Formation mechanisms of interfaces between different TinO2n−1 phases prepared by carbothermal reduction reaction

CrystEngComm ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 524-534 ◽  
Author(s):  
Fang Wang ◽  
Ruyue Shi ◽  
Yimin Lei ◽  
Zhibin Lei ◽  
Ruibin Jiang ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Reduction Reaction ◽  
Thermodynamic Calculations ◽  
Formation Mechanisms ◽  
Tem Analysis ◽  
Xrd And Tem ◽  
Carbothermal Reduction Reaction

The structures of two types of interfaces between different TinO2n−1 phases have been investigated based on comprehensive XRD and TEM analysis. Combined with thermodynamic calculations, the structural evolutions and formation mechanisms of these interfaces are further proposed in detail.

scholarly journals Phase Equilibrium in Carbothermal Reduction Al2O3 → AlN Studied by Thermodynamic Calculations

2017 ◽  
Vol 1 (2) ◽  
pp. 30-37
Author(s):  
Chien Chon Chen ◽  
Chih Yuan Chen ◽  
Hsi Wen Yang ◽  
Yang Kuao Kuo ◽  
Jin Shyong Lin
Keyword(s):  
Carbon Monoxide ◽  
Partial Pressure ◽  
Carbothermal Reduction ◽  
Economic Value ◽  
Reduction Rate ◽  
Aluminum Carbide ◽  
Carbon Activity ◽  
Reduction Reaction ◽  
Thermodynamic Calculations ◽  
Carbothermal Reduction Reaction

As a ceramic with high economic value, aluminum nitride possesses high thermal conductivity, excellent electrical insulation, high mechanical strength and high melting temperature and these all are required in high technologies involving cooling, insulation, thermal expansion and corrosion. This paper deals with thermodynamic parameters which affect the Al2O3→AlN reduction efficiency during a carbothermal reduction. According to the carbothermal reduction reaction γ-Al2O3 + 3C + N2 → AlN + 3CO, if molar mixing ratio of γ-Al2O3:C = 1:3 at 1,601 °C or higher, the γ-Al2O3 can be reduced to AlN. This carbothermal reduction reaction is controlled by main parameters of carbon activity, and partial pressures of nitrogen, carbon monoxide and carbon dioxide. For example, if less carbon is added, a lower carbothermal reduction rate is resulted; however, if extra carbon is added, aluminum carbide (Al4C3) could be produced, or C could remain in AlN. Without N2(g) added in the carbothermal reduction, Al2O3(γ) may react with C to generate Al4C3 at a temperature higher than 2,250 °C. AlN prefers to form with an unity carbon activity, at a lower oxygen partial pressure, a higher carbon monoxide partial pressure, or at a higher temperature. In order to understand the relationship with N2, O2, CO, CO2, C, Al2O3, AlN and Al4C3, the Al-N-C-O system was investigated by thermodynamic calculations.

scholarly journals Mechanism for the formation of SiC by carbothermal reduction reaction using a microwave heating technique

2011 ◽  
Vol 119 (1394) ◽  
pp. 740-744 ◽  
Author(s):  
Shinobu HASHIMOTO ◽  
Syuho OHASHI ◽  
Kiyoshi HIRAO ◽  
You ZHOU ◽  
Hideki HYUGA ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Carbothermal Reduction ◽  
Reduction Reaction ◽  
Carbothermal Reduction Reaction

Tailored MoSi2/SiC composites by mechanical alloying

1993 ◽  
Vol 8 (6) ◽  
pp. 1428-1441 ◽  
Author(s):  
S. Jayashankar ◽  
M.J. Kaufman
Keyword(s):  
Mechanical Alloying ◽  
Carbothermal Reduction ◽  
Reduction Reaction ◽  
Partial Pressures ◽  
Micron Size ◽  
Important Processing ◽  
Sic Composites ◽  
Carbon Additions ◽  
Carbothermal Reduction Reaction

MoSi2-based composites have been synthesized through the mechanical alloying (MA) of elemental molybdenum and silicon powders with and without carbon additions. The interplay between the phase formation sequence in the powders and the microstructural evolution in the consolidated samples is described. It is shown that the glassy SiO2 phase characteristic of conventional powder processed MoSi2 can be effectively eliminated by combining mechanical alloying, carbon additions, and an in situ carbothermal reduction reaction. Using this approach, composites consisting of uniformly distributed micron-size SiC in an MoSi2 matrix can be formed. The effect of important processing variables such as the extent of carbon additions, extraneous iron pickup during MA, partial pressures of oxygen, consolidation temperatures, and consolidation atmospheres is discussed based on the evidence obtained from DTA, TGA, TEM, and XRD.

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