Environment-Friendly Preparation of Reaction-Bonded Silicon Carbide by Addition of Boron in the Silicon Melt

Reaction-bonded silicon carbide ceramics were sintered by infiltration of Si and B–Si alloy under an argon atmosphere at different temperatures. The element boron was added to the silicon melt to form a B–Si alloy first. The mechanical properties of samples were improved by infiltration of the B–Si melt. The samples infiltrated with the Si-only melt were found to be very sensitive to experimental temperature. The bending strengths of 58.6 and 317.0 MPa were achieved at 1530 and 1570 °C, respectively. The sample made by infiltration of B–Si alloy was successfully sintered at 1530 °C. The relative density of the sample was more than 90%. The infiltration of B–Si alloy reduced the sintering temperature and the bending strength reached 326.9 MPa. The infiltration mechanism of B–Si alloy is discussed herein.

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Effect of Sintering Temperature on Density and Mechanical Properties of Solid-State Sintered Silicon Carbide Ceramics and Evaluation of Failure Origin

Journal of Materials Engineering and Performance ◽

10.1007/s11665-018-3397-4 ◽

2018 ◽

Vol 27 (6) ◽

pp. 2960-2966 ◽

Cited By ~ 3

Author(s):

Dulal Chandra Jana ◽

Prasenjit Barick ◽

Bhaskar Prasad Saha

Keyword(s):

Mechanical Properties ◽

Silicon Carbide ◽

Solid State ◽

Sintering Temperature ◽

Carbide Ceramics ◽

Silicon Carbide Ceramics ◽

Sintered Silicon

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Sintering of Silicon Carbide Ceramics with Co-Addition of Gadrinium Oxide and Silica and their Mechanical Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.484.117 ◽

2011 ◽

Vol 484 ◽

pp. 117-123

Author(s):

Toyohiko Yano ◽

Yasutaka Horie ◽

Masamitsu Imai ◽

Katsumi Yoshida

Keyword(s):

Mechanical Properties ◽

Grain Boundary ◽

Bending Strength ◽

Sintering Temperature ◽

Applied Pressure ◽

Boundary Phase ◽

Homogeneous Distribution ◽

Carbide Ceramics ◽

Co Addition ◽

Silicon Carbide Ceramics

Effects of simultaneous addition of SiO2 and gadrinium oxide on densification of SiC ceramics were examined, and relation between microstructure and their mechanical properties were discussed. Total 11wt% of Gd2O3 and SiO2 were mixed with fine -SiC powder. The weight of Gd2O3 in (Gd2O3 + SiO2) were set as 0, 20, 40, 60, 80 and 100%. The mixture was hot-pressed at 1950oC under 40 MPa applied pressure for 1 h. In the case of 40Gd2O3 and 80Gd2O3 compositions, the effect of sintering temperature from 1900 to 2000oC was also examined. The bulk density increased with increasing Gd2O3 content at the sintering temperature of 1950oC. Bending strength of the sintered bodies also improved with increasing Gd2O3 content generally, but at 40Gd2O3 composition, the maximum over ~800 MPa was observed. Young’s modulous, Vickers hardness and fracture toughness also increased with increasing Gd2O3 content. The distribution of grain boundary phase was not homogeneous. Evaporation of additives, mainly SiO2, caused non-homogeneous distribution of grain boundary phase between outside and inside of sintered bodies. High temperature bending strength of 80Gd2O3 specimen was superior than that of 40Gd2O3 specimen.

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