Production of Al–Ti–C grain refiner alloys by reactive synthesis of elemental powders: Part I. Reactive synthesis and characterization of alloys

2000 ◽  
Vol 15 (12) ◽  
pp. 2620-2627 ◽  
Author(s):  
H. J. Brinkman ◽  
F. Zupanič ◽  
J. Duszczyk ◽  
L. Katgerman

The first part of this article reports on the reactive synthesis and characterization of Al–Ti–C alloys intended as master alloys for aluminum grain refining. The alloys were produced from elemental powders by the thermal explosion mode and analyzed with x-ray diffraction, scanning electron microscopy, and differential scanning calorimetry. Parameters were the titanium concentration (15 and 30 wt%) and the Ti/C ratio (9/1, 20/1, and 120/1) in the reactant powder mixture and the cooling rate after the reactive synthesis (1 and 120 °C/min). Full conversion of titanium and carbon into Al3Ti and TiC was achieved for the 30 wt% Ti mixtures but not for the 15 wt% Ti mixtures where the reaction was not exothermic enough. The Ti/C ratio did not affect the phase composition after reactive synthesis in the 30 wt% Ti alloys and could be used to tailor the microstructure of the alloy. The formation of Al4C3 was suppressed with a high cooling rate after the exothermic formation reactions.

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5552
Author(s):  
Ryota Kudo ◽  
Masahiro Sonobe ◽  
Yoshiaki Chino ◽  
Yu Kitazawa ◽  
Mutsumi Kimura

The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid.


2016 ◽  
Vol 71 (12) ◽  
pp. 1199-1209
Author(s):  
Vera A. Hartdegen ◽  
Maximilian S. Hofmayer ◽  
Konstantin Karaghiosoff ◽  
Thomas M. Klapötke

AbstractOn the basis of 1,2-bis(5-tetrazolo)ethane (BTE) the corresponding twofold vinyl and allyl N-substituted derivatives were synthesized using 1,2-dibromoethane and allyl bromide, respectively. The compounds were obtained as two different constitutional isomers. Both species were analyzed using NMR and IR spectroscopy, elemental analysis, as well as mass spectrometry. In the case of the diallyl bistetrazoles, the two isomers were characterized using 2D NMR spectroscopy. The synthesis of the divinyl compounds gave crystals of the 2,2′-N-substituted isomer, which were analyzed by single-crystal X-ray diffraction. The thermal stability of the compounds was determined using differential scanning calorimetry (DSC) and gave decomposition temperatures around 190°C and 230°C. For the investigation of the inherent energetic potential, sensitivities toward physical stimuli and detonation parameters were determined. The compounds turned out to be insensitive toward friction and impact and possess moderate energetic properties.


1999 ◽  
Vol 14 (5) ◽  
pp. 1805-1813 ◽  
Author(s):  
Florence Fusalba ◽  
Daniel Bélanger

A novel polyaniline-molybdenum trisulfide composite has been prepared by chemical polymerization from an acidic (1 M HCl) aqueous solution containing aniline and ammonium tetrathiomolybdate. The presence of molybdenum trisulfide in the polyaniline matrix induces morphological change to the polymer as evidenced by scanning electron micrographs. X-ray diffraction and differential scanning calorimetry indicate that polyaniline-molybdenum trisulfide is slightly less crystalline than polyaniline-HCl. X-ray photoelectron spectroscopy (XPS) and elemental analysis have been used to confirm the presence of molybdenum trisulfide in the polymer matrix. The XPS data also confirm that molybdenum trisulfide and tetrathiomolybdate anions are present with polyaniline to form a new inorganic-organic composite.


2009 ◽  
Vol 67 ◽  
pp. 227-232 ◽  
Author(s):  
Gurpreet Singh ◽  
Amrish Panwar ◽  
Anjan Sil ◽  
Sudipto Ghosh

Nanocrystalline LiMn2O4 powder was synthesized by sol-gel method using citric acid as a chelating agent. The powders were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Differential scanning calorimetry (DSC), Differential thermal analysis (DTA), Impedance spectroscopy (IS) and Electrochemical measurements. The powder particles having slight agglomeration characteristics were found to have prismatic morphology and a wider size distribution from 50 nm to 200 nm, which provides good packing density of the material. The electrical conductivity of the powder at room temperature is in the order of ~10-5 S/cm. The structural stability of LiMn2O4 cubic spinel over the temperature range of battery operation was assessed. Electrochemical performance of the material shows a discharge capacity of ~130 mAh/gm.


e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Cemil Alkan ◽  
Leyla Aras ◽  
Güngör Gündüz

Abstract A novel type of phthalocyanine polymer, 1,4-diazophenylene-bridged Cuphthalocyanine, was prepared from the diazonium salt of diaminobenzene and Cu(II) 1,8,15,22-tetraaminophthalocyanine. The polymer is partially soluble in tetrahydrofuran, dichloromethane, and dimethylformamide. Characterization of the polymer was performed by IR and UV-visible spectroscopy, X-ray diffraction, ash analysis, viscometry, differential scanning calorimetry and thermogravimetric analysis. The molecular weight of the soluble part of the polymer was determined by ebullioscopy. Electrical conductivity of the polymer and its doped samples were determined by the 4-probe technique. It was found that the electrical conductivity increased up to 10-4 S/cm after doping. The redox behaviour of the polymer was investigated utilizing cyclic voltammetry.


e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaowen Cui ◽  
Deyue Yan ◽  
Dan Xiao

Abstract Linear polyamides with high aliphatic content were prepared through step-heating melt polycondensation of tridecanedioic acid with various diamines. The synthesized polyamides were characterized comprehensively by means of IR, NMR and Raman spectroscopy. In addition, thermogravimetry, differential scanning calorimetry and dynamic mechanical analysis were used to investigate thermal properties of the obtained polyamides. It was found that melting and crystallization temperatures decrease as the aliphatic content increases. X-ray diffraction was applied to determine the crystal structures of the polyamides.


Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 377
Author(s):  
Kyosuke Isoda ◽  
Keigo Shimooka

In this article, we report on the synthesis and characterization of crown-ether appended hexaazatrinaphthylene derivatives with two alkoxy chains. The complexation of a derivative having shorter alkoxy chains with metal ions, such as NaI and KI, prompts remarkable changes in the electronic properties of sold states, because of changing intermolecular interactions. Polarized optical microscopic observation, X-ray diffraction pattern measurement and differential scanning calorimetry reveal that a compound with longer alkoxy chains self-assembles into the formation of the columnar liquid-crystalline phase. Moreover, the addition of benzenesulphonic acid influences the self-assembled liquid-crystalline structures, as well as the electronic properties. The complexation of the derivative having longer alkoxy chains with benzenesulphonic acid induces a larger dipole moment, compared to that before complexation, thereby leading to the enhancement of intermolecular interaction, such as dipole-dipole interaction. Also, peaks in UV-vis absorption and fluorescent spectra show a dramatically bathochromic shift, due to their intermolecular interaction, such as the π-π interaction.


2011 ◽  
Vol 311-313 ◽  
pp. 2075-2083
Author(s):  
Halidan Mamat

A novel cellulose-based oil absorbent crosslinked cellulose-dibutyl sebacate copolymers was prepared by the graft crosslinking polymerization of in situ synthesized dibutyl sebacate and cotton cellulose using potassium persulfate as an initiator. The copolymers were characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetry, differential scanning calorimetry, etc. The effects of reaction conditions, such as, ratio of reaction regents, reaction temperature, reaction time, etc, on the efficiency of oil absorbency were examined. The optimized reaction conditions for the synthesis of crosslinked cellulose-dibutyl sebacate copolymers were: m(cotton pulp):m(K2S2O8 initiator):m(dibutyl sebacate) = 1 0.025 2.0(W/W),75°C,and 5-6 h. The resulting crosslinked cellulose-dibutyl sebacate copolymers were floppy and exhibited excellent oil absorbency efficiency.


2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.


2019 ◽  
Vol 9 (01) ◽  
pp. 21-26
Author(s):  
Arif Budiman ◽  
Ayu Apriliani ◽  
Tazyinul Qoriah ◽  
Sandra Megantara

Purpose: To develop glibenclamide-nicotinamide cocrystals with the solvent evaporation method and evaluate their solubility and dissolution properties. Methods: Cocrystals of glibenclamide-nicotinamide (1:2) were prepared with the solvent evaporation method. The prediction of interactive cocrystals was observed using in silico method. The solubility and dissolution were performed as evaluation of cocrystals. The cocrystals also were characterized by differential scanning calorimetry (DSC), infrared spectrophotometry, and powder X-ray diffraction (PXRD). Result: The solubility and dissolution profile of glibenclamide-nicotinamide cocrystal (1:2) increased significantly compared to pure glibenclamide as well as its physical mixture. Characterization of cocrystal glibenclamide-nicotinamide (1:2) including infrared Fourier transform, DSC, and PXRD, indicated the formation of a new solid crystal phase differing from glibenclamide and nicotinamide. Conclusion: The confirmation of cocrystal glibenclamide-nicotinamide (1:2) indicated the formation of new solid crystalline phases that differ from pure glibenclamide and its physical mixture


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