Synthesis, Processing and Phase Evolution of TiN/TiB2 Composites From Polymeric Precursors

1992 ◽  
Vol 286 ◽  
Author(s):  
M. Nowakowski ◽  
K. Su ◽  
L. Sneddon ◽  
D. Bonnell
Keyword(s):  
Phase Evolution ◽  
High Yield ◽  
Microstructural Development ◽  
Synthetic Route ◽  
Polymeric Precursors

ABSTRACTA high yield synthetic route to TiN/TiB2 nanocomposites based upon polymeric precursors has been developed. The phase evolution and microstructural development have been characterized and related to preliminary measurements of properties, i.e. hardness. The observations indicate the existence of TiN-TiB2, TiN-BN, and TiB2-BN subsolidus compatibilities.

scholarly journals A Synthetic Route to Quaternary Pyridinium Salt-Functionalized Silsesquioxanes

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Nataliya Kostenko ◽  
Jochen Gottfriedsen ◽  
Liane Hilfert ◽  
Frank T. Edelmann
Keyword(s):  
Pyridinium Salt ◽  
High Yield ◽  
Synthetic Route ◽  
Alkylation Reactions ◽  
Partial Success

A synthetic route to potentially biocidal silsesquioxanes functionalized by quaternary pyridinium functionalities has been developed.N-Alkylation reactions of the precursor compounds 4-(2-(trimethoxysilyl)ethyl)-pyridine (5) and 4-(2-trichloro-silylethyl)pyridine (6) with iodomethane,n-hexylbromide, andn-hexadecylbromide cleanly afforded the correspondingN-alkylpyridinium salts (7–10). The synthesis of a 4-(2-ethyl)pyridine POSS derivative (2) was achieved by capping of the silsesquioxane trisilanol Cy7Si7O9(OH)3(1) via two different preparative routes. Attempts to use compound2as precursor for quaternary pyridinium salt-functionalized POSS derivatives were met with only partial success. Only the reaction with iodomethane cleanly afforded the newN-methylpyridinium salt12in high yield, whereasn-hexylbromide andn-hexadecylbromide failed to react with2even under forcing conditions.

Microstructure and phase evolution of SrTiO3 thin films on Si prepared by the use of polymeric precursors

1997 ◽  
Vol 31 (3-6) ◽  
pp. 173-178 ◽  
Author(s):  
S.M. Zanetti ◽  
E. Longo ◽  
J.A. Varela ◽  
E.R. Leite
Keyword(s):  
Thin Films ◽  
Phase Evolution ◽  
Polymeric Precursors

scholarly journals Full N,N-Methylation of 4,4′-Methylenedianiline with Dimethyl Carbonate: A Feasible Access to 4,4′-Methylene bis(N,N-Dimethylaniline)

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Zegang Qiu ◽  
Kunjie Wang ◽  
Zhiqin Li ◽  
Tao Li ◽  
Jinhao Bai ◽  
...  
Keyword(s):  
Zinc Acetate ◽  
Dimethyl Carbonate ◽  
Reaction Pathway ◽  
Major Product ◽  
High Yield ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
High Yields ◽  
By Products

The full N,N-methylation of 4,4′-methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated. The yield of the major product 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) reached as high as 97% over NaY catalyst at 190°C for 6 h. The catalyst could be used for two more times with acceptable MBDMA yields higher than 90%. The main by-products were identified as three N-methylated derivatives. Surprisingly, the formation of the N-methoxycarbonylation product was extremely restrained, which could be produced in high yields of 98% on zinc acetate catalyst. Furthermore, the reaction pathway to the major product MBDMA was proposed. Finally, a feasible synthetic route of 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) was established, featuring a high yield, mild reaction conditions, and simple operations.

scholarly journals Influence of molybdenum content on the microstructure of spark plasma sintered titanium alloys

2021 ◽  
Vol 1 (1) ◽  
pp. 41-47
Author(s):  
M. Saravana Kumar ◽  
S. Rashia Begum ◽  
M. Vasumathi ◽  
Chinh Chien Nguyen ◽  
Quyet Van Le
Keyword(s):  
Relative Density ◽  
Phase Evolution ◽  
Microstructural Development ◽  
Sintered Titanium ◽  
Sintering Process ◽  
Plasma Sintering ◽  
The Matrix ◽  
Molybdenum Addition ◽  
Spark Plasma ◽  
Mo Content

Five titanium-based alloys containing 4, 8, 12, 16, and 20 wt% molybdenum additive were fabricated by spark plasma sintering process at 1200 ˚C. The samples were scrutinized in terms of relative density, phase evolution, and microstructural development. The relative density reached 99.9% with the molybdenum addition up to 16 wt% but slightly dropped in the sample with 20 wt% additive. In the specimens with 4 wt% Mo, molybdenum solved completely in the matrix and three different phase morphologies were observed, namely continuous α-Ti, laminar α-Ti, and very thin laminar β-Ti. With increasing Mo content to 20 wt%, widespread single β-Ti appeared alongside remained Mo and α-Ti. Ductile fracture mode was dominant in the samples with low Mo contents whilst it changed to brittle in the specimens with higher content of molybdenum.

scholarly journals Effect of lead content on phase evolution and microstructural development in Ag-clad Bi-2223 composite conductors

1997 ◽  
Author(s):  
N.N. Merchant ◽  
V.A. Maroni ◽  
A.K. Fischer ◽  
S.E. Dorris ◽  
W. Zhong ◽  
...  
Keyword(s):  
Phase Evolution ◽  
Lead Content ◽  
Microstructural Development ◽  
Composite Conductors

Facile Synthetic Route for Direct Access of Perylenediimide Single Crystals in High Yield through In Situ Crystallization

2020 ◽  
Vol 5 (6) ◽  
pp. 2070-2074
Author(s):  
Jayaraman Pitchaimani ◽  
Anu Kundu ◽  
Savarimuthu Philip Anthony ◽  
Dohyun Moon ◽  
Vedichi Madhu
Keyword(s):  
Single Crystals ◽  
Direct Access ◽  
High Yield ◽  
Synthetic Route ◽  
In Situ Crystallization

Microstructural development in solution-derived PZT thin films

1994 ◽  
Vol 52 ◽  
pp. 578-579
Author(s):  
T. J. Headley ◽  
B. A. Tuttle ◽  
J. A. Voigt ◽  
J. R. Michael
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Capital Investment ◽  
Perovskite Phase ◽  
Amorphous Film ◽  
Phase Evolution ◽  
Lead Zirconate ◽  
Solution Chemistry ◽  
Microstructural Development ◽  
Pzt Thin Films

Lead zirconate titanate (PZT) thin films are of technological interest for a variety of electronic and optical applications such as nonvolatile memories, decoupling capacitors, infrared detectors, and optical storage media. Fabrication of PZT films by solution deposition techniques is attractive because of uniform, stoichiometric control at the molecular level, ease of processing, and both low capital investment and total cost. Control of phase evolution, microstructure, crystallite size and orientation, and ferroelectric domain assemblage during processing is essential to optimize electrical and/or optical properties of the films. Factors which play a major role in controlling these parameters are details of the solution chemistry and mixing, thermal processing, Pb stoichiometry, Zr/Ti ratio, and substrate characteristics. Electron microscopy techniques have been used extensively to correlate microstructural features with film processing parameters as will be emphasized in this presentation.As annealing temperature is increased, phase evolution in PZT thin films typically proceeds from amorphous to pyrochlore to the ferroelectric perovskite phase. Fine-grained pyrochlore crystallizes from the amorphous film at low annealing temperatures and also precedes crystallization of the perovskite phase at higher temperatures. There is evidence that the Zr/Ti stoichiometry influences the microstructure of the amorphous-to-pyrochlore transformation.

scholarly journals Synthesis and Intramolecular Energy- and Electron-Transfer of 3D-Conformeric Tris(fluorenyl-[60]fullerenylfluorene) Derivatives

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3337
Author(s):  
He Yin ◽  
Min Wang ◽  
Loon-Seng Tan ◽  
Long Y. Chiang
Keyword(s):  
Electron Transfer ◽  
Direct Contact ◽  
Photophysical Properties ◽  
Molecular Packing ◽  
The Self ◽  
High Yield ◽  
Synthetic Route ◽  
Quenching Effect ◽  
Shape Structure ◽  
Energy And Electron Transfer

New 3D conformers were synthesized to show a nanomolecular configuration with geometrically branched 2-diphenylaminofluorene (DPAF-C2M) chromophores using a symmetrical 1,3,5-triaminobenzene ring as the center core for the connection of three fused DPAF-C2M moieties. The design led to a class of cis-cup-tris[(DPAF-C2M)-C60(>DPAF-C9)] 3D conformers with three bisadduct-analogous <C60> cages per nanomolecule facing at the same side of the geometrical molecular cis-cup-shape structure. A sequential synthetic route was described to afford this 3D configurated conformer in a high yield with various spectroscopic characterizations. In principle, a nanostructure with a non-coplanar 3D configuration in design should minimize the direct contact or π-stacking of fluorene rings with each other during molecular packing to the formation of fullerosome array. It may also prevent the self-quenching effect of its photoexcited states in solids. Photophysical properties of this cis-cup-conformer were also investigated.

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