Corrosion Behavior and Mechanism of Heat-Resistant Steel T91 in High-Temperature Carbon Dioxide Environment

2019 ◽  
Vol 944 ◽  
pp. 398-403
Author(s):  
Yong Gui ◽  
Zhi Yuan Liang ◽  
Miao Yu ◽  
Qin Xin Zhao

Corrosion behavior of martensitic heat resisting steel T91 in high-temperature carbon dioxide environment at 500-700 °C was investigated. X-ray diffraction, scanning electron microscopy and glow-discharge optical emission spectrometry were employed to characterize the corrosion products. The results showed that the corrosion kinetics of T91 followed a parabolic law with experimental time. The oxide scale thickness of T91 followed an exponential growth law from 500 °C to 700 °C. Internal carburization was detected underneath the corrosion scale. What’s more, the carburization depth was larger than the corrosion scale. The variations of Cr and C elements distribution were discussed.

2020 ◽  
Vol 9 (1) ◽  
pp. 1586-1593
Author(s):  
Tingting Yan ◽  
Shengwen Zhong ◽  
Miaomiao Zhou ◽  
Xiaoming Guo ◽  
Jingwei Hu ◽  
...  

Abstract The extraction of Li from the spent LiFePO4 cathode is enhanced by the selective removal using interactions between HCl and NaClO to dissolve the Li+ ion while Fe and P are retained in the structure. Several parameters, including the effects of dosage and drop acceleration of HCl and NaClO, reaction time, reaction temperature, and solid–liquid ratio on lithium leaching, were tested. The Total yields of lithium can achieve 97% after extraction process that lithium is extracted from the precipitated mother liquor, using an appropriate extraction agent that is a mixture of P507 and TBP and NF. The method also significantly reduced the use of acid and alkali, and the economic benefit of recycling is improved. Changes in composition, morphology, and structure of the material in the dissolution process are characterized by inductively coupled plasma optical emission spectrometry, scanning electron microscope, X-ray diffraction, particle size distribution instrument, and moisture analysis.


Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3267
Author(s):  
Gigliola Lusvardi ◽  
Francesca Sgarbi Stabellini ◽  
Roberta Salvatori

(1) Background: valuation of the bioactivity and cytocompatibility of P2O5-free and CeO2 doped glasses. (2) Methods: all glasses are based on the Kokubo (K) composition and prepared by a melting method. Doped glassed, K1.2, K3.6 and K5.3 contain 1.2, 3.6, and 5.3 mol% of CeO2. Bioactivity and cytotoxicity tests were carried out in simulated body fluid (SBF) solution and murine osteocyte (MLO-Y4) cell lines, respectively. Leaching of ions concentration in SBF was determined by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). The surface of the glasses were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. (3) Results: P2O5-free cerium doped glasses are proactive according to European directives. Cerium increases durability and retards, but does not inhibit, (Ca10(PO4)6(OH)2, HA) formation at higher cerium amounts (K3.6 and K5.3); however, cell proliferation increases with the amount of cerium especially evident for K5.3. (4) Conclusions: These results enforce the use of P2O5-free cerium doped bioactive glasses as a new class of biomaterials.


1989 ◽  
Vol 4 (5) ◽  
pp. 1257-1265 ◽  
Author(s):  
Narottam P. Bansal ◽  
Mark J. Hyatt

Barium aluminosilicate glasses are being investigated as matrix materials in high-temperature ceramic composites for structural applications. Kinetics of crystallization of two refractory glass compositions in the barium aluminosilicate system have been studied by differential thermal analysis (DTA), x-ray diffraction (XRD), and scanning electron microscopy (SEM). From variable heating rate DTA, the crystallization activation energies for glass compositions (wt. %) 10BaO–38Al2O3–51SiO2–1MoO3 (glass A) and 39BaO–25Al2O3–35SiO2–1MoO3 (glass B) were determined to be 553 and 558 kJ/mol, respectively. On thermal treatment, the crystalline phases in glasses A and B were identified as mullite (3Al2O3 · 2SiO2) and hexacelsian (BaO · Al2O3 · 2SiO2), respectively. Hexacelsian is a high-temperature polymorph which is metastable below 1590 °C. It undergoes structural transformation into the orthorhombic form at ∼300 °C accompanied by a large volume change which is undesirable for structural applications. A process needs to be developed where stable monoclinic celsian, rather than hexacelsian, precipitates out as the crystal phase in glass B.


2014 ◽  
Vol 53 (24) ◽  
pp. 12757-12766 ◽  
Author(s):  
Michal Strach ◽  
Renaud C. Belin ◽  
Jean-Christophe Richaud ◽  
Jacques Rogez

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