Oxidation Characteristics of Vapor-Plated Tungsten

CORROSION ◽  
1966 ◽  
Vol 22 (10) ◽  
pp. 291-293 ◽  
Author(s):  
VERNON A. NIEBERLEIN
Keyword(s):  
Powder Metallurgy ◽  
Vapor Deposition ◽  
Oxidation Kinetics ◽  
Activation Energies ◽  
Humid Air ◽  
Dry Air ◽  
Oxidation Rates ◽  
Complex Shapes ◽  
Oxidation Characteristics

Abstract Vapor-deposition is being used increasingly for fabricating complex shapes from tungsten. In contrast to conventional tungsten whose oxidation kinetics have been well explored, vapor-deposited material has never been investigated systematically with regard to oxidation. Oxidation rates were run at 600–1000 C (1112–1832 F) in air using a recording balance. Activation energies were calculated and oxidation rates were compared to those of sheet tungsten prepared using powder metallurgy techniques. Humid air and dry air were compared as corroding media.

scholarly journals Tungsten Oxide Based Sensor for Oxygen Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 952 ◽  
Author(s):  
Wangi Sari ◽  
Simon Leigh ◽  
James Covington
Keyword(s):  
Metal Oxide ◽  
Linear Relationship ◽  
Tungsten Oxide ◽  
Spin Coating ◽  
Low Temperatures ◽  
Oxygen Sensor ◽  
High Response ◽  
Humid Air ◽  
Dry Air ◽  
Oxygen Detection

In this paper we report on the development tungsten oxide based chemiresistive sensors for the monitoring of oxygen at low temperatures (T ≤ 400 °C) in dry and humid air. The sensors were deposited onto alumina substrate by a combination of spin coating and a photolithographic process to define the sensing area. Our results show that the sensors comply with a linear relationship over a 0 to 20% concentration range, with a high response towards oxygen. The highest response was observed at 350 °C (ΔR/Ra = 7.8) in humid and in dry air (ΔR/Ra = 18). This result is a significant improvement over our previous experiments and we believe to take the concept of a metal-oxide based oxygen sensor a step closer.

Nasal Mucosal Temperature after Exposure to Cold, Dry Air and Hot, Humid Air

2003 ◽  
Vol 123 (7) ◽  
pp. 851-856 ◽  
Author(s):  
Kristina Liener ◽  
Richard Leiacker ◽  
Jörg Lidemann ◽  
Gerhard Rettinger ◽  
Tilman Keck
Keyword(s):  
Humid Air ◽  
Dry Air ◽  
Exposure To Cold

Oxidation of a Low Carbon, Low Silicon Steel in Air at 600-920°C

2006 ◽  
Vol 522-523 ◽  
pp. 77-86 ◽  
Author(s):  
Rex Y. Chen ◽  
W.Y.Daniel Yuen
Keyword(s):  
Oxidation Kinetics ◽  
Activation Energies ◽  
Silicon Steel ◽  
Oxidation Behaviour ◽  
Low Carbon ◽  
Parabolic Oxidation

The oxidation behaviour of a commercial low carbon, low silicon steel in flowing air at 600-920°C was investigated. Parabolic oxidation kinetics was observed at all temperatures. Three oxidation kinetics zones with different oxidation activation energies were identified. The mechanisms responsible for the different oxidation kinetics are discussed.

scholarly journals The Cyclic Oxidation and Hardness Characteristics of Thermally Exposed Titanium Prepared by Inductive Sintering-Assisted Powder Metallurgy

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 104
Author(s):  
Fahamsyah H. Latief ◽  
El-Sayed M. Sherif ◽  
Agus S. Wismogroho ◽  
Wahyu B. Widayatno ◽  
Hany S. Abdo
Keyword(s):  
Powder Metallurgy ◽  
Single Phase ◽  
Oxide Scales ◽  
Cyclic Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Rates ◽  
Parabolic Law ◽  
Kinetics Of ◽  
Hardness Values

The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-assisted powder metallurgy was evaluated through cyclic tests in air at 700–900 °C for 100 h (5 cycles). In general, the oxidation kinetics of the Ti samples followed the parabolic law and their oxidation rates increased with increasing oxidation temperatures. The rutile form of titanium dioxide (TiO2) was detected by X-ray diffraction in the oxide scales after oxidation at 700 °C and 900 °C. Furthermore, the TiO2 grain size and thickness were significantly influenced by an increase in the oxidation temperature. Lastly, the formation of rutile as a single-phase on the surface of oxidized Ti enhanced the hardness of the oxide scales, whereas the substrate had lower hardness values than the oxide scales due to diffusion of Ti atoms at the surface to form the TiO2 oxide scales.

Effect of cold and warm dry air hyperventilation on canine airway blood flow

1987 ◽  
Vol 62 (2) ◽  
pp. 526-532 ◽  
Author(s):  
E. M. Baile ◽  
R. W. Dahlby ◽  
B. R. Wiggs ◽  
G. H. Parsons ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Left Lung ◽  
Tissue Temperature ◽  
Humid Air ◽  
Dry Air ◽  
Airway Mucosa ◽  
Anesthetized Dogs ◽  
Tracheal Tissue ◽  
Group 2 ◽  
Central Airway

Tracheobronchial blood flow increases with cold air hyperventilation in the dog. The present study was designed to determine whether the cooling or the drying of the airway mucosa was the principal stimulus for this response. Six anesthetized dogs (group 1) were subjected to four periods of eucapnic hyperventilation for 30 min with warm humid air [100% relative humidity (rh)], cold dry air (-12 degrees C, 0% rh), warm humid air, and warm dry air (43 degrees C, 0% rh). Five minutes before the end of each period of hyperventilation, tracheal and central airway blood flow was determined using four differently labeled 15-micron diam radioactive microspheres. We studied another three dogs (group 2) in which 15- and 50-micron microspheres were injected simultaneously to determine whether there were any arteriovenous communications in the bronchovasculature greater than 15 micron diam. After the last measurements had been made, all dogs were killed, and the lungs, including the trachea, were excised and blood flow to the trachea, left lung bronchi, and parenchyma was calculated. Warm dry air hyperventilation produced a consistently greater increase in tracheobronchial blood flow (P less than 0.01) than cold dry air hyperventilation, despite the fact that there was a smaller fall (6 degrees C) in tracheal tissue temperature during warm dry air hyperventilation than during cold dry air hyperventilation (11 degrees C), suggesting that drying may be a more important stimulus than cold for increasing airway blood flow. In group 2, the 15-micron microspheres accurately reflected the distribution of airway blood flow but did not always give reliable measurements of parenchymal blood flow.

Effect of Cold Working and Annealing on Oxidation Rates of Copper in Dry Air at Room Temperature

CORROSION ◽  
1968 ◽  
Vol 24 (12) ◽  
pp. 407-410 ◽  
Author(s):  
P. K. KRISHNAMOORTHY ◽  
S. C SIRCAR
Keyword(s):  
Room Temperature ◽  
Lattice Distortion ◽  
Cold Working ◽  
Oxide Films ◽  
Dry Air ◽  
Oxidation Rates ◽  
Substrate Metal ◽  
Thin Oxide Films ◽  
Thin Oxide ◽  
Kinetics Of

Abstract The effect of plastic deformation and further annealing on the kinetics of growth of thin oxide films on copper at 30 C (86 F) has been investigated. Oxidation rate was found to decrease markedly with increasing deformation. Further annealing showed an increase in the rate, the most pronounced changes occurring during the recrystallization stage. Results are interpreted in the light of Cabrera-Mott theory of growth of very thin oxide films on metals. The change in rate has been related to the concentration of cation vacancies in the Cu2O semi-conductor, which is dependent on the lattice distortion and defect concentration of the substrate metal.

Characterization of Semi-insulating SiC

2006 ◽  
Vol 911 ◽  
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Björn Magnusson ◽  
Erik Janzén
Keyword(s):  
Vapor Deposition ◽  
Thermal Activation ◽  
Deep Level ◽  
Chemical Vapor ◽  
Activation Energies ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

AbstractElectron paramagnetic resonance was used to study defects in high-purity semi-insulating (HPSI) substrates grown by high-temperature chemical vapor deposition and physical vapor transport. Deep level defects associated to different thermal activation energies of the resistivity ranging from ~0.6 eV to ~1.6 eV in HPSI substrates are identified and their roles in carrier compensation processes are discussed. Based on the results obtained in HPSI materials, we discuss the carrier compensation processes in vanadium-doped SI SiC substrates and different activation energies in the material.

Oxidation of PECVD SiC Deposited from Trimethylsilane

1998 ◽  
Vol 555 ◽  
Author(s):  
Peter A. DiFonzo ◽  
Mona Massuda ◽  
James T. Kelliher
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Oxidation Kinetics ◽  
Stoichiometric Composition ◽  
Chemical Vapor ◽  
Oxidation Rates ◽  
Chemical Vapor Deposited ◽  
Kinetics Of ◽  
Sic Films ◽  
Deposition Conditions

AbstractThe stoichiometric composition and oxidation rates ( wet or dry ) of plasma enhanced chemical vapor deposited (PECVD) silicon carbide (SiC) films are effected by the deposition conditions of trimethylsilane (3MS) and carrier gas. We report the oxidation kinetics of SiC thin films deposited in a modified commercial PECVD reactor. A standard horizontal atmospheric furnace in the temperature range of 925–1100°C was used in the oxidation. Oxidized films were measured optically by commercially available interferometer and ellipsometer tools in addition to mechanically using a commercially available profilometer. Activation energies of the parabolic rates were in the range of 20.93 to 335.26 kJ/mol.

Effect of autonomic blockade on tracheobronchial blood flow

1987 ◽  
Vol 62 (2) ◽  
pp. 520-525 ◽  
Author(s):  
E. M. Baile ◽  
S. Osborne ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Blood Gases ◽  
Lung Parenchyma ◽  
Beta Blockade ◽  
Humid Air ◽  
Dry Air ◽  
Arterial Blood ◽  
Autonomic Blockade ◽  
Alpha Blockade ◽  
Group 2

Tracheobronchial blood flow increases two to five times in response to cold and warm dry air hyperventilation in anesthetized tracheostomized dogs. In this series of experiments we have attempted to attenuate this increase by blockade of the autonomic nervous system. Four groups of anesthetized, tracheostomized, open-chest dogs were studied. Group 1 (n = 5) were hyperventilated for 30 min with 1) warm humid [approximately 26 degrees C, 100% relative humidity, (rh)] air followed by bilateral vagotomy, 2) warm humid air, 3) cold (-22 degrees C, 0% rh) dry air, and 4) warm humid air. Groups 2, 3, and 4 (n = 3/group) were hyperventilated for 30 min with 1) warm humid (approximately 41 degrees C, 100% rh) air, 2) warm dry (approximately 41 degrees C) air, 3) warm humid air, and 4) warm dry air. Group 2 were controls. Group 3 were given phentolamine, 0.6 mg/kg intravenously, as an alpha-blockade, and group 4 were given propranolol, 1 mg/kg, as a beta-blockade after warm dry air hyperventilation (period 2). Five minutes before the end of each 30-min period of hyperventilation, measurements of vascular pressures, cardiac output, arterial blood gases, and inspired, body, and tracheal temperatures were measured, and differently labeled radioactive microspheres were injected into the left atrium to make separate measurements of airway blood flow. After the last measurements had been made animals were killed and their lungs were excised. Blood flow to the airways and lung parenchyma was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Oxidation Behaviors of Indefinite Chill Roll and High Speed Steel Materials

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1095
Author(s):  
Liang Hao ◽  
Tuanjie Li ◽  
Zhongliang Xie ◽  
Qingjuan Duan ◽  
Guoyuan Zhang
Keyword(s):  
High Speed ◽  
High Speed Steel ◽  
Isothermal Oxidation ◽  
Humid Air ◽  
Rolling Mills ◽  
Dry Air ◽  
Oxide Phases ◽  
Work Rolls ◽  
Oxidation Behaviors

Indefinite chill (IC) roll and high speed steel (HSS) materials have been widely employed to manufacture work rolls as latter and former stands in hot rolling mills. The oxidation of work rolls is of importance for the surface quality of the rolled workpieces. The isothermal oxidation of the IC and HSS materials was conducted at 650 °C and 700 °C in both dry air and humid air. The isothermal oxidation curves indicate that HSS shows faster kinetics than the IC materials in dry air, whereas the opposite occurred in humid air. The oxide scales of the IC materials after the oxidation in both dry air and humid air are made up of two oxide phases. Two oxide phases were found when the HSS oxidized in the dry air and three oxide phases were found when oxidized in the humid air.

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