties and Crystallization Behavior of Co67Fe4Cr7Si8B14 Amorphous Alloy

2010 ◽  
Vol 297-301 ◽  
pp. 330-337
Author(s):  
M. Haddad-Sabzevar ◽  
S. Sahebian ◽  
Z. Jamili ◽  
S.A. Hasheminejad

In order to investigate the crystallization behavior of the Co67Fe4Cr7Si8B14 amorphous metallic alloy, ribbons of this alloy were prepared by planar flow melt spinning process (PFMS). Differential scanning calorimetery (DSC) and differential thermal analyzer (DTA) were used to analyze the thermal properties and crystallization behavior of the samples at three heating rates of 10, 20 and 30º C/min. The experimental data were fitted to the Avrami model to determine the crystallization behavior. The results showed that the crystallization exotherm became wider and shifted toward a higher temperature range as the heating rate increased. The Avrami analysis also showed that n is about 1, which is related to the same transformation mechanism at different heating rates. The Kissinger method was used to determine the activation energy for the first crystallization peaks. The measured value is approximately 332.67 kJ/g.

Seikei-Kakou ◽  
1989 ◽  
Vol 1 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Takeshi KIKUTANI ◽  
Yutaka KAWAHARA ◽  
Takayuki MATSUI ◽  
Akira TAKAKU ◽  
Jiro SHIMIZU

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Puli Nageswar Rao ◽  
G. K. Sabavath ◽  
S. N. Paul

AbstractIn Polyethylene terephthalate (PET) processing the raw materials are purified terephthalic acid (PTA), moderately purified terephthalic acid (MTA), monoehalene glycol (MEG). The processing of PTA is very difficult and costly. For reducing PTA percent we are using different percentages of MTA blend in PET processing. MTA affected the properties of polyester and melt spinning process. The properties such as elongation, tenacity, molecular chain length, b-color and IV, thermal properties, % carboxyl groups will change with MTA percentage. MTA percentage also affects fiber breakage percentage s, the melting point of PET. FTIR results show a change in chemical composition. Particle size, 4-CBA content of MTA affects the properties of the fiber.


2014 ◽  
Vol 36 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Bahareh Kalantari ◽  
Mohammad Reza Mohaddes Mojtahedi ◽  
Farhad Sharif ◽  
Ruhollah Semnani Rahbar

1970 ◽  
Vol 17 (1) ◽  
pp. 38-42
Author(s):  
Anna BIEDUNKIEWICZ ◽  
Pawel FIGIEL ◽  
Marta SABARA

The results of investigations on pyrolysis and oxidation of pure polyacrylonitrile (PAN) and its mixture with N,N-dimethylformamide (DMF) under non-isothermal conditions at linear change of samples temperature in time are presented. In each case process proceeded in different way. During pyrolysis of pure PAN the material containing mainly the product after PAN cyclization was obtained, while pyrolysis of PAN+DMF mixture gave the product after cyclization and stabilization. Under conditions of measurements, in both temperature ranges, series of gaseous products were formed.For the PAN-DMF system measurements at different samples heating rates were performed. The obtained results were in accordance with the kinetics of heterogeneous processes theory. The process rates in stages increased along with the temperature increase, and TG, DTG and HF function curves were shifted into higher temperature range. This means that the process of pyrolysis and oxidation of PAN in dry air can be carried out in a controlled way.http://dx.doi.org/10.5755/j01.ms.17.1.246


2015 ◽  
Vol 68 (6) ◽  
pp. 1125-1129 ◽  
Author(s):  
M. Swaroopa ◽  
L. Venu Gopal ◽  
T. Kishen Kumar Reddy ◽  
B. Majumdar

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Corrado Berti ◽  
Annamaria Celli ◽  
Paola Marchese ◽  
Elisabetta Marianucci ◽  
Giancarlo Barbiroli ◽  
...  

AbstractSome poly(alkylene dicarboxylate)s, derived from ethanediol or 1,4- butanediol and different diacids, have been synthesized and analyzed by DSC to determine the correlations existing between the thermal properties and the length of the aliphatic chain. The polymers show crystallization and melting temperatures and enthalpies which increase as the polymethylene segments lengthen, due to the formation of more stable crystals. The samples derived from ethanediol are peculiar; they show reorganization processes during the melting and the melting temperatures are notably higher with respect to those of the other polyesters. This behavior is discussed. Isothermal analysis highlights that poly(alkylene dicarboxylate)s are fast crystallizing polymers. The Avrami analysis suggests a crystallization mechanism characterized by heterogeneous nucleation and three dimensional growth; secondary crystallizations is present only in the samples characterized by short -(CH2)- sequences, due to the reorganization of less perfect crystalline forms. A comparative study between the crystallization rates as a function of the undercooling is reported.


2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Eric Devaux ◽  
Carole Aubry ◽  
Christine Campagne ◽  
Maryline Rochery

Polylactide (PLA) was mixed with 4 wt.% of carbon nanotubes (CNTs) to produce electrical conductive multifilament yarns by melt spinning process for humidity detection. Thanks to a variation of electrical conductivity, this flexible sensor could detect the moisture presence. The introduction of plasticizer was necessary to ensure higher fluidity and drawability of the blend during the spinning process. The plasticizer modifies the crystallinity and the mechanical properties of the yarns. The effectiveness of this sensor (PLA/4 wt.% CNTs fibres) sensitive to humidity, is optimal when the spinning conditions are adapted. In this way, the temperature and the rate of the drawing roll were reduced. The influence of these parameters on the crystallinity, the mechanical properties and the sensitivity of the yarns were studied. Once the appropriate spinning conditions found, one humidity sensitive yarn was processed and the repeatability and efficient reversibility of its sensitivity were highlighted.


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