scholarly journals RHEOLOGICAL PROPERTIES AND THERMAL STABILITY OF CAST COMPOSITIONS BASED ON POLYPHENYLENESULPHIDES

Author(s):  
A. B. Baranov ◽  
I. N. Tsapenko ◽  
A. V. Petrogradsky ◽  
I. D. Simonov-Emelyanov ◽  
N. L. Shembel

The rheological properties of polysulfide (PPS) melts and composite materials based on them were investigated in a wide range of temperatures and concentrations of fillers of different nature. It was established that the introduction of rheological additives into dispersed and hybrid-filled composite materials allows significantly reducing the viscosity and improving the processability of the compositions. Introduction of heat-stabilizing additives into PPS allows expanding the temperature interval of processing the composite materials based on PFC from 320 to 340°С. Complete thermal stability curves for the PPS compositions in a wide temperature range were obtained.

2020 ◽  
Vol 23 (04) ◽  
pp. 361-365
Author(s):  
M.K. Bakhadyrkhanov ◽  
◽  
B.K. Ismaylov ◽  
S.A. Tachilin ◽  
K.A. Ismailov ◽  
...  

The results of this study show that creation of clusters from impurity nickel atoms almost completely suppresses generation of thermal donors within the temperature range 450 to 1200 °C. The composition of these clusters was determined using the technique of energy dispersive X-ray spectroscopy, which revealed that the typical cluster consists of silicon atoms (65%), nickel atoms (15%) and oxygen atoms (19%). Based on the experimental results, the authors have suggested that the nickel atoms intensively perform the role of getter for oxygen atoms in the course of clusterization. It was shown that the additional doping of silicon with nickel at T = 1100…1200 °C enables to ensure a sufficiently high thermal stability of its electrical parameters within a wide temperature range.


Author(s):  
Akila C. Thenuwara ◽  
Pralav P. Shetty ◽  
Neha Kondekar ◽  
Chuanlong Wang ◽  
Weiyang Li ◽  
...  

A new dual-salt liquid electrolyte is developed that enables the reversible operation of high-energy sodium-metal-based batteries over a wide range of temperatures down to −50 °C.


2020 ◽  
Vol 40 (9) ◽  
pp. 727-735
Author(s):  
Rudinei Fiorio ◽  
Chaitanya Danda ◽  
João Maia

AbstractIn this study, thermoplastic polyurethanes (TPUs) containing trisilanol isooctyl polyhedral oligomeric silsesquioxane (POSS), a reactive nanofiller, were synthesized and characterized rheologically and morphologically, and the effects of POSS content on the melt thermal stability of the TPUs are investigated. Samples containing 0, 0.23, 0.57, 1.14, and 2.23% (w/w) POSS were synthesized by reactive extrusion and characterized by Fourier transform infrared spectroscopy (FTIR), oscillatory and extensional rheometry, atomic force microscopy (AFM), and small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). The rheological properties of molten TPU are time-dependent and the melt thermal stability of the TPU is maximal at 1.14% of POSS. The addition of 0.23 and 0.57% POSS promotes strain-hardening at low extensional strain rates (0.01 and 0.10 s−1), not affecting the extensional characteristics at higher strain rates. The addition of increasing amounts of POSS leads to the formation of POSS-rich clusters well dispersed in the TPU matrix. SAXS and WAXS results show that the POSS domains are amorphous and that POSS does not modify the crystalline structure of TPU. Therefore, this work indicates that synthesizing TPU in the presence of trisilanol isooctyl POSS can increase the melt thermal stability of the polymer, facilitating its processing.


Author(s):  
Peter J. Wyllie

SummaryExperimental data in the system CaO-MgO-FeO-SiO2 suggest that there may be a plateau on the liquidus and solidus of the multicomponent system basalt-peridotite. If this is so, fusion of peridotite would produce only basaltie magmas over a wide temperature range; when the temperature reached a value such that the liquid crossed the threshold of the plateau, there would be a rapid increase in the amount of fusion for small temperature increases, with the formation of picritic magmas; basaltic magmas containing suspended forsteritic olivine crystals could dissolve them if the temperature rose slightly above that of the plateau threshold; a high proportion of a picritic magma would crystallize in a small temperature interval, with the precipitation of forsteritic olivine that was only slightly zoned. These possibilities are compared with current theories, and it is concluded that several petrological axioms may require critical re-examination. An experimental procedure is outlined to determine the shape of the liquidus and solidus in the basalt-peridotite system.


2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
A. A. Lukin ◽  
E. I. Il'yashenko ◽  
A. T. Skjeltorp ◽  
G. Helgesen

The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡). The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,25)15(Fe0,71Co0,29)bal ⋅ Al0,9Cu0,1B8,5 (at. %) after optimal thermal treatment {1175 K (3,6–7,2 ks) with slow (12–16 ks) cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.


RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16183-16186 ◽  
Author(s):  
W. Xu ◽  
S. S. Yu ◽  
H. Zhang ◽  
H. B. Duan

A MOFs compound [NH2(CH3)2]2[Zn3(bpdc)4]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1′) possesses an ultra-low κ value of 1.80 (at 100 kHz) over a wide temperature range and high thermal stability.


2013 ◽  
Vol 113 (17) ◽  
pp. 17A310 ◽  
Author(s):  
Jia Wang ◽  
Zhi Wang ◽  
Yun-yun Jia ◽  
Rui-min Shi ◽  
Zhuan-ping Wen ◽  
...  

2016 ◽  
Vol 9 ◽  
pp. 82-89
Author(s):  
Maya Radune ◽  
Michael Zinigrad ◽  
David Fuks ◽  
S. Hayun ◽  
Nachum Frage

Supersaturated titanium-aluminum nitride (Ti1-xAlxN) is a very attractive material for a wide range of applications due to its high oxidation and wear resistance accompanied by high strength, hardness, thermal conductivity and thermal shock resistance. Currently, its applications are limited to coatings obtained by physical or chemical deposition. Bulk materials based on Ti1-xAlxN may be fabricated by powder metallurgy approach using powders synthesized by high-energy ball milling (HEBM), which composition corresponds to supersaturated Ti1-xAlxN solid solution. In the present study, thermal stability of the supersaturated Ti1-xAlxN solid solution was investigated. According to the quasi-binary TiN-AlN phase diagram, constructed using density functional theory (DFT) analysis, the concentration ranges, where decomposition takes place through spinodal decomposition or through nucleation and growth, were determined. Experimental study on thermal stability of solid Ti1-xAlxN solution powder was conducted by means of differential scanning calorimetry (DSC), Brunauer-Emmited-Teller (BET) and XRD. The results indicated that spinodal decomposition of Ti1-xAlxN starts at 800°C, while at temperature higher than 1300°C regular decomposition (nucleation and growth) is occur.


2011 ◽  
Vol 685 ◽  
pp. 340-344 ◽  
Author(s):  
Tung Wai Leo Ngai ◽  
Chang Xu Hu ◽  
Wei Zheng ◽  
Heng Xie ◽  
Yuan Yuan Li

Ti, SiC and their composite materials have been widely used as high temperature structural material. The knowledge of interfacial stability between SiC and Ti is vital in high temperature applications. In this study, SiC/Ti diffusion couples were prepared to investigate the interfacial reactions between SiC and Ti at 1273 K. Phase forming sequence, microstructure and thermal stability of SiC/Ti interface were studied. It was indicated that after annealed at 1273 K for 10 days, 4 reaction layers were formed at the SiC/Ti interface. The diffusion path between SiC and Ti is SiC/Ti3SiC2/Ti5Si3/Ti5Si3+TiC/Ti3Si/Ti. As the annealing time prolong, the thicknesses of these reaction layers increased.


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