Effect of Rare-Earth Oxides Additive on Liquid Phase Sintered SiC

Abstract:

The densification of α-SiC occurred by liquid-phase sintering mechanism with AlN-RE₂O₃ (RE=Nd, Gd, Y, Lu) was studied. The total additive content was fixed at 15 wt%. Cold isostatically pressed samples were sintered at 1800-1950 °C under N₂ atmosphere for 1 h. The linear shrinkage and weight loss of the samples were about 17-20% and 2-5%, respectively. The mechanical properties and microstructure of sintered samples were investigated. The experimental results showed that the fracture toughness of samples was 6-8 MPa·m^1/2, the hardness was in the range of 18-21 GPa and the bending strength was in the range of 400-500 MPa. It was found that a decrease in the cationic radius of the rare-earth oxides was accompanied by an increase in hardness and flexural strength of the SiC ceramics, whereas the fracture toughness was improved by incorporating rare-earth oxides of larger cationic radius. The morphology (SEM) of sintered sample showed a fine grained microstructure with equiaxed grains. Fracture mode was intergranular fracture.

• Periodical: Key Engineering Materials (Volumes 602-603)
• Pages: 407-411
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.602-603.407
• Online since: March 2014
• Authors: Yu Hong Chen, Liang Jiang, Li Li Zhang, Zhen Kun Huang, Lan Er Wu
• Keywords: Cationic Radius, Liquid Phase, Mechanical Property, Rare-Earth Oxides, Silicon Carbide (SiC)

References

[1] Rixecker G, Wiedmann I, Rosinus A, et al. J. Eur. Ceram. Soc., 2001, 21: 1013-1019.

[2] Koushik B, Georg R, Fritz A. Ceram. Int., 2005, 31: 703-711.

[3] Kim Y W, Mitomo M, Nishimura T. J. Am. Ceram. Soc., 2001, 84(9): 2060-(2064).

[4] Koushik B, Rixecker G, Aldinger F. Mater. Sci. Eng. A. 2004, 374: 56-63.

[5] Kim Y W, Mitomo M, Nishimura T. J. Am. Ceram. Soc., 2002 85(4): 1007-1009.

[6] 6. Strecker K, Hoffmann M J. J. Eur. Ceram. Soc., 2005, 25: 801-807.

[7] Kay A W, Georg R, Fritz A. J. Eur. Cera. Soc., 2006, 26: 2453-2457.

[8] Zhou Y, Kiyoshi H, Motohiro T, et al. J. Am. Ceram. Soc., 2001, 84 (7): 1642-1644.

[9] Zhou Y, Kiyoshi H, Motohiro T, et al. J. Eur. Ceram. Soc., 2002, 22: 2689-2696.

[10] Rodrguez R F, Oritiz A L, Borrero L O, Guiberteau F. J. Eur. Ceram. Soc., 2010, 30: 119-128.

[11] Rodrguez R F, Oritiz A L, Guiberteau F. J. Eur. Ceram. Soc., 2010, 30: 3209-3217.