Sains Malaysiana 41(8)(2012): 1005–1009

Densification and Mechanical Properties of Electroconductive Si3N4 -Based

Composites Prepared by Spark Plasma Sintering

(Penumpatan dan Sifat-Sifat Mekanik Komposit Berasaskan Si3N4 disediakan

Melalui Pensinteran Percikan Plasma)

Norhayati Ahmad*

Department of Materials Engineering, Faculty of Mechanical Engineering

Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

Hidekazu Sueyoshi

Department of Nano-structure and Advanced Materials, Graduate School of Science and Engineering

Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065 Japan

Received: 25 January 2010 / Accepted: 25 March 2011

ABSTRACT

Si3N4-TiN composites were prepared by conventional powder processing (SPS1) and in-situ reaction sintering (SPS2). Rapid densification of SPS was achieved for sample SPS1 and SPS2 within a few minutes at low temperature. Sample SPS1 sintered at 1550ºC showed rapid transformation of α to β Si3N4 while for sample SPS2 sintered at 1350ºC, a significant degree of α to β Si3N4 transformation was achieved. Homogeneous distribution of equiaxed TiN grains in matrix Si3N4 resulting in high hardness (21.7 GPa) and bending strength (621 MPa) for sample SPS1 sintered at 1550ºC. Elongated TiN grains as the reinforcement of Si3N4 matrix composites was found to increase the toughness (8.39 MPa m1/2) of sample SPS2 sintered at 1350ºC. The composites prepared by SPS2 sintered at 1250-1350ºC had low electrical resistivity and could be machined by electrical discharge machining (EDM).

Keywords: Densification; mechanical properties; silicon nitride-titanium nitride composites; spark plasma sintering

ABSTRAK

Komposit Si3N4-TiN dihasilkan dengan kaedah pemprosesan serbuk yang lazim (SPS1) dan pensinteran tindak balas in-situ (SPS2). Pemandatan yang tinggi diperoleh daripada sampel SPS1 dan SPS2 selama beberapa minit pada suhu yang rendah. Sampel SPS1 yang disinter pada suhu 1550ºC menunjukkan transformasi daripada α ke β Si3N4 yang pantas, manakala sampel SPS2 yang disinter pada suhu 1350ºC menunjukkan transformasi α ke β Si3N4 ke tahap yang signifikan. Taburan butiran TiN yang berbentuk sepaksi secara seragam dalam matrik Si3N4 memberikan kekerasan (21.7 GPa) dan kekuatan lenturan (621 MPa) yang tinggi bagi sampel SPS1 yang disinter pada suhu 1550ºC. Butiran TiN yang berbentuk panjang sebagai penguat dalam matrik komposit Si3N4 boleh meningkatkan keliatan (8.39 MPa m1/2) bagi sampel SPS2 yang disinter pada suhu 1350ºC. Sampel SPS2 yang disinter pada suhu 1250-1350ºC mempunyai rintangan elektrik yang rendah dan boleh dimesin dengan pemesinan nyahcas elektrik (EDM).

Kata kunci: Komposit silikon nitrat-titanium nitrat; pensinteran percikan plasma (SPS); penumpatan; sifat mekanikal

REFERENCES

Bellosi, A., Guicciardi, S. & Tampieri, A. 1992. Development and characterization of electroconductive Si3N4-TiN composites J. Eur. Ceram. Soc. 9: 83-93.

Bowen, L.J., Carruthers, T.G. & Brook, R.J. 1978. Hot-pressing of silicon nitride with yttrium oxide and lithium oxide as additives: J. of the Am. Cer. Soc. 61: 335-339.

Bowen, L.J., Weston, R.J., Carruthers, T.G. & Brook, R.J. 1978. Hot-pressing and the α-β phase transformation in silicon nitride. J. of Mat. Sc. 13: 341-350.

Gao, L., Hong, J.S., Miyamoto, H. & Torre, S.D.D.L. 1998. Superfast densification of oxide ceramics by spark plasma sintering. J. Inorg. Mater. 13: 18-22.

Gao, L. & Miyamoto, H. 1997. Spark Plasma Sintering Technology. J. Inorg. Mater. 12: 129-133.

Kall, P.O. 1988. Quantitative phase analysis of Si3N4-based Materials Chem. Scr. 28: 439-4368.

Lewis, M.H., Bhatti, A.R., Lumby, R.J. & North, B. 1980. The microstructure of sintered Si-Al-O-N ceramics, J. of Mat. Sc. 15: 103-113.

Liu, C.C. & Huang, J.L. 2003. Effect of the electrical discharge machining on strength and reliability of TiN/Si3N4 composites. Ceram. Inter 29: 679-687.

Mazerolles, L., Feldhoff, A., Trichet, M. F. & Ricoult, M.B. 2005. Oxidation behaviour of Si3N4-TiN ceramics under dry and humid air at high temperature. J. of the Eur. Ceram. Soc 25: 1743-1748.

Messier, D.R., Riley, F.L. & Brook, R. J. 1978. The α/ß silicon nitride phase transformation, J. of Mat. Sc. 13: 1199-1205.

Niihara, K., Morena, R. & Hasselman, D.P.H. 1982, Evaluation of KIC of brittle solids by the indentation method with low crack-to-indent ratios. J. Mater Sc. Letter 1: 13-16.

Norhayati Ahmad, Obara, K., Sameshima, S. & Sueyoshi, H. 2009. Characterization of Si3N4 –TiN composites prepared by spark plasma sintering, trans. Mater. Res. Soc. Japan 32(4): 793-797.

Norhayati Ahmad & Sueyoshi, H. 2010. Properties of Si3N4 –TiN Composites Fabricated by Spark Plasma Sintering by Using a Mixture of Si3N4 and Ti Powders. Ceram. Int. 36: 491-496.

Norhayati Ahmad & Sueyoshi, H. 2011. Microstructure and mechanical properties of silicon nitride-titanium mitride composites prepared by spark plasma sintering. Materials Research Bulletin 46: 460-63.

Perera, D.S., Tokita, M. & Moricca, S. 1998. Comparative study of fabrication of Si3N4/SiC composites by spark plasma sintering and hot isostatic pressing. J. Eur. Ceram. Soc. 18: 401-404.

Salehi, S., Biest, O.V. & Vleugels, J. 2006. Electrically conductive ZrO2-TiN composites. J. of the Eur. Ceram. Soc. 26. 3173-3179.

Tokita, M. 1993. Mechanism of spark plasma sintering. J. Soc. Powder Tech. Jpn. 30(11): 790-804.

Wang, L., Wu, T., Jiang, W., Li, J. & Chen, L. 2006. Consolidation of nano-sized TiN powders by spark plasma sintering. J. Am. Ceram. Soc. 89(5): 1540-1543.

Weiss, J. & Kaysser, W.A. 1983. Liquid phase sintering in. In: (ed.), Progress in Nitrogen Ceramics, F.L. Riley (ed.) Boston: Martinus Nijhoff Publishers pp. 169.

*Corresponding author;  email: nhayati@fkm.utm.my