Effect of the Sintering Additives on the Microstructure and the Properties of Textured Silicon Nitride

Abstract:

Silicon nitride samples without and with 3 wt% of the aligned b-silicon nitride whisker seeds were prepared with 8.2 wt% Er2O3 and 1.9 wt% AlN. After sintering at 2148 K for 4h, the samples exhibited densities higher than 99.5% TD. The microstructures and properties of the samples were compared with those of the samples sintered with 4.8 wt% Y2O3 and 2.2 wt% Al2O3 at 2273 K for 4h. For samples without the whiskers, the sample with 4.8 wt% Y2O3 + 2.2 wt% Al2O3 had coarser microstructures than those with with 8.2 wt% Er2O3 + 1.9 wt% AlN. However, the samples with the whisker seeds, the former sample appeared to have only slightly larger grains than the latter sample in spite of the significant difference in the sintering temperatures. For the samples without the whisker seeds, the room temperature flexural strength was higher for the sample with Er2O3 + AlN. However, for the samples with the aligned whisker seeds, the sample with Y2O3 + Al2O3 exhibited higher room temperature flexural strength than that with Er2O3 + AlN although the average grain width of the former sample was larger than that of the latter sample. In case of the high temperature flexural strength at 1673 K, the flexural strengths of the samples with the whisker seeds were higher than double the strengths of the samples without the whisker seeds. For samples without the whisker seeds, the sample with Er2O3 + AlN exhibited better mechanical properties than that with Y2O3 + Al2O3. However, for the samples with the aligned whisker seeds, the sample with Y2O3 + Al2O3 exhibited better mechanical properties than those with Er2O3 + AlN. The results were explained in terms of the microstructures of the samples.

• Periodical: Key Engineering Materials (Volume 287)
• Pages: 242-246
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.287.242
• Online since: June 2005
• Authors: Dong Soo Park, Y.M. Kim, Byung Dong Hahn, Chan Park
• Keywords: Aluminum Nitride (AlN), Er₂O₃, Flexural Strength, Grain Size, Microstructure, Texture

References

[1] H. Immamura, K. Hirao, M.E. Brito, M. Toriyama and S. Kanzaki, J. Am. Ceram. Soc., 86 (2000) 495.

[2] T. Ohji, K. Hirao, S. Kanzaki, J. Am. Ceram. Soc., 78 (1995) 3125.

[3] D. -S. Park, B. -C. Bae, B. -D. Han, H. -D. Kim, C. Park, Key Eng. Mater., 237 (2003) 175.

[4] D. -S. Park, Y. -M. Kim, C. Park, J. Ceram. Soc. Jpn., in press.

[5] S. Guo, N. Hirosaki, Y. Yamamoto, T. Nishimura and M. Mitomo, Script. Mater., 45 (2001) 86.

[6] J.T. Smith and C.L. Quackenbush, Am. Ceram. Soc. Bull., 59.

[5] (1980) 529.

[7] P. F Becher, S.L. Hwang, H.T. Lin, T.N. Tiegs, pp.87-100 in Tailoring of Mechanical Properties of Si3N4 Ceramics ed. M.J. Hoffmann and G. Petzow, NATO ASI Series E: Applied Sciences Vol. 276 Kluwer Academic Publishers, Dordrecht, The Netherlands, (1994).

DOI: 10.1007/978-94-011-0992-5_6

[8] D. -S. Park, C. -W. Kim, C. Park, Ceram. Eng. Sci. Proc., 19 (1998) 97.

[9] D. -S. Park, B. -C. Bae, B. -D. Hahn, C. Park, J. Am. Ceram. Soc., in review.

[10] D. -S. Park, C. -W. Kim, J. Am. Ceram. Soc., 82 (1999) 780.

[11] D. -S. Park, C-W. Kim, J. Mater. Sci., 34 (1999) 5827.

[12] T. Kawsashima, H. Okamoto, H. Yamamoto, A. Kitamura, J. Ceram. Soc. Jpn., 99 (1991) 320.

[13] C. -W. Li, S. -C. Lui, J. Goldacker, J. Am. Ceram. Soc., 78 (1995) 449.