scholarly journals Effect of kerosene combustion atmosphere on the mild steel oxide layer

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Dongbai Xie ◽  
Hao Hong ◽  
Shuwang Duo ◽  
Qiang Li
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
Mild Steel ◽  
Oxide Layer ◽  
Oxidation Products ◽  
Metallic Material ◽  
X Ray ◽  
Combustion Atmosphere ◽  
Fire Scene ◽  
In Fire

AbstractIn arson cases, accelerants were usually used by criminals to achieve the purpose of rapid arson. Therefore, fire investigators aim to determine whether accelerants was used in the fire scene. Metallic material has to react with corrosive gas around it at high temperature and the oxidation products may store the information of reactants. Accelerants present in fire scenes impart some oxidative characteristics on metallic materials. The aim of this work is to figure out the possibility to identify the presence of accelerant in a fire according to the oxidation patterns of metallic material. This paper researched the oxidation behavior of mild steel at high temperature in a simulated flame environment. The surface morphological and cross-sectional microstructural features of the samples were characterized by X-ray diffractions, X-ray photoelectron spectroscopy and scanning electron microscopy with energy-dispersive spectroscopy analysis after oxidation. The carbon in the combustion atmosphere had a carburizing effect on the metal oxide layer. It was mostly C–C, C–O and C=O of organic matter could be used as in fire investigation. Various oxidizing atmosphere composite systems promote the formation of metal oxide layers. And bidirectional oxidation mode in the oxide layer further accelerates the oxidation rate. The (wustite) FeO phase was not found in the oxide layer because of the strong oxidation of the combustion atmosphere. These results offer complementary information in fire characteristics, which combining the characterization of surface scale with traditional chemical analysis of recovering ignitable liquid residues from fire debris are expected to offer crucial information for determining the presence of combustion accelerants at a fire scene.

scholarly journals High-Temperature Oxidation Properties and Microstructural Evolution of Nanostructure Fe-Cr-Al ODS Alloys

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 526
Author(s):  
Zhengyuan Li ◽  
Lijia Chen ◽  
Haoyu Zhang ◽  
Siyu Liu
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Microstructural Evolution ◽  
High Temperature Oxidation ◽  
Oxide Dispersion Strengthened ◽  
Al Alloy ◽  
Temperature Oxidation ◽  
X Ray ◽  
Plasma Sintering ◽  
Ods Alloys

The oxidation behavior and microstructural evolution of the nanostructure of Fe-Cr-Al oxide dispersion strengthened (ODS) alloys prepared by spark plasma sintering were investigated by high-temperature oxidation experiments in air at 1200 °C for 100 h. The formation of Al2O3 scale was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) line scans. The oxidation rate of Fe-Cr-Al ODS alloys is lower than that of conventional Fe-Cr-Al alloys, and the oxide layer formed on the Fe-Cr-Al alloy appeared loose and cracked, whereas the oxide layer formed on the Fe-Cr-Al ODS alloys was adherent and flat. This is due to the high density of dispersed nano-oxides hindering the diffusion of Al element and the formation of vacancies caused by them. In addition, the nano-oxides could also adhere to the oxide layer. Besides, the microstructure of the Fe-Cr-Al ODS alloy had excellent stability during high-temperature oxidation.

High Temperature X-ray Diffraction Study of the Oxidation Products and Kinetics of Uranium–Plutonium Mixed Oxides

2014 ◽  
Vol 53 (24) ◽  
pp. 12757-12766 ◽  
Author(s):  
Michal Strach ◽  
Renaud C. Belin ◽  
Jean-Christophe Richaud ◽  
Jacques Rogez
Keyword(s):  
High Temperature ◽  
Diffraction Study ◽  
Mixed Oxides ◽  
Oxidation Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uranium Plutonium ◽  
Kinetics Of

High Temperature Oxidation Behaviour of Detonation-Gun-Sprayed Cr3C2-NiCr-CeO2 Coatings on Inconel-718 at 900°C

2014 ◽  
Author(s):  
Sekar Saladi ◽  
Jyoti V. Menghani ◽  
Satya Prakash
Keyword(s):  
High Temperature ◽  
Inconel 718 ◽  
High Temperature Oxidation ◽  
Parabolic Rate Constant ◽  
Coated Specimen ◽  
Oxidation Products ◽  
Temperature Oxidation ◽  
X Ray ◽  
Heating And Cooling ◽  
Detonation Gun

The high temperature oxidation behavior of detonation-gun sprayed Cr3C2-NiCr coatings with and without 0.4 wt. % CeO2 additive on Ni-based superalloy inconel-718 is comparatively discussed in the present study. Oxidation studies were carried out at 900°C for 100 cycles in air under cyclic heating and cooling conditions on bare and coated superalloys. The thermo-gravimetric technique was used to establish kinetics of oxidation. X-ray diffraction, SEM/EDAX and X-ray mapping techniques were used to analyze the oxidation products of bare and coated samples. The results indicate that Cr3C2-NiCr-CeO2 coated specimen showed better oxidation resistance. The overall weight gain and parabolic rate constant of Cr3C2-NiCr-CeO2 coated specimen was found to be lowest in the present study signifying that the addition of CeO2 in Cr3C2-NiCr powder has contributed to the development of adherent and dense oxide scale on the coating at elevated temperature.

scholarly journals High Temperature Oxidation Behaviors of CrNx and Cr-Si-N Thin Films at 1000 °C

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 540 ◽  
Author(s):  
Bih-Show Lou ◽  
Yue-Chyuan Chang ◽  
Jyh-Wei Lee
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Oxide Layer ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Oxidation Test ◽  
Parabolic Rate ◽  
Oxidation Behaviors

The high temperature oxidation performance of nitride thin films has become an important issue when they are used as protective coatings on dry cutting tools or on die casting molds. In this study, the high temperature oxidation behaviors of CrNx and Cr-Si-N thin films were investigated at 1000 °C for 6 h in ambient air. The CrNx and Cr-Si-N thin films were prepared by a bipolar asymmetric pulsed direct-current (DC) magnetron sputtering system. Cr-Si-N films with silicon content ranging from 3.9 to 12.2 at.% were deposited by adjusting the Si target power. A thermogravimeter was adopted to study the oxidation kinetics of thin films. The weight gains were measured to calculate the parabolic rate constants of thin films. X-ray diffraction, X-ray mapping, and Auger electron spectroscopy were employed to study the microstructure and elemental redistributions of oxidized thin films. The as-deposited CrNx and Cr-Si-N thin films consisted of CrN and Cr2N mixed phases. The faceted Cr2O3 surface oxides, porous inner oxide layer, and oxygen-containing CrSi2 phases were found for the CrN film after oxidation test. On the other hand, the Cr-Si-N film containing 12.2 at.% Si showed a dense surface oxide layer and a thick and compact nitride layer, which indicates its best oxidation resistance. The high temperature oxidation resistance of Cr-Si-N thin films was improved by increasing Si content, due to the amorphous matrix contained nanocomposite microstructure and the formation of amorphous silicon oxide to retard the diffusion paths of oxygen, chromium, silicon, and nitrogen. The lowest parabolic rate constant of 1.48 × 10–2 mg2/cm4/h was obtained for the 12.2 at.% Si contained Cr-Si-N thin films, which provided the best oxidation resistance at 1000 °C for 6 h in this work. It should be noted that the residual tensile stress of thin film had a detrimental effect on the adhesion property during the oxidation test.

Kinetics of the oxidation of Ba2 YCu3Ox ceramics

1988 ◽  
Vol 3 (4) ◽  
pp. 619-625 ◽  
Author(s):  
H. M. O'Bryan ◽  
P. K. Gallagher
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Large Volume ◽  
Linear Relation ◽  
Oxygen Stoichiometry ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Kinetics Of ◽  
Volume Decrease

The kinetics of the oxidation of dense and porous samples of Ba2 YCu3Ox ceramic have been determined by gravimetric analysis at 400–700 °C. At 600 °C and above, the rate decreases as the thickness of the oxidized layer increases. At 500 °C and below, the kinetics show a linear relation that indicates that the oxidized layer does not protect the ceramic. Dilatometric, microscopic, and high-temperature x-ray data suggest that fractures in the oxide layer at the lower temperatures are caused by the large volume decrease that accompanies the change in oxygen stoichiometry.

Interface chemistry and electrical characteristics of 4H-SiC/SiO2 after nitridation in varying atmospheres

2018 ◽  
Vol 6 (44) ◽  
pp. 12079-12085 ◽  
Author(s):  
Anna Regoutz ◽  
Gregor Pobegen ◽  
Thomas Aichinger
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
High Power ◽  
Photoelectron Spectroscopy ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Interface Chemistry ◽  
X Ray ◽  
Immense Potential

SiC has immense potential as the semiconductor for future high power metal–oxide–semiconductor devices. X-ray photoelectron spectroscopy (XPS) to systematically study the 4H-SiC/SiO2 interface after high temperature nitridation treatments in a variety of atmospheres.

The Study on High-Temperature Oxidation Law of 20CrMo Steel in the Regenerative Heating Furnace

2011 ◽  
Vol 291-294 ◽  
pp. 778-781
Author(s):  
Tao Wang ◽  
Yan Hong Leng ◽  
Lian Sheng Chen
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Heating Furnace ◽  
Temperature Oxidation ◽  
Thermodynamics And Kinetics ◽  
Working Principle ◽  
Combustion Atmosphere ◽  
Special Atmosphere

The special atmosphere of oxidation and reduction combustion in regenerative heating furnace is confirmed by anglicizing working principle of the furnace, and the growth and nature of steel’s oxide layer is influenced by the special combustion atmosphere. From the respects of thermodynamics and kinetics, the high-temperature oxidation regular of 20CrMo steel is studied. The oxidative production include steady oxide of Fe2O3、Fe3O4、FeO.The oxide layer grow slowly when temperature below 1100°C, but speedily when it is over1100°C. With the commutation of valve, the combustion atmosphere of regenerative heating furnace alternates between oxidation and reduction. Following the "intermittent" growth law, 20CrMo steel is in the process of “growth - decomposition –growth”.

scholarly journals Experimental Study on the Oxidation and Diffusion Behavior of Inconel 625 and Tool Materials

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 471
Author(s):  
Erliang Liu ◽  
Ning Wang ◽  
Jin Qi ◽  
Zhichao Xu ◽  
Xia Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Products ◽  
Inconel 625 ◽  
Ceramic Tool ◽  
Temperature Oxidation ◽  
X Ray ◽  
Suitable Material ◽  
Tool Materials ◽  
Coated Carbide ◽  
And Diffusion

Oxidation and diffusion simulation experiments were conducted to choose the most suitable material for cutting the Inconel 625 superalloy. Three tool materials, WC/Co, coated carbide, and ceramic were used as tool materials in the oxidation simulation experiment. The three tool materials were heated for 30 min in a high-temperature furnace, and the high-temperature oxidation products were examined with scanning electron microscopy and X-ray diffraction (XRD). Tools were heated for 90 min in a vacuum tube furnace. The element diffusion behaviors of Inconel 625 and the tool materials were analysed with energy-dispersive X-ray spectroscopy and XRD. Some of the WC and Co in the WC/Co and coated carbide tool materials was oxidized to WO3, Co3O4, and CoWO4, and the oxidation reaction became more intense as the temperature increased. For the ceramic tool, only TiC was oxidized to TiO2, which indicates good oxidation resistance. In the diffusion couple experiments, the diffusion levels of the three tool materials increased with temperature, but the degree of influence differed. Diffusion of elements was hindered by the (Al, Ti) N coating of the coated carbide and effectively inhibited by the Al2O3 in the ceramic tool. In terms of oxidation and diffusion, the most suitable tool material for cutting Inconel 625 was the ceramic, followed by the coated carbide and then WC/Co.

Influence of the Si-Content on the High Temperature Oxidation Behaviour of NiCrBSi-Coatings

2014 ◽  
Vol 216 ◽  
pp. 79-84
Author(s):  
Carsten Strübbe ◽  
Gabriela Marginean ◽  
Viorel Aurel Serban
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Elevated Temperatures ◽  
Sample Surface ◽  
Oxidation Behaviour ◽  
Metal Dusting ◽  
Temperature Oxidation ◽  
X Ray ◽  
Si Content

The high temperature oxidation behaviour of Ni-Cr-B-Si coatings with a higher Si-content was investigated in order to evaluate the suitability of such materials especially for novel applications concerning highly aggressive environments like metal dusting. Metal dusting is a corrosion phenomenon that occurs in reducing-, carbon-supersaturated (ac>1) gaseous atmosphere, containing CO, H2, CO2 and H2O, at elevated temperatures between 400 and 800°C. Metal dusting reactions can be classified into two types. The first one concerns Fe-alloys, where Fe3C is growing on the surface. The second one is related to the reaction of Ni, Co and their alloys, where the destruction takes place through inward growth or direct ingrowth of graphite, without forming the metastable Fe3C. Regarding to the literature, metal dusting is typically encountered in industrial furnaces, but mainly in the chemical or petrochemical industry. The way to suppress metal dusting is to stop the dissociation of the carbon source or to stop the carbon ingress in the material. One possibility in order to avoid the carburization of Fe, Ni, Co and their alloys is to preoxidize the samples. Based on the reducing atmosphere, where metal dusting occurs, the isothermal outsourcing for the formation of a protective Al-, Cr- or Si-oxide layer on the samples in air is mostly necessary. The role of a stable Al2O3 and Cr2O3-layer on the sample as a diffusion barrier against the carbon ingress, based on their low solubility for carbon, has already been investigated and proved by many scientists. The formation of a protective and thermodynamically very stable SiO2 scale was also investigated. Within the scope of this work, the influence of a higher Si-content (4,5 wt%) in NiCrBSi-alloys, depending on the temperature, was analyzed. For this purpose the samples were oxidized in air at 600, 700 and 800°C respectively. The surface morphology and the phase composition of the grown oxide scales were characterized by means of scanning electron microscopy combined with energy dispersive X-ray (SEM/EDX) and by X-ray diffraction (XRD) technique. The experimental results demonstrate the importance of silicon content on the coatings properties, respectively on the stability of the formed oxide scale (free of micro cracks, no spallation). This element is able to form beside chromium, a dense oxide layer on the sample surface, protecting it against further degradation induced by the atmosphere in different high temperature applications. Moreover, the increased chromium content of the feedstock powder (from 10 wt% in previous work to 12,5 wt%) demonstrated that the Ni-Cr-B-Si coatings exposed at 600°C, 700°C as well as at 800°C were not susceptible to internal oxidation.

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