Air and Wet Air Oxidation of 9Cr-3Co-3W Creep Resistant Ferritic Steel at 650 °C

2013 ◽  
Vol 634-638 ◽  
pp. 1685-1689
Author(s):  
Shan Tang ◽  
Xi Tang ◽  
Z.D. Xiang
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Ferritic Steel ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Rate Law ◽  
Cr2o3 Scale ◽  
Weight Measurement ◽  
Experimental Creep ◽  
Power Rate

The new experimental creep resistant ferritic steel of the 9Cr-3Co-3W type was oxidised at 650 °C in air and wet air. The oxidation kinetics was measured by intermittent weight measurement. The scales formed were analysed using techniques of XRD, SEM and EDS. The results showed that the oxidation rate was more than a magnitude faster in wet air than in air. The oxidation kinetics in air obeyed the parabolic rate law of oxidation only in a limited oxidation period of up to 1726 h whereas it did not follow any power rate law of oxidation in wet air. The steel cannot form a protective Cr2O3 scale either in air or in wet air at 650 °C. Instead, the scale formed in air consisted of an outer (Fe0.6Cr0.4)2O3 layer and an inner Cr-rich (Fe,Cr)2O3 layer containing Cr2O3 particles, but in wet air it consisted of an outer Fe3O4 layer and an inner (Fe,Cr)3O4 layer.

Air Oxidation of Porous Cu-35wt.%Ni-(5,10,15) wt%Cr Alloys at 650°C

2013 ◽  
Vol 365-366 ◽  
pp. 987-990
Author(s):  
Jian Chen ◽  
Zi Han Huang ◽  
Yan Jie Ren ◽  
Wen Wen ◽  
Xiang Wu Xiao ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Air Oxidation ◽  
Internal Oxide ◽  
Rate Law ◽  
Cr Content ◽  
Ni Content ◽  
Initial Stage ◽  
Parabolic Rate

The oxidation behavior of porous Cu-Ni-Cr alloys containing approximately 5,10 and 15 wt.%Cr, but with a similar Ni content of 35 wt.%, was studied at 650°C in air. The results showed that the oxidation of alloys follows linear law at initial stage and then the parabolic rate law. Continuous external scales of CuO and Cu2O formed on the alloys. Some internal oxide of were observed. In addition, with increase of Cr content, the oxidation rate decreased slightly.

Effects of Yttrium on Cyclic Oxidation Resistance of Co-10Cr-5Al Alloy

2013 ◽  
Vol 785-786 ◽  
pp. 844-847
Author(s):  
Jun Huai Xiang ◽  
Xian Chao Xu ◽  
Ling Yun Bai ◽  
Yun Xiang Zheng ◽  
Huai Shu Zhang
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Local Zone ◽  
Rate Law ◽  
Parabolic Rate

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without Y in atmosphere at 800 °C was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the behavior from irregular oxidation kinetics to approximate parabolic rate law. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of Y impaired the adhesion of the scale. Over-doped Y agglomerated in local zone plays an adverse role in the oxidation process by accelerating the oxidation rate.

scholarly journals High-Temperature Oxidation Kinetics of Additively Manufactured NiTiHf

2020 ◽  
Author(s):  
Hediyeh Dabbaghi ◽  
Mohammadreza Nematollahi ◽  
Keyvan Safaei Baghbaderani ◽  
Parisa Bayatimalayeri ◽  
Mohammad Elahinia
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Transformation Temperatures ◽  
X Ray ◽  
Rate Law ◽  
Kinetics Of

Abstract NiTi-based high-temperature shape memory alloys (HTSMAs) such as NiTiHf have been utilized in a broad range of applications due to their high strength and work output, as well as, their ability to increase the transformation temperatures (TTs). Recently, additive manufacturing techniques (AM) have been widely used to fabricate complex shape memory alloy components without any major modifications or tooling and has paved the way to tailor the manufacturing and fabrications of microstructure and critical properties of their final parts. NiTi alloys properties such as transformation temperatures can be significantly altered due to oxidation, which can occur during the manufacturing process or post-processing. In this work, the oxidation behavior of Ni-rich NiTi20Hf shape memory alloys, which was fabricated by the selective laser melting (SLM) method, is evaluated. Thermogravimetric analysis (TGA) is used to assess the kinetic behavior of the oxidation at different temperature ranges of 500, 700, and 900 °C for 20 hours in the air. After oxidation, to evaluate the microstructure and chemical composition X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) was conducted. The isothermal oxidation kinetics of conventional NiTi20Hf alloys were studied, and the results were compared to AM samples. Results show a two-stage oxidation rate at which oxidation increased with the high rate at the initial stage. As the oxidation time increased, the oxidation rate gradually decreased. The oxidation behavior of NiTiHf alloys initially obeyed logarithmic rate law and then followed by parabolic rate law. SEM results showed the formation of a multi-layered oxide scale, including TiO2, NiTiO3, and Hf oxide.

Catalytic wet air oxidation of dyeing and printing wastewater

1997 ◽  
Vol 35 (4) ◽  
pp. 311-319 ◽  
Author(s):  
L. Lei ◽  
X. Hu ◽  
H. P. Chu ◽  
G. Chen ◽  
P. L. Yue
Keyword(s):  
High Pressure ◽  
Reaction Time ◽  
Textile Industry ◽  
Porous Alumina ◽  
Supported Catalyst ◽  
Metal Salts ◽  
Treated Wastewater ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation

The treatment of dyeing and printing wastewater from the textile industry by oxidation was studied. The reaction was carried out in a two-litre high pressure reactor. In order to promote the oxidation of organic pollutants present in the wastewater, experiments were conducted using various catalysts including metal salts, metal oxides, and porous alumina supported metals. All catalysts tested were able to enhance the conversion of organic compounds in wastewater, shorten the reaction time, and lower the reaction temperature. The alumina supported catalyst has an advantage over other catalysts in that it can be easily separated from the treated wastewater by filtration and recycled. The conditions in preparing the catalyst supported by porous alumina were experimentally optimised.

Synthesis, characterization and activity of W–La/CexZr1−xO2 catalysts in the catalytic wet air oxidation of phenol

2021 ◽  
Author(s):  
Mohamed Achraf Bouabdellah ◽  
Itidel Belkadhi ◽  
Lassaad Ben Hammouda ◽  
Gwendoline Lafaye ◽  
Francisco Medina Cabello ◽  
...  
Keyword(s):  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Oxidation Of Phenol

scholarly journals Life cycle thinking case study for catalytic wet air oxidation of lignin in bamboo biomass for vanillin production

2021 ◽  
Vol 23 (4) ◽  
pp. 1847-1860
Author(s):  
Christopher S. McCallum ◽  
Wanling Wang ◽  
W. John Doran ◽  
W. Graham Forsythe ◽  
Mark D. Garrett ◽  
...  
Keyword(s):  
Life Cycle ◽  
Crude Oil ◽  
Kraft Lignin ◽  
Life Cycle Thinking ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation

A life cycle thinking analysis (LCT) conducted on the production of vanillin via bamboo wet air oxidation compared to vanillin production from crude oil or kraft lignin.

Comprehensive Evaluation of Non-Catalytic Wet Air Oxidation as a Pretreatment to Remove Pharmaceuticals from Hospital Effluents

2021 ◽  
Author(s):  
Valérie Boucher ◽  
Margot Beaudon ◽  
Pedro Ramirez ◽  
Pascal Lemoine ◽  
Kalyssa Volk ◽  
...  
Keyword(s):  
Surface Waters ◽  
Comprehensive Evaluation ◽  
Chemical Processes ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Highly Efficient ◽  
Hospital Effluents ◽  
Promising Solution

Removal of pharmaceuticals from wastewater using chemical processes is a promising solution to mitigate pollution in drinking and surface waters. Non-catalytic wet air oxidation (WAO) is a highly efficient advanced...

Wet air oxidation with tubular ceramic membranes modified with polyelectrolyte/Pt nanoparticle films

2009 ◽  
Vol 91 (1-2) ◽  
pp. 180-188 ◽  
Author(s):  
David M. Dotzauer ◽  
Ali Abusaloua ◽  
Sylvain Miachon ◽  
Jean-Alain Dalmon ◽  
Merlin L. Bruening
Keyword(s):  
Ceramic Membranes ◽  
Pt Nanoparticle ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Nanoparticle Films

Formation of synthetic analogues of double metal-hydroxy carbonate minerals under controlled pH conditions: I. The synthesis of pyroaurite and reevesite

Clay Minerals ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 161-179 ◽  
Author(s):  
H. C. B. Hansen ◽  
R. M. Taylor
Keyword(s):  
Oxidation Rate ◽  
Reasonable Agreement ◽  
Single Phase ◽  
Morphological Features ◽  
Air Oxidation ◽  
Synthetic Analogues ◽  
Synthesis Technique ◽  
Homogeneous Product ◽  
Ph Conditions ◽  
Hydroxy Carbonate

AbstractTwo-layered Fe(III)-M(II) hydroxy carbonates (M(II) = Ni or Mg) have been synthesized by induced hydrolysis using controlled air oxidation of an aqueous Fe(II)-M(II) mixture (M(II)/Fe(II) ratio >3) at a pH below which the hydroxide of the M(II) cation precipitates. The crystalline, homogeneous product can be a single phase consisting of very thin circular to hexagonal plates (0·2–0·8 µm diam.). For synthetic reevesite (Ni(II)-Fe(III) hydroxy carbonate), stable spherular aggregates are formed. The well crystallized products have an M(II)/Fe(III) ratio of about two. However, by varying the pH, the initial M(II)-Fe(III) ratio and the oxidation rate, the M(II)/Fe(III) ratio in the product and its crystallinity can be varied. The derived formulae are in reasonable agreement with the known composition of pyroaurite-type compounds. Possible synthesis pathways are discussed. The ability to control some physical and morphological features of the products indicates that the synthesis technique could prove advantageous in the preparation of certain catalyst precursors.

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