New evidence for supported metals in the reaction of KC8 with metal chlorides

1992 ◽  
Vol 7 (2) ◽  
pp. 418-422 ◽  
Author(s):  
A. Messaoudi ◽  
F. Béguin
Keyword(s):  
Graphite Powder ◽  
Intercalation Compounds ◽  
X Ray Diffraction ◽  
Metal Chlorides ◽  
X Ray ◽  
Graphene Layers ◽  
Graphite Intercalation ◽  
The Matrix ◽  
New Evidence

The evolution of the reaction between the binary graphitide KC8 and CoCl2 dissolved in anhydrous tetrahydrofuran (THF) has been investigated by in situ x-ray diffraction (XRD). During the reaction and whatever the host graphite (powder or HOPG), the first stage graphite intercalation compounds K(THF)2.5C24 and K(THF)1.7C24 are first formed and then transformed into higher stages. Finally the matrix is exfoliated and the phases identified are graphite, metallic cobalt, and KCl. Analyses by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) clearly show that the products are mainly located at the edge planes of the graphite, indicating that the electronic exchange occurs at the edge of the graphene layers. It is now clear that graphite-cobalt intercalation compounds cannot be obtained by this method.

Fabrication of TiAl/Ti2AlC Composite by Reaction Hot Pressing

2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Electron Microscopy ◽  
Reaction Process ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Composite ◽  
The Matrix ◽  
Morphology Characteristics ◽  
Scanning Electron

TiAl/Ti2AlC in situ composite was successfully fabricated by hot-press-assisted reaction process from the mixture of Ti, Al and carbon black. The phase formation and transformation were investigated in detail by X-ray diffraction (XRD) and the morphology characteristics were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that when the mixed powders were hot pressed at 1300 °C for 1 h, full dense and highly pure TiAl/Ti2AlC composite was synthesized. The TiAl was the matrix phase and the in situ synthesized Ti2AlC was reinforcing phase. The reaction process was also discussed.

Graphite Intercalation Compounds with Trimethyltin Chloride

1984 ◽  
Vol 39 (6) ◽  
pp. 788-790 ◽  
Author(s):  
Robert Schlögl ◽  
Hanns-Peter Boehm
Keyword(s):  
Chemical Analysis ◽  
Uv Irradiation ◽  
Intercalation Compounds ◽  
X Ray Diffraction ◽  
Graphite Intercalation Compounds ◽  
X Ray ◽  
Graphite Intercalation ◽  
Anionic Species ◽  
Trimethyltin Chloride ◽  
Stage 1

AbstractIntercalation compounds of graphite with Sn(CH3)3Cl have been prepared by UV irradiation, in the presence of graphite, of solutions of Sn(CH3)3Cl, Sn(CH3)4, or of Sn(CH3)4 + SnCl4 in CCl4. Mixtures of stage 1, stage 2, and stage 3 compounds have been obtained. They were characterized by X-ray diffraction, 119Sn Mossbauer spectroscopy, and by chemical analysis. Apparently an oligomeric, anionic species is intercalated together with some solvent.

Binary and Ternary Alkali Graphite Intercalation Compounds: In-Situ X-Ray Study Of Elastic And Electrostatic Effects on Staging

1982 ◽  
Vol 20 ◽  
Author(s):  
M.E. Misenheimer ◽  
P. Chow ◽  
H. Zabel
Keyword(s):  
Interlayer Spacing ◽  
Intercalation Compounds ◽  
Concentration Region ◽  
Graphite Intercalation Compounds ◽  
X Ray ◽  
Small Defect ◽  
Graphite Intercalation ◽  
Spacing Variation ◽  
Elastic Distortion

ABSTRACTWe have studied stage transformations of binary potassium-graphite intercalation compounds by in-situ x-ray (00ℓ) scans. In the transition region of stages one and two, both stages coexist and all Bragg reflections exhibit resolution limited widths. The characteristics of the stage transformation are identical in intercalated HOPG and single crystals. This implies that the stage transformation is a direct process with no need of forming intermediate structures, favoring electrostatic interaction as the dominant stabilizer for pure stage donor compounds. We have also studied the elastic distortion due to potassium atoms substitutionally dissolved in rubidium intercalant layers. From the interlayer spacing variation we find a double force tensor Pzz = 0.36 eV for potassium defects in RbC8 in the small defect concentration region.

In Situ Structural Evolution of Steel-Based MMC by High Energy X-Ray Diffraction and Comparison with Micromechanical Approach

2013 ◽  
Vol 768-769 ◽  
pp. 313-320 ◽  
Author(s):  
Guillaume Geandier ◽  
Moukrane Dehmas ◽  
Mickael Mourot ◽  
Elisabeth Aeby-Gautier ◽  
Sabine Denis ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Coefficient Of Thermal Expansion ◽  
Hydrostatic Stress ◽  
Structural Evolution ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
The Matrix

In situ high energy X-ray diffraction synchrotron was used to provide direct analysis of the transformation sequences in steel-based matrix composite (MMC) reinforced with TiC particles. Evolution of the phase fractions of the matrix and TiC particles as well as the mean cell parameters of each phase were determined by Rietveld refinement from high energy X-ray diffraction (ID15B, ESRF, Grenoble, France). In addition, some peaks were further analysed in order to obtain the X-ray strain during the cooling step. Non-linear strain evolutions of each phase are evidenced, which are either associated with differences in the coefficient of thermal expansion (CTE) between matrix and TiC particle or to the occurrence of phase transformation. Micromechanical calculations were performed through the finite element method to estimate the stress state in each phase and outline the effects of differences in CTE and of volume change associated with the matrix phase transformation. The calculated results led to a final compressive hydrostatic stress in the TiC reinforcement and tensile hydrostatic stress in the matrix area around the TiC particles. Besides, the tendencies measured from in situ synchrotron diffraction (mean cell parameters) matched with the numerical estimates.

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