The Thermal-Oxidation Behavior of Pristine and Doped Magnéli Phase Titanium Oxides

2021 ◽  
Author(s):  
Joseph English ◽  
David Wilkinson
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Behavior ◽  
Titanium Oxides ◽  
Magnéli Phase ◽  
Magneli Phase

Reduction in the Thermal Conductivity of Thermoelectric Titanium Oxide by Introduction of Planar Defects

2009 ◽  
Vol 1218 ◽  
Author(s):  
Shunta Harada ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Thermal Conductivity ◽  
Titanium Oxide ◽  
Hot Pressing ◽  
Oxygen Deficiency ◽  
Nominal Composition ◽  
Titanium Oxides ◽  
X Ray Diffraction ◽  
Planar Defects ◽  
Magnéli Phase ◽  
Magneli Phase

AbstractThermoelectric properties of a homologous series of Magnéli phase titanium oxides TinO2n-1 (n = 2, 3..) have been investigated. Dense polycrystalline specimens with nominal composition of TiO2-x (x = 0.10, 0.20) have been prepared by conventional hot-pressing. X-ray diffraction analysis has revealed that prepared specimens are slightly reduced during hot-pressing. Electrical conduction is of n-type for all prepared titanium oxides and electrical resistivity and absolute values of Seebeck coefficient decrease with increasing oxygen deficiency. The carrier concentration of Magnéli phase titanium oxide increases with increasing oxygen deficiency. Lattice thermal conductivity decreases with increasing oxygen deficiency by more than 60% at room temperature and 40% at 773K compared to TiO2, which can be due to the presence of dense planar defects. The largest thermoelectric figure of merit Z, 1.6×10-4 K-1 at 773K, was obtained in TiO1.90 hot pressed specimen.

scholarly journals Insights in the Application of Stoichiometric and Non-Stoichiometric Titanium Oxides for the Design of Sensors for the Determination of Gases and VOCs (TiO2−x and TinO2n−1 vs. TiO2)

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6833 ◽  
Author(s):  
Simonas Ramanavicius ◽  
Arunas Ramanavicius
Keyword(s):  
Titanium Oxide ◽  
Synthesis Methods ◽  
Titanium Oxides ◽  
Self Heating ◽  
Nano Structures ◽  
Volatile Organic ◽  
Sensitivity And Selectivity ◽  
Magnéli Phase ◽  
Magneli Phase

In this review article, attention is paid towards the formation of various nanostructured stoichiometric titanium dioxide (TiO2), non-stoichiometric titanium oxide (TiO2−x) and Magnéli phase (TinO2n−1)-based layers, which are suitable for the application in gas and volatile organic compound (VOC) sensors. Some aspects related to variation of sensitivity and selectivity of titanium oxide-based sensors are critically overviewed and discussed. The most promising titanium oxide-based hetero- and nano-structures are outlined. Recent research and many recently available reviews on TiO2-based sensors and some TiO2 synthesis methods are discussed. Some promising directions for the development of TiO2-based sensors, especially those that are capable to operate at relatively low temperatures, are outlined. The applicability of non-stoichiometric titanium oxides in the development of gas and VOC sensors is foreseen and transitions between various titanium oxide states are discussed. The presence of non-stoichiometric titanium oxide and Magnéli phase (TinO2n−1)-based layers in ‘self-heating’ sensors is predicted, and the advantages and limitations of ‘self-heating’ gas and VOC sensors, based on TiO2 and TiO2−x/TiO2 heterostructures, are discussed.

Highly Platinum-Loaded Magnéli Phase Titanium Oxides as a High Voltage Tolerant Electrocatalyst for Polymer Electrolyte Fuel Cells

2015 ◽  
Vol 15 (9) ◽  
pp. 6988-6994
Author(s):  
Didem C. Dogan ◽  
Sun-Mi Hwang ◽  
Eun-Hwa Jang ◽  
Sung-Dae Yim ◽  
Young-Jun Sohn ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
High Voltage ◽  
Polymer Electrolyte Fuel Cells ◽  
Titanium Oxides ◽  
Magnéli Phase ◽  
Magneli Phase

Electrochemical Oxidation of Perfluorooctanesulfonate by Magnéli Phase Ti4O7 Electrode in the Presence of Trichloroethylene

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
Peizeng Yang ◽  
Yaye Wang ◽  
Junhe Lu ◽  
Viktor Tishchenko ◽  
Qingguo Huang ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
First Order ◽  
Degradation Rates ◽  
Oxidation Technology ◽  
Magnéli Phase ◽  
Polyfluoroalkyl Substances ◽  
Titanium Suboxide ◽  
Gas Tight ◽  
Magneli Phase

This study examined the degradation of perfluorooctanesulfonate (PFOS) in electrochemical oxidation (EO) processes in the presence of trichloroethylene (TCE). The EO experiment was performed in a gas-tight reactor using Magnéli phase titanium suboxide (Ti4O7) as the anode. The experimental data demonstrated that 75% of PFOS (2 μM) was degraded at 10 mA/cm2 current density in 30 min without TCE present in the solution, while the presence of 76 μM TCE apparently inhibited the degradation of PFOS, reducing its removal down to 53%. Defluorination ratio suggested that PFOS was significantly mineralized upon EO treatment, and it appeared to be not influenced by the presence of TCE. The respective pseudo-first order rate constants (kobs) of PFOS removal were 0.0471 and 0.0254 min-1 in the absence and presence of TCE. The degradation rates of both PFOS and TCE increased with current density rising from 2.5 to 20 mA/cm2. In the presence of TCE, chloride, chlorate, and perchlorate were formed that accounted for 79.7 %, 5.53%, and 1.51% of the total chlorine at 60 min. This work illustrates the promise of the Magnéli phase Ti4O7 electrode based electrochemical oxidation technology for degrading per- and polyfluoroalkyl substances (PFASs) and co-contaminants in groundwaters.

Thermal Oxidation Behavior of TiAlCrSiN and AlCrTiN Films on HastelloyX

2012 ◽  
Vol 486 ◽  
pp. 400-405 ◽  
Author(s):  
K. Tuchida ◽  
Kessaraporn Wathanyu ◽  
S. Surinphong
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Behavior ◽  
Oxide Scales ◽  
Surface Appearance ◽  
Turbine Engine ◽  
Testing Conditions ◽  
Working Temperature ◽  
Fuel Nozzle ◽  
Higher Temperature ◽  
Scratch Tests

In this paper, the thermal oxidation behavior of TiAlCrSiN and AlCrTiN films coated on hastelloyX substrate, typically used for fuel nozzle in gas turbine engine application, have been studied. The thermal oxidation behavior at 950, 1050 and 1150 °C in controlled atmosphere were investigated. The surface appearance, microstructure, chemical composition and adhesion of films were investigated. The thermal oxidations were observed in all testing conditions showing oxide films at the surface with thicker oxide film at higher temperature. However, spalling of oxide scales was found in both coated and uncoated specimens at 1150°C suggesting the maximum working temperature of < 1150 °C for turbine engine applications. The critical loads corresponding to the full delamination of the thermal oxidation coated specimens were found to be higher than the non-thermal oxidation specimens. The effect of thermal oxidation on damage patterns during scratch tests, i.e. less chipping and cracking for thermal oxidation specimen, were also observed.

Thermal oxidation behavior of hexagonal BC2N

2009 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Qianku Hu ◽  
Qinghua Wu ◽  
Guang Sun ◽  
Xueling Xing ◽  
Julong He ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Behavior

Enhanced thermoelectric properties of the n-type Magnéli phase WO2.90: reduced thermal conductivity through microstructure engineering

2014 ◽  
Vol 2 (33) ◽  
pp. 13492-13497 ◽  
Author(s):  
Gregor Kieslich ◽  
Ulrich Burkhardt ◽  
Christina S. Birkel ◽  
Igor Veremchuk ◽  
Jason E. Douglas ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Magnéli Phase ◽  
Magneli Phase

The thermoelectric properties of the Magnéli phase WO2.90 were investigated, with special attention to how the performance can be altered by changing its microstructure.

Thermal oxidation behavior of ceramic-coated Ni–Cr-base superalloys

2008 ◽  
Vol 202 (22-23) ◽  
pp. 5625-5628 ◽  
Author(s):  
H. Cho ◽  
D.M. Lee ◽  
J.H. Lee ◽  
K.H. Bang ◽  
B.W. Lee
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Behavior
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