Study of High-Temperature Oxidation Behavior of Antimony and Bismuth Tellurides by Thermopiezic Analysis and Powder X-Ray Diffraction: A Case Study of Thermochemistry

2019 ◽  
pp. 157-204
Author(s):  
Makio Kurisu
Author(s):  
Xin Zhang ◽  
Zehua Wang ◽  
Jinran Lin

AbstractFeCrBAlMo coating was deposited on an AISI 20 steel substrate by high velocity arc spraying (HVAS). Compared with FeCrBSiMo coating and pristine AISI 20 steel, the microstructure and high temperature oxidation behavior of FeCrBAlMo coating were investigated by optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Meanwhile, the bonding strength of the coatings was also measured. The results indicated that both coatings were composed of α(Fe,Cr) and Fe


2010 ◽  
Vol 105-106 ◽  
pp. 162-164
Author(s):  
Hong Bo Chen ◽  
Song He Meng

High temperature oxidation testing was carried out on hot-pressed ZrB2-SiC-graphite composite by using high electric current heating. The composites oxidation behavior was investigated, the temperature of oxidized specimens was above 2000°C. The results found that the UHTC composite was ruptured at oxidized temperature 2055°C. The microstructure of surface and cross-section of posttest samples were investigated by scanning electron microscopy along with energy and X-ray diffraction. The failure mechanism of rupture was also discussed.


2018 ◽  
Vol 921 ◽  
pp. 168-176
Author(s):  
Chang Hai Zhou ◽  
Rui Yun Pan ◽  
Hai Tao Ma

The oxidation behavior of Fe-20Ni alloy under compressive stress in air was studied at 800, 900 °C. The results examined by using scanning electron microscope (SEM) and X-ray diffraction (XRD) indicates that the oxide scales were consisted of an external scale and a subscale which has an intragranular scale (above 5 h at 800 °C and 900 °C) and an intergranular scale. Compared with the unstressed specimen, the growth kinetics of external scale was accelerated by an applied compressive stress. Besides, the compressive stress induced an increase in the growths of intragranular scale and intergranular scale formed on the specimens oxidized at 900 °C. However, the effect of compressive stress on the growth of intergranular scale and intragranular scale was not obvious in the case of 800°C. In addition, cracks developed in the subscale for the specimens oxidized under 2.5 MPa compressive stress when the oxidation time exceeded 20 h.


2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Grzegorz Moskal ◽  
Damian Migas ◽  
Dawid Niemiec ◽  
Agnieszka Tomaszewska

Cobalt-based γ–γ′ superalloys are novel heat-resistant materials suitable for high-temperature applications, such as components of the turbine engine. These alloys exhibit favorable strength and corrosion resistance at high temperatures owing to the γ–γ′ microstructure, analogous to that of Ni-based superalloys. The aim of this paper is to evaluate the oxidation behavior of basic Co-9Al-9W (at%) and new tungsten-free Co-10Al-5Mo-2Nb (at%) alloys at elevated temperatures. The investigation is concerned with thermogravimetric studies in the temperature range of 40–1200 °C. The oxidized surfaces after high temperature oxidation have been characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis (XRD).


2018 ◽  
Vol 274 ◽  
pp. 9-19
Author(s):  
Guo Tao Zhang ◽  
Yong Zheng ◽  
Yi Jie Zhao ◽  
Wei Zhou ◽  
Jia Jie Zhang ◽  
...  

Ti (C,N)-based cermets with varying WC additions (Ti (C0.6N0.4)-36Ni-12Mo-1C-xWC, x = 0, 3, 6 and 9 wt%) were prepared by conventional powder metallurgy techniques. The microstructure and mechanical properties of all four Ti (C,N)-based cermets were investigated. Isothermal oxidation of all four cermets were also investigated in air at 800°C up to 100 h using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). The grains of Ti (C,N)-based cermets became more homogeneous with the increase of WC content. The TRS and fracture toughness increased with the increase of WC content and then decreased when WC content exceeded 6wt%, but hardness decreased continuously with the increase of WC content. The oxide scales formed on the surface of all four samples during the oxidation process were porous and multi-layered, consisting of NiO outerlayer and TiO2 based innerlayer, respectively. The thickness of the oxide scales and oxidation rates increased with the increase of WC content, especially when the content of WC addition reached 9wt%. The cermet with 6wt% WC addition showed excellent mechanical properties and acceptable high temperature oxidation resistance.


2017 ◽  
Vol 62 (2) ◽  
pp. 1099-1104
Author(s):  
Yong Hwan Kim ◽  
Jeong-Jung Oak ◽  
Ki-Chang Bae ◽  
Wook Jin Lee ◽  
Yong Ho Park

AbstractThe oxidation kinetics of forged 12Cr-MoVW steel was investigated in an air (N2+O2) atmosphere at 873-1073 K (Δ50 K) using thermogravimetric analysis. The oxidized samples were characterized using X-ray diffraction, and the surface and cross-sectional morphologies were examined using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The forged 12Cr-MoVW steel samples exhibited parabolic behavior and a low oxidation rate compared with their as-cast counterparts. A protective oxide layer was uniformly formed at relatively low temperature (≤973 K) for the forged samples, which thus exhibited better oxidation resistance than the as-cast ones. These oxides are considered solid-solution compounds such as (Fe, Cr)2O3.


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