K C. Goretta et al. Materials Science and Engineering A 412(2005)146-152 understanding attributable to their efforts We thank dr. jc McNulty for his excellent studies of fracture and for provid ing some of the photomicrographs that appear in this paper 13.3 um This work was supported by the Defense Advanced Research Projects Agency through an Interagency Agreement with the U.S. Department of Energy(DOE), and by doE itself, under Contract W-31-10 38, by North Atlantic Treaty Orga 1.0m zation Grant PSTCLG.977016, by the Russian Academy of Sciences; by the Ministerio de Educacion y Ciencias of Spain, 1.3 mm under CICYT Project MAT2000-1533-C03-03 Fig. 7. Profilometer scan of polished Si3N4/BN surface; removal of BN cell boundary is evident. References long-term frictional response. The linear sliding velocity was [1] w.S. Coblenz, U.S. Patent 4, 772, 524(1988) 0. I m/s and the relative humidity of the test environment was [2] D. Popovic, J.W. Halloran, G.E. Hilmas, G.A. Brady, S. Somas, A Bard, G. Zywicki, U.S. Patent 5, 645, 781(1997) 3]S. Baskaran, S. Nunn, D. Popovich, J.W. Halloran, J. Am. Ceram Soc. For Si3N4 balls sliding against dry Si3N4 and FM fats, fric- tion coefficients were 0.6-0.8. BN lubricant sprayed onto the [4]D Popovic, S Baskaran, G. Zywicki, C Arens, J.W. Halloran, Ceram FM flats produced modest reductions in friction coefficients Trans.42(1994)173-186 For lubricated sliding, friction coefficients for the Si3N4 flats [5]G. Hilmas, A. Brady, J.W. Halloran, Ceram.Trans.51(1995)609- were 0.05-0.15 and for the Fms were 0.01--0.08. The signif- icantly lower coefficients of friction for the FM were probably G. Hilmas, A Brady, U. Abdali, G. Zywicki, J.w. Halloran, Mater. Sci were due to removal of some of the BN cell-boundary mate- [7 D. Kovar, B.H. King, RW.Trice,W.Halloran,J.Am.CeramSoc al, leaving long grooves, typically 6-8 um deep, on the sliding 80(1997)2471-2487 surface (Fig. 7). These grooves likely acted as reservoirs to 8]Sw. Lee, D K. Kim, Ceram. Eng. Sci. Proc. 18(4)(1997)481-486 retain and distribute lubricant, and to trap wear debris. The [9] Advanced Ceramics Research, 3292 East Hemisphere Loop, Tucson, AZ average wear rates of Si3N4 balls were x10-mm'N-Im-I 85705-5013,USA 10]ZZ Fang, A. Griffo, B. White, G. Lockwood, D. Belnap, G. Hilmas, for dry sliding and A10-8 to 10-7mm- for lubri- J. Bitler, Int. J. Ref Met. Hard Mater. 19(2001)453-458 cated sliding. The average specific wear rates of balls were of [11] J.L. Finch, J.M. Staehler, L P. Zawada, W.A. Ellingson, J.G. Sun, CM the same order as those measured with sliding on conventional emer, Ceram. Eng. Sci. Proc. 20(3)(1999)341-351 12].W. Trice, J.W. Halloran, J. Am. Ceram. Soc. 82(1999)2563- [13]RW.Trice, J.w. Halloran, J. Am. Ceram. Soc. 82(1999)2502-2508 4. Summary and assessment [14]SY. Lienard, D. Kovar, R.J. Moon, K.J. Bowm Mater.Sci.53(2000)3365-3371. Manufacture of Si3N4/Bn FMs and their resulting [15]RW Trice, J.W. Halloran, J. Am. Ceram. Soc. 83(2000)311-316 [16]M. Tlustochowitz, D. Singh, W.A. Ellingson, K.C. Goretta, M. Rigali, microstructures have been summarized. Measurements and M. Sutaria, Ceram. Trans. 103(2000)245-254. modeling of various mechanical properties were discussed; elas- [17 D. Singh, T.A. Cruse, D.J. Hermanson, K.C. Goretta, E.W. Zok, JC tic constants, thermal expansion, flexural failure, shear failure, McNulty, Ceram. Eng. Sci. Proc. 21(3)(2000)597-604 n-plane stresses and failure, toughening mechanisms, creep, and [18 J.C. MeNulty, M.R. Begley, F.W. Zok, J. Am. Ceram. Soc. 84(2001) tribological properties. Si3N4/BN FM laminates are relatively [19)B. 1. Smirnov, Y.A. Burenkov, B.K. Kardashev, D. Singh, K.C.Goretta, strong and stiff, very tough in flexure, and resistant to creep and A R de Arellano-Lopez, Phys. Solid State 43(2001)2094-2098. sliding wear. They exhibit, however, poor resistance to impact [20] D. Singh, K.C. Goretta, J W. Richardson Jr, A. de Arellano-lopez, by hard solid particles and are susceptible to oxidation at high Scripta Mater. 46(2002)747-751 temperatures. For use of Si3N4/BN FMs at high temperatures, [21] M.Y. He, D. Singh, J.C. McNulty, F.W. Zok, Comp. Sci. Technol. 62 either service times must be short or a highly effective environ- (2002)967-976 [22].N. Cox, F.W. Zok, Curr Opin. Solid State Sci. Mater. Sci. 1(1996) mental barrier must be applied The modest pullout of cells during fracture (pullout [23]NS Jacobson, E.J. Opila, K.N. Lee, Curr. Opin. Solid State Mater.Sci length 100 um) limits the toughness of Si3 N4/BN FMs. Bet- 5(2001)301-309 ter manufacturing, in which distortion of the cells along their [24] K.C. Goretta, et al. ANL-01/04: Development of Advanced Fibrous lengths is limited, should promote longer pullout lengths and Monoliths-Final Report for Project of 1998-2000, Argonne National [26]AG. Cooper, S. Kang, J w. Kietzman, F.B. Prinz, J. L. Lombardi, L.E. Weiss, Mater. Des. 20(1999)83-89 Acknowledgments 227].D. Cawley, Curr. Opin. Solid State Mater. Sci. 4(1999)483- [28]Jw. Halloran, Brit Ceram. Proc. 59(199K.C. Goretta et al. / Materials Science and Engineering A 412 (2005) 146–152 151 Fig. 7. Profilometer scan of polished Si3N4/BN surface; removal of BN cell boundary is evident. long-term frictional response. The linear sliding velocity was 0.1 m/s and the relative humidity of the test environment was ≈40%. For Si3N4 balls sliding against dry Si3N4 and FM flats, fric￾tion coefficients were 0.6–0.8. BN lubricant sprayed onto the FM flats produced modest reductions in friction coefficients. For lubricated sliding, friction coefficients for the Si3N4 flats were ≈0.05–0.15 and for the FMs were 0.01–0.08. The signif￾icantly lower coefficients of friction for the FM were probably were due to removal of some of the BN cell-boundary mate￾rial, leaving long grooves, typically 6–8
m deep, on the sliding surface (Fig. 7). These grooves likely acted as reservoirs to retain and distribute lubricant, and to trap wear debris. The average wear rates of Si3N4 balls were ≈10−5 mm3 N−1 m−1 for dry sliding and ≈10−8 to 10−7 mm3 N−1 m−1 for lubri￾cated sliding. The average specific wear rates of balls were of the same order as those measured with sliding on conventional Si3N4. 4. Summary and assessment Manufacture of Si3N4/BN FMs and their resulting microstructures have been summarized. Measurements and modeling of various mechanical properties were discussed: elas￾tic constants, thermal expansion, flexural failure, shear failure, in-plane stresses and failure, toughening mechanisms, creep, and tribological properties. Si3N4/BN FM laminates are relatively strong and stiff, very tough in flexure, and resistant to creep and sliding wear. They exhibit, however, poor resistance to impact by hard solid particles and are susceptible to oxidation at high temperatures. For use of Si3N4/BN FMs at high temperatures, either service times must be short or a highly effective environ￾mental barrier must be applied. The modest pullout of cells during fracture (pullout length ∼ 100
m) limits the toughness of Si3N4/BN FMs. Bet￾ter manufacturing, in which distortion of the cells along their lengths is limited, should promote longer pullout lengths and improved properties. Acknowledgments We thank our colleagues Prof. F.W. Zok and Dr. W.A. Elling￾son for many helpful discussions and for the knowledge and understanding attributable to their efforts. We thank Dr. J.C. McNulty for his excellent studies of fracture and for provid￾ing some of the photomicrographs that appear in this paper. This work was supported by the Defense Advanced Research Projects Agency through an Interagency Agreement with the U.S. Department of Energy (DOE), and by DOE itself, under Contract W-31-109-Eng-38; by North Atlantic Treaty Organi￾zation Grant PST.CLG.977016; by the Russian Academy of Sciences; by the Ministerio de Educacion y Ciencias of Spain, ´ under CICYT Project MAT2000-1533-C03-03. References [1] W.S. Coblenz, U.S. Patent 4,772,524 (1988). [2] D. Popovic’, J.W. Halloran, G.E. Hilmas, G.A. Brady, S. Somas, A. Bard, G. Zywicki, U.S. Patent 5,645,781 (1997). [3] S. Baskaran, S. Nunn, D. Popovich, J.W. Halloran, J. Am. Ceram. Soc. 76 (1993) 2209–2216. [4] D. Popovic’, S. Baskaran, G. Zywicki, C. Arens, J.W. Halloran, Ceram. Trans. 42 (1994) 173–186. [5] G. Hilmas, A. Brady, J.W. Halloran, Ceram. Trans. 51 (1995) 609– 614. [6] G. Hilmas, A. Brady, U. Abdali, G. Zywicki, J.W. Halloran, Mater. Sci. Eng. 195A (1995) 263–268. [7] D. Kovar, B.H. King, R.W. Trice, J.W. Halloran, J. Am. Ceram. Soc. 80 (1997) 2471–2487. [8] S.W. Lee, D.K. Kim, Ceram. Eng. Sci. Proc. 18 (4) (1997) 481–486. [9] Advanced Ceramics Research, 3292 East Hemisphere Loop, Tucson, AZ 85705-5013, USA. [10] Z.Z. Fang, A. Griffo, B. White, G. Lockwood, D. Belnap, G. Hilmas, J. Bitler, Int. J. Ref. Met. Hard Mater. 19 (2001) 453–458. [11] J.L. Finch, J.M. Staehler, L.P. Zawada, W.A. Ellingson, J.G. Sun, C.M. Deemer, Ceram. Eng. Sci. Proc. 20 (3) (1999) 341–351. [12] R.W. Trice, J.W. Halloran, J. Am. Ceram. Soc. 82 (1999) 2563– 2565. [13] R.W. Trice, J.W. Halloran, J. Am. Ceram. Soc. 82 (1999) 2502–2508. [14] S.Y. Lienard, D. Kovar, R.J. Moon, K.J. Bowman, J.W. Halloran, J. Mater. Sci. 53 (2000) 3365–3371. [15] R.W. Trice, J.W. Halloran, J. Am. Ceram. Soc. 83 (2000) 311–316. [16] M. Tlustochowitz, D. Singh, W.A. Ellingson, K.C. Goretta, M. Rigali, M. Sutaria, Ceram. Trans. 103 (2000) 245–254. [17] D. Singh, T.A. Cruse, D.J. Hermanson, K.C. Goretta, F.W. Zok, J.C. McNulty, Ceram. Eng. Sci. Proc. 21 (3) (2000) 597–604. [18] J.C. McNulty, M.R. Begley, F.W. Zok, J. Am. Ceram. Soc. 84 (2001) 367–375. [19] B.I. Smirnov, Y.A. Burenkov, B.K. Kardashev, D. Singh, K.C. Goretta, A.R. de Arellano-Lopez, Phys. Solid State 43 (2001) 2094–2098. [20] D. Singh, K.C. Goretta, J.W. Richardson Jr., A. de Arellano-Lopez, Scripta Mater. 46 (2002) 747–751. [21] M.Y. He, D. Singh, J.C. McNulty, F.W. Zok, Comp. Sci. Technol. 62 (2002) 967–976. [22] B.N. Cox, F.W. Zok, Curr. Opin. Solid State Sci. Mater. Sci. 1 (1996) 666–673. [23] N.S. Jacobson, E.J. Opila, K.N. Lee, Curr. Opin. Solid State Mater. Sci. 5 (2001) 301–309. [24] K.C. Goretta, et al. ANL-01/04: Development of Advanced Fibrous Monoliths—Final Report for Project of 1998–2000, Argonne National Laboratory, 2001. [26] A.G. Cooper, S. Kang, J.W. Kietzman, F.B. Prinz, J.L. Lombardi, L.E. Weiss, Mater. Des. 20 (1999) 83–89. [27] J.D. Cawley, Curr. Opin. Solid State Mater. Sci. 4 (1999) 483– 489. [28] J.W. Halloran, Brit. Ceram. Proc. 59 (1999) 17–28 (as cited in Ref. [7]). [29] Y.-H. Koh, H.W. Kim, H.E. Kim, J.W. Halloran, J. Am. Ceram. Soc. 85 (2002) 3123–3125