Morphology of Sintered Cr-Mo Porous Materials

2015 ◽  
Vol 825-826 ◽  
pp. 838-843
Author(s):  
Moritz Boehm ◽  
Thomas Schmoelzer ◽  
Reinhard Simon ◽  
Christian Gierl-Mayer
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Linear Expansion ◽  
Solid Phase ◽  
Phase Region ◽  
Miscibility Gap ◽  
Liquidus Boundary ◽  
Different Temperatures ◽  
Scanning Electron

Chromium and molybdenum exhibit continuous solubility in the solid phase region at temperatures of 908°C and above [1]. At lower temperatures, the system exhibits a miscibility gap. Furthermore a congruent minimum in the liquidus boundary exists at 1854°C. Chromium and molybdenum powders with different particle morphologies were mixed and porous green parts were produced by pressing. Sintering experiments were performed at different temperatures and for different chromium to molybdenum ratios. To investigate the evolution of the microstructure, sintering was interrupted at different temperatures and points in time. The microstructure and morphology of the sintered parts was investigated by scanning electron microscopy as well as light optical microscopy. It was found that during sintering, a Cr-Mo solid solution is formed. Depending on the molybdenum content, this induces either shrinking or swelling of the porous parts. Samples exhibited a linear expansion of up to 10% and final porosities of up to 65%.

Laser micromachining of Al2O3−TiC ceramics

1997 ◽  
Vol 12 (12) ◽  
pp. 3206-3209 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar ◽  
O. Conde ◽  
P. Freitas
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Laser Irradiation ◽  
Removal Rate ◽  
Stationary Regime ◽  
Strong Variation ◽  
Irradiation Process ◽  
Scanning Electron

Al2O3−34 wt.% TiC ceramics have been machined with a KrF (248 nm) excimer laser under normal atmosphere. In the initial steps of the irradiation process both the roughness and the removal rate present a strong variation with the number of pulses. After approximately 200 pulses the process reaches a stationary regime where the roughness and the removal rate become constant. Characterization of the machined areas by scanning electron microscopy showed that the variations in roughness and removal rate are related to the evolution of the surface topography of the samples. Also, as a consequence of laser irradiation, TiC and Al2O3 are partially transformed into TiO2, TiC0.7N0.3, and an Al–Ti solid solution.

Poly (vinylcaprolactam)-based Microgels to Improve Gloss Properties of Different Natural Fibres

2014 ◽  
Vol 18 (1) ◽  
pp. 50-63 ◽  
Author(s):  
A.G. Hassabo ◽  
S. Schachschal ◽  
C. Cheng ◽  
A. Pich ◽  
C. Popescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Itaconic Acid ◽  
Natural Fibres ◽  
Different Temperatures ◽  
Scanning Electron

Three different thermo-sensitive microgels obtained by the copolymerisation of vinylcaprolactam) (VCL) and various monomers (vinylimidazole(VIm), acetoacetoxyethyl methacrylate (AAEM) and itaconic acid(IA)) are used to coat different fibre surfaces. Two different pHs and two different temperatures, 25°C and 50°C respectively are chosen for the deposition of the microgels. The scanning electron microscopy of the treated fibre shows good distribution of the particles onto the fibres especially at increasing temperatures. The gloss index for the treated fibres has been measured, and showed that it may be controlled for all of the fibres with the treatment parameters (pH and temperature) and the microgel structure.

Synthesis of Ti3Si0.4Al0.8C1.8 Solid Solution

2008 ◽  
Vol 368-372 ◽  
pp. 995-997
Author(s):  
Cui Wei Li ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
Zhi Li Zhang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Scanning Electron

In this study, free Ti/Si/Al/C powder mixtures with molar ratio of 3:0.4:0.8:1.8 were heated in Argon with various schedules, in order to reveal the possibility for the synthesis of Ti3Si0.4Al0.8C1.8 solid solution powder. X-ray diffraction (XRD) was used for the evaluation of phase identities of the powder after different treatments. Scanning electron microscopy (SEM) was used to observe the morphology of the Ti3Si0.4Al0.8C1.8 solid solution. XRD results showed that predominantly single phase samples of Ti3Si0.4Al0.8C1.8 was prepared after heating at 1400oC for 5 min in Argon and the lattice parameters of Ti3Si0.4Al0.8C1.8 lay between those of Ti3SiC2 and Ti3AlC2.

Reaction Behavior of Phosphorus in CaO-SiO2-FeOx Low Basicity Slag

2011 ◽  
Vol 282-283 ◽  
pp. 129-132
Author(s):  
Chang Su ◽  
Jing Kun Yu ◽  
Ning Ning Lv
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Condensed Phase ◽  
Molten Slag ◽  
Heating Temperature ◽  
Holding Time ◽  
Reaction Behavior ◽  
X Ray ◽  
Scanning Electron

For investigating the reaction behavior of phosphorus in CaO–SiO2–FeOx low basicity slag, the CaO–SiO2–FeOx slag containing various amount of CaO particles was heated at 1623K and 1673K, respectively for 10 to 600s, and the products formed at the interface of the CaO particles and molten slag were observed by scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). The research results showed that the solid solution containing P2O5 increased with the increasing of the heating temperature, and the formation of condensed phase was promoted by increasing the holding time and the CaO solid proportion.

scholarly journals Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Halyna Klym ◽  
Ivan Karbovnyk ◽  
Andriy Luchechko ◽  
Yuriy Kostiv ◽  
Viktorija Pankratova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Grain Boundaries ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Scanning Electron

BaGa2O4 ceramics doped with Eu3+ ions (1, 3 and 4 mol.%) were obtained by solid-phase sintering. The phase composition and microstructural features of ceramics were investigated using X-ray diffraction and scanning electron microscopy in comparison with energy-dispersive methods. Here, it is shown that undoped and Eu3+-doped BaGa2O4 ceramics are characterized by a developed structure of grains, grain boundaries and pores. Additional phases are mainly localized near grain boundaries creating additional defects. The evolution of defect-related extended free volumes in BaGa2O4 ceramics due to the increase in the content of Eu3+ ions was studied using the positron annihilation lifetime spectroscopy technique. It is established that the increase in the number of Eu3+ ions in the basic BaGa2O4 matrix leads to the agglomeration of free-volume defects with their subsequent fragmentation. The presence of Eu3+ ions results in the expansion of nanosized pores and an increase in their number with their future fragmentation.

Effects of V2O5 on the synthesis of Ba2Ti9O20 powders

2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Eutectic Liquid ◽  
X Ray ◽  
Intermediate Phases ◽  
Phase Pure ◽  
Scanning Electron

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.

scholarly journals Joining of γ-TiAl Alloy to Ni-Based Superalloy Using Ag-Cu Sputtered Coated Ti Brazing Filler Foil

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 723 ◽  
Author(s):  
Sónia Simões ◽  
Carlos Tavares ◽  
Aníbal Guedes
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Tial Alloy ◽  
Energy Dispersive ◽  
X Ray ◽  
Base Materials ◽  
Intermetallic Particles ◽  
Scanning Electron

Joining γ-TiAl alloy to Ni-based superalloy Hastelloy using Ag-Cu sputtered coated Ti foil as brazing filler was investigated in this study. Brazing experiments were performed at 900, 950, and 980 °C with a dwelling stage of 10 min in vacuum. The microstructure and the chemical composition of the resulting interfaces were analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. Sound joints were produced after brazing at 980 °C, presenting a multilayered interface, consisting mainly of Ti-Al and Ti-Ni-Al intermetallics close to the γ-TiAl alloy, and of Ti-rich, Ti-Ni, and Cr-Ni-Mo rich phases near Hastelloy. The hardness of the interface, ranging from around 300 to 1100 HV0.01, is higher than both base materials, but no segregation of either Ag solid solution or coarse intermetallic particles was observed. Therefore, the developed brazing filler also avoids the need to perform post-brazing heat treatments that aim to eliminate detrimental extensive segregation of either soft phases or of hard and brittle compounds.

Microwave-Assisted Preparation of Cu2O Octahedral Microcrystals

2011 ◽  
Vol 284-286 ◽  
pp. 746-749
Author(s):  
Chong Hai Deng ◽  
Han Mei Hu ◽  
Ming Di Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Growth Mechanism ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Microwave Assisted ◽  
Morphology And Structure ◽  
Scanning Electron

In this paper, we reported a facile microwave-assisted green chemical route to prepare pure, uniform, and monodispersed Cu2O octahedron wrapped by the {111} faces by using glucose as a reducing agent. X-ray diffraction (XRD), energy dispersive X-ray spectrometry(EDX) and field emission scanning electron microscopy (FESEM) were used to characterize the as-synthesized products. It was found that the morphology and structure of Cu2O crystals were greatly affected by the concentration of NaOH. A solid-solution-solid growth mechanism was possibly proposed on the basis of the comparative experimental results.

Dispersive solid phase extraction of copper and lead from water and lichen samples with an activated carbon@Fe/Mn/O composite derived from sucrose-based activated carbon

2019 ◽  
Vol 11 (41) ◽  
pp. 5311-5319 ◽  
Author(s):  
Veysel Berkdemir ◽  
Şerife Tokalıoğlu ◽  
Süleyman Yıldız ◽  
Şaban Patat
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Activated Carbon ◽  
Zeta Potential ◽  
Solid Phase ◽  
Phase Extraction ◽  
Dispersive Solid Phase Extraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this study, an activated carbon@Fe/Mn/O composite was synthesized and characterized by X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface area and zeta potential measurements.

Sign in / Sign up

Export Citation Format

Share Document