Colloidal Processing of SiC with Rare-Earth Ion


Article Preview

The SiC powder of median size 0.8 µm was mixed with polyacrylic acid (PAA, dispersant) in a 0.3 M-R(NO3)3 solution (R=Yb, Y, Gd, Sm, Nd and La) at pH 5 to adsorb uniformly the sintering additive (R3+ ion) on the SiC surface. The addition of PAA to the SiC suspension with R3+ ion increased the amount of R3+ ion fixed to SiC particles. The aqueous 30 vol% SiC suspension with 0.52 mass% PAA and 1.50 mass% R2O3 (as R3+ ion) against the mass of SiC, was consolidated by filtration through a gypsum mold to form green compacts of 50-52 % of theoretical density. The consolidated green compacts were hot–pressed under a pressure of 39 MPa at 1950°C for 2 h in an Ar flow. The green compacts were densified with grain growth to 76 - 99 % relative density. The addition of smaller R3+ ion was effective to enhance the sinterability of SiC and also to achieve smaller grain size of SiC. The sintering mechanisms were discussed based on the analysis of the shrinkage curves of SiC/R2O3 compacts during the hot-pressing.



Edited by:

Hai-Doo Kim, Hua-Tay Lin and Michael J. Hoffmann




S. Tabata et al., "Colloidal Processing of SiC with Rare-Earth Ion", Key Engineering Materials, Vol. 287, pp. 123-128, 2005

Online since:

June 2005




[1] L. M. Wang and W. C. Wei, J. Ceram. Soc. Jpn., 103.

[5] (1995) pp.434-443.

[2] M. A. Mulla and V. D. Krstic, Am. Ceram. Soc. Bull., 70.

[3] (1991) pp.439-443.

[3] Magnani, G. L. Minoccarri and L. Pilotti, Ceram. Inter., 26 (2000) pp.495-500.

[4] J. H. She and K. Ueno, Mater. Res. Bull., 34 [10 - 11] (1999) pp.1629-1636.

[5] Y. Hirata and K. Hidaka, pp.264-272 in Proceedings of International Symposium on Environmental Issues of Ceramics. Edited by H. Yanagida and M. Yoshimura. The Ceramic Society of Japan, Tokyo (1995).

[6] Y. Hirata and W. H. Shih, pp.637-644 in Advances in Science and Technology 14, Proceedings of 9 th Cimtec-World Ceramics Congress, Ceramics : Getting into the 2000's-Part B, Edited by P. Vincenzini, Techna Srl., Faenza (1999).

[7] S. Tabata, S. Sameshima, U. Paik and Y. Hirata, J. Ceram. Proc. Res., 3.

[1] (2002) pp.29-33.

[8] Y. Hirata, S. Tabata and J. Ideue, J. Am. Ceram. Soc., 86.

[1] (2003) pp.5-11.

[9] E. M. Levin, C. R. Robbins and H. F. McMurdie, Fig. 2388 in Phase Diagram for Ceramists, Am. Ceram. Soc., Columbus, Ohio (1969).

[10] J. Marchi, J. C. Bressiani and A. H. A. Bressiani, J. Alloys and Compounds, 344 (2002) pp.170-174.

[11] L. S. Sigl, J. Eur. Ceram. Soc., 23.

[7] (2003) pp.1115-1122.

[12] K. Biswas, G. Rixecker and F. Aldinger, J. Eur. Ceram. Soc., 23.

[7] (2003) pp.1099-1104.

[13] Y. Zhou, K. Hirao, K. Watari, Y. Yamauchi and S. Kanzaki, J. Eur. Ceram. Soc., 24.

[2] (2004) pp.265-270.

[14] W. D. Kingery, J. Appl. Phys., 30 (1959) pp.301-306.

[15] W. D. Kingery and M. Berg, J. Appl. Phys., 26 (1956) pp.1205-1212.