Establishment of Thermally Grown Oxides upon the Early Oxidation Stages of Ni20Cr and Ni30Cr

The performance of Ni-based alloys at high temperature strongly depends on the formation of a protective chromia scale which prevents from fast growth NiO scale. The evolution of the oxide scales will be shown to be strongly dependent on the chromium content especially for the shortest oxidation times. Indeed, transient stages will be reported to condition the subsequent oxidation behavior at longer times until the oxidation rate constant becomes invariant. To this end, a comparative study on the outward and inward diffusion of species upon oxidation at 800°C for short times (0.5 / 1 / 2 / 4 / 8 h) has been evaluated on commercial available Ni20Cr and Ni30Cr alloys through in-situ Raman spectroscopy and supported by post-mortem X-ray diffraction (XRD) as well as scanning electron microscopy coupled to energy dispersive spectrometry (FEG-ESEM / EDS) investigations.

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Investigation of the reaction mechanism of lithium sulfur batteries in different electrolyte systems by in situ Raman spectroscopy and in situ X-ray diffraction

Sustainable Energy & Fuels ◽

10.1039/c6se00104a ◽

2017 ◽

Vol 1 (4) ◽

pp. 737-747 ◽

Cited By ~ 48

Author(s):

W. Zhu ◽

A. Paolella ◽

C.-S. Kim ◽

D. Liu ◽

Z. Feng ◽

...

Keyword(s):

Raman Spectroscopy ◽

Lithium Metal ◽

X Ray Diffraction ◽

In Situ Raman Spectroscopy ◽

X Ray ◽

In Situ Raman ◽

Lithium Sulfur Batteries ◽

Sulfur Battery ◽

Lithium Sulfur

In liithium–sulfur battery the lithium metal surface was analyzed by in situ Raman spectroscopy.

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In Situ Monitoring of Mechanochemical Synthesis of Calcium Urea Phosphate Fertilizer Cocrystal Reveals Water-Based Autocatalysis

10.26434/chemrxiv.9718382 ◽

2019 ◽

Author(s):

Patrick Julien ◽

Luzia S. Germann ◽

Hatem M. Titi ◽

Martin Etter ◽

Robert E. Dinnebier ◽

...

Keyword(s):

Direct Evidence ◽

Phosphate Fertilizer ◽

In Situ Monitoring ◽

Mechanochemical Reaction ◽

X Ray Diffraction ◽

In Situ Raman Spectroscopy ◽

X Ray ◽

In Situ Raman ◽

In Situ Investigation

Using the mechanosynthesis of the calcium phosphate and urea fertilizer cocrystal as a model, we provide the first in situ investigation of autocatalysis in a mechanochemical reaction. The application of in situ Raman spectroscopy and synchrotron X-ray diffraction provided the first direct evidence of a mechanochemical system in which a reaction product (water) mediates the rate of transformation and underpins positive feedback kinetics.

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An Experimental Study of the Formation of Talc through CaMg(CO3)2–SiO2–H2O Interaction at 100–200°C and Vapor-Saturation Pressures

Geofluids ◽

10.1155/2017/3942826 ◽

2017 ◽

Vol 2017 ◽

pp. 1-14 ◽

Cited By ~ 3

Author(s):

Ye Wan ◽

Xiaolin Wang ◽

I-Ming Chou ◽

Wenxuan Hu ◽

Yang Zhang ◽

...

Keyword(s):

Low Temperatures ◽

Fused Silica ◽

X Ray Diffraction ◽

In Situ Raman Spectroscopy ◽

X Ray ◽

In Situ Raman ◽

Geological Processes ◽

Partial Pressures ◽

Increasing Temperature

The metamorphic interaction between carbonate and silica-rich fluid is common in geological environments. The formation of talc from dolomite and silica-rich fluid occurs at low temperatures in the metamorphism of the CaO–MgO–SiO2–CO2–H2O system and plays important roles in the formation of economically viable talc deposits, the modification of dolomite reservoirs, and other geological processes. However, disagreement remains over the conditions of talc formation at low temperatures. In this study, in situ Raman spectroscopy, quenched scanning electron microscopy, micro-X-ray diffraction, and thermodynamic calculations were used to explore the interplay between dolomite and silica-rich fluids at relatively low temperatures in fused silica tubes. Results showed that talc formed at ≤200°C and low CO2partial pressures (PCO2). The reaction rate increased with increasing temperature and decreased with increasingPCO2. The major contributions of this study are as follows:(1)we confirmed the formation mechanism of Mg-carbonate-hosted talc deposits and proved that talc can form at ≤200°C;(2)the presence of talc in carbonate reservoirs can indicate the activity of silica-rich hydrothermal fluids; and (3) the reactivity and solubility of silica require further consideration, when a fused silica tube is used as the reactor in highP–Texperiments.

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