M. Hadad et al./ Wear 260(2006)634-641 Fig 8. SEM micrographs of wom surfaces morphology at 300.C:(a)Si3N4 bulk and (b)Si3N4-30% TiN composite 4. Conclusion 3]Y. Zhou, Mechanical properties and toughening mechanisms of The addition of up to 30% of titanium nitride to silicon nitride matrix led to an improvement of wear resistance of 4]J. Huang, Y.L. Chang, H.H. Lu, Fabrication of multi-laminated SigN4-Si3 N4/TiN composites and its anisotropic fracture behaviour, composites of up to three times, which has been attributed to ariations of residual stresses at the scale of the grain size due [5]A. Tarlazzi, et al., Tribological behaviour of Al2O3/ZrO2-ZrO2 lam- to the mismatch of thermal expansion coefficient between inated composites, Wear 244(2000)29-40 Si3N4 and tiN. Concerning laminate material, sliding on transversal orientation shows the highest wear resistance (7) B.-T. Lee, Y.J. Yoon, K-H. Lee, Microstructural characterization among all orientations. Comparing the different laminates of electroconductive Si3N4-TIN composites, Mater. Lett. 47(2001) laminates 30 shows the highest wear resistance On the other 71-76 hand,comparing laminates to composites, laminate struc- [8]A. Bellosi, A. Fiegna, A Giachello, Microstructure and Properties ture with additional stresses between layers that leads to of Electrically Conductive Si3N4-TIN Composites, Elsevier Science Publishers B V, 1991, pp 225-234 an increase macroscopic fracture toughness did not improve [9]HJ. Choi,K-S. Cho, J-G. Lee, R-curve behaviour of silicon wear resistance compared to Si3N4-%TIN composites. This tride- titanium nitride composites, J. Am. Ceram. Soc. 80(1997) is because wear is produced by mechanical contact, and sub- 2681-2684. sequent particle detachment that takes place at the micrometer [10] J.-L. Huang, S-Y. Chen, Investigation of silicon nitride composites and submicrometer scale. At 300oC. the wear resistance of toughened with prenitrided TiB2 21(1995)77-83 Si3N4-30% TIN composites still was two times greater than [11C -H. Yeh, M.-H. Hon, The SiN by slip casting, Cer SiaNa bulk [12]C. Wang, Control of composition ture in laminated sili- con nitride/boron nitride composites, J. Am. Ceram Soc. 85(2002) 2457-2461 [13]J.-L. Huang, F-C. Chou, H -H. Lu, Investigation of Acknowledgement Si3N4-TiNSi3N4-Si3N4 trilayer composites with residual surface compression, J. Mater. Res. 12(9)(1997)2357-2365 We would like to thank the gebert -Ruf Foundation [14 M.F. Amateau, Performance of laminated ceramic composite cutting Switzerland for the support under project VERBUNDLOTE [15]J.A. Hawk, DA(1995)317- Alman, J.J. Petrovic, Abrasive wear of (No. 1125.045)as well as the European Commission and SigNa-MoSi2 composites, Wear 203-204(1997)247-256 Swiss BBW under FP5 INCO Project LAMINATES(ICA- [16]MN. Gardos, R.G. Hardisty, Fracture ess-and hardness. CT-2000-10020; BBW contract 99.0785) ceramIcs. In 36(1993)652-660. [17E. Rabinowicz, Friction and Wear of Materials, second ed, A. wiley nescience Publication, 1995. [18]S.-T.Buljan, S.E. Wayne, Wear and design of ceramic cutting tool References [19S.F. Wayne, Microstructural aspects of Si3N4-TiC composites affect- [X. Zhao, Tribological characteristics of Si3N4 ceramic sliding on ing abrasion and erosion resistance, Tribol. Trans. 45(1990) ainless steel, Wear 206(1997)76-82 2]X.Z. Zhao, et al., Wear behaviour of Si N4 ceramic cutting tool [20]A. Skopp, M. Woydt, K. Habig, Tribological behavior of sill- Ceram.Int.25(4)(1999)309315 1000°C, Wear I8l-183(1995)571-580.640 M. Hadad et al. / Wear 260 (2006) 634–641 Fig. 8. SEM micrographs of worn surfaces morphology at 300 ◦C: (a) Si3N4 bulk and (b) Si3N4–30% TiN composite. 4. Conclusion The addition of up to 30% of titanium nitride to silicon nitride matrix led to an improvement of wear resistance of composites of up to three times, which has been attributed to variations of residual stresses at the scale of the grain size due to the mismatch of thermal expansion coefficient between Si3N4 and TiN. Concerning laminate material, sliding on transversal orientation shows the highest wear resistance among all orientations. Comparing the different laminates, laminates 30 shows the highest wear resistance. On the other hand, comparing laminates to composites, laminate struc￾ture with additional stresses between layers that leads to an increase macroscopic fracture toughness did not improve wear resistance compared to Si3N4–%TiN composites. This is because wear is produced by mechanical contact, and sub￾sequent particle detachment that takes place at the micrometer and submicrometer scale. At 300 ◦C, the wear resistance of Si3N4–30% TiN composites still was two times greater than Si3N4 bulk. Acknowledgements We would like to thank the Gebert-Ruf Foundation, ¨ Switzerland for the support under project VERBUNDLOTE (No. 1125.045) as well as the European Commission and Swiss BBW under FP5 INCO Project LAMINATES (ICA￾CT-2000-10020; BBW contract 99.0785). References [1] X. Zhao, Tribological characteristics of Si3N4 ceramic sliding on stainless steel, Wear 206 (1997) 76–82. [2] X.Z. Zhao, et al., Wear behaviour of Si3N4 ceramic cutting tool material against stainless steel in dry and water-lubricated conditions, Ceram. Int. 25 (4) (1999) 309–315. [3] Y. Zhou, Mechanical properties and toughening mechanisms of Si3N4 matrix laminated ceramic composite, Key Eng. Mater. 161–163 (1999) 353–356. [4] J. Huang, Y.-L. Chang, H.H. Lu, Fabrication of multi-laminated Si3N4–Si3N4/TiN composites and its anisotropic fracture behaviour, J. Mater. Res. Soc. 12 (1997) 2337–2344. [5] A. Tarlazzi, et al., Tribological behaviour of Al2O3/ZrO2–ZrO2 lam￾inated composites, Wear 244 (2000) 29–40. [6] M. Woydt, Wear engineering oxides/anti-wear oxides, Wear 218 (1998) 84–95. [7] B.-T. Lee, Y.-J. Yoon, K.-H. Lee, Microstructural characterization of electroconductive Si3N4–TiN composites, Mater. Lett. 47 (2001) 71–76. [8] A. Bellosi, A. Fiegna, A. Giachello, Microstructure and Properties of Electrically Conductive Si3N4–TiN Composites, Elsevier Science Publishers B.V., 1991, pp. 225–234. [9] H.J. Choi, K.-S. Cho, J.-G. Lee, R-curve behaviour of silicon nitride-titanium nitride composites, J. Am. Ceram. Soc. 80 (1997) 2681–2684. [10] J.-L. Huang, S.-Y. Chen, Investigation of silicon nitride composites toughened with prenitrided TiB2, Ceram. Int. 21 (1995) 77–83. [11] C.-H. Yeh, M.-H. Hon, The Si3N4 and Si3N4/TiC layered composites by slip casting, Ceram. Int. 23 (1996) 361–366. [12] C. Wang, Control of composition and structure in laminated sili￾con nitride/boron nitride composites, J. Am. Ceram. Soc. 85 (2002) 2457–2461. [13] J.-L. Huang, F.-C. Chou, H.-H. Lu, Investigation of Si3N4–TiN/Si3N4–Si3N4 trilayer composites with residual surface compression, J. Mater. Res. 12 (9) (1997) 2357–2365. [14] M.F. Amateau, Performance of laminated ceramic composite cutting tools, Ceram. Int. 21 (1995) 317–323. [15] J.A. Hawk, D.E. Alman, J.J. Petrovic, Abrasive wear of Si3N4–MoSi2 composites, Wear 203–204 (1997) 247–256. [16] M.N. Gardos, R.G. Hardisty, Fracture toughness-and hardness￾dependent polishing wear of silicon nitride ceramics, Tribol. Trans. 36 (1993) 652–660. [17] E. Rabinowicz, Friction and Wear of Materials, second ed., A. Wiley￾Interscience Publication, 1995. [18] S.-T. Buljan, S.F. Wayne, Wear and design of ceramic cutting tool materials, Wear 133 (1989) 309–321. [19] S.F. Wayne, Microstructural aspects of Si3N4–TiC composites affect￾ing abrasion and erosion resistance, Tribol. Trans. 45 (1990) 553–558. [20] A. Skopp, M. Woydt, K. Habig, Tribological behavior of sili￾con nitride materials under unlubricated sliding between 22 ◦C and 1000 ◦C, Wear 181–183 (1995) 571–580