scholarly journals Magnetite solubility and phase stability in alkaline media at elevated temperatures

1995 ◽  
Vol 24 (9) ◽  
pp. 837-877 ◽  
Author(s):  
S. E. Ziemniak ◽  
M. E. Jones ◽  
K. E. S. Combs
Keyword(s):  
Phase Stability ◽  
Elevated Temperatures ◽  
Alkaline Media

Solubility behavior of titanium(IV) oxide in alkaline media at elevated temperatures

1993 ◽  
Vol 22 (7) ◽  
pp. 601-623 ◽  
Author(s):  
S. E. Ziemniak ◽  
M. E. Jones ◽  
K. E. S. Combs
Keyword(s):  
Elevated Temperatures ◽  
Alkaline Media ◽  
Solubility Behavior

scholarly journals The effect of cobalt on morphology, structure, and ORR activity of electrospun carbon fibre mats in aqueous alkaline environments

2021 ◽  
Vol 12 ◽  
pp. 1173-1186
Author(s):  
Markus Gehring ◽  
Tobias Kutsch ◽  
Osmane Camara ◽  
Alexandre Merlen ◽  
Hermann Tempel ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Elevated Temperatures ◽  
Current Collector ◽  
Alkaline Media ◽  
Emission Spectrometry ◽  
Free Standing ◽  
X Ray ◽  
Turbostratic Carbon ◽  
Current Densities

An innovative approach for the design of air electrodes for metal–air batteries are free-standing scaffolds made of electrospun polyacrylonitrile fibres. In this study, cobalt-decorated fibres are prepared, and the influence of carbonisation temperature on the resulting particle decoration, as well as on fibre structure and morphology is discussed. Scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry are used for characterisation. The modified fibre system is compared to a benchmark system without cobalt additives. Cobalt is known to catalyse the formation of graphite in carbonaceous materials at elevated temperatures. As a result of cobalt migration in the material the resulting overall morphology is that of turbostratic carbon. Nitrogen removal and nitrogen-type distribution are enhanced by the cobalt additives. At lower carbonisation temperatures cobalt is distributed over the surface of the fibres, whereas at high carbonisation temperatures it forms particles with diameters up to 300 nm. Free-standing, current-collector-free electrodes assembled from carbonised cobalt-decorated fibre mats display promising performance for the oxygen reduction reaction in aqueous alkaline media. High current densities at an overpotential of 100 mV and low overpotentials at current densities of 333 μA·cm−2 were found for all electrodes made from cobalt-decorated fibre mats carbonised at temperatures between 800 and 1000 °C.

Phase Stability and High Temperature Tensile Properties of W doped gamma-TiAl

2000 ◽  
Vol 646 ◽  
Author(s):  
Keizo Hashimoto ◽  
Hirohiko Hirata ◽  
Youji Mizuhara
Keyword(s):  
High Temperature ◽  
Phase Stability ◽  
Ternary Phase ◽  
Elevated Temperatures ◽  
Ternary Phase Diagram ◽  
Arc Melting ◽  
Structural Applications ◽  
High Temperature Tensile ◽  
Promising Alloys ◽  
High Temperature Tensile Properties

ABSTRACTTungsten (W) doped γ-TiAl is one of promising alloys among many other proposed TiAl base alloys, for the purpose of structural applications at elevated temperatures. Ingots of W doped γ-TiAl were produced by plasma arc melting, followed by homogenizing heat treatment and isothermal forging to control their microstructures. The phase stability of W doped γ-TiAl has been studied quantitatively, using the specimens quenched from 1273 K. Equilibrium compositions of consisting phases were analyzed by means of EDS analysis in a TEM. An isothermal cross section of the Ti-Al-W ternary phase diagram at 1273K has been proposed based on the experimental observations. Small amounts of W addition (< 1at%) to Ti-48at%Al cause a phase shift from α2+γ to α2+β+γ, which suggests that W is the strongest β stabilizer among transition metals, such as Cr and Mo. Mechanical property measurements of W doped γ-TiAl show that the high temperature tensile strength has been improved by the W addition. Relationships between the microstructures and the mechanical properties of W doped γ-TiAl have been discussed.

scholarly journals Selective Suppression of {112} Anatase Facet by Fluorination for Enhanced TiO2 Particle Size and Phase Stability at Elevated Temperatures

2021 ◽  
Author(s):  
Emerson Cristofer Kohlrausch ◽  
Roberto dos Reis ◽  
Rhys Lodge ◽  
Isabel Vicente ◽  
Alexandre Brolo ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Stability ◽  
Elevated Temperatures ◽  
Rutile Phase ◽  
Tio2 Particle ◽  
Recombination Rates ◽  
Selective Suppression ◽  
Photocatalytic Applications

Generally, anatase is the most desirable TiO2 polymorphic phase for photovoltaic and photocatalytic applications due to its higher photoconductivity and lower recombination rates compared to rutile phase. However, in applications...

scholarly journals Phase stability and mechanical properties of wire + arc additively manufactured H13 tool steel at elevated temperatures

2021 ◽  
Vol 67 ◽  
pp. 80-94 ◽  
Author(s):  
A.N.M. Tanvir ◽  
Md. R.U. Ahsan ◽  
Gijeong Seo ◽  
Brian Bates ◽  
Chanho Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tool Steel ◽  
Phase Stability ◽  
Elevated Temperatures ◽  
H13 Tool Steel

Influence of Two-Step Sintering Variables on Phase Stability of Hydrothermally Prepared HAp Nano Powders

2007 ◽  
Vol 361-363 ◽  
pp. 91-94 ◽  
Author(s):  
In Young Ryu ◽  
Dae Joon Kim ◽  
Jung Suk Han ◽  
Myung Hyun Lee
Keyword(s):  
Heating Rate ◽  
Phase Stability ◽  
Initial Temperature ◽  
Elevated Temperatures ◽  
Powder Processing ◽  
Processing Condition ◽  
High Density ◽  
Final Temperature ◽  
Fine Microstructure ◽  
High Phase

Two-step sintering was performed to prepare hydroxyapatite (HAp) with a high density and a fine microstructure utilizing hydrothermally synthesized nano powders. Its effectiveness was dependent on starting chemicals for precursors of HAp, powder processing condition, initial temperature in the two-step sintering, heating rate to the initial temperature, and holding time at final temperature. HAp powder, hydrothermally treated after aging of precipitate of Ca(OH)2 and H3PO4 for 48 h, led to HAp having a high phase stability at elevated temperatures, a high density, and a fine microstructure after two-step sintering with heating rate of 10°C/min to 1275°C.

scholarly journals Solubility of Litharge (α-PbO) in Alkaline Media at Elevated Temperatures

2005 ◽  
Vol 34 (12) ◽  
pp. 1407-1428 ◽  
Author(s):  
S. E. Ziemniak ◽  
D. A. Palmer ◽  
P. Bénézeth ◽  
L. M. Anovitz
Keyword(s):  
Elevated Temperatures ◽  
Alkaline Media
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