Abstract
Shock synthesis of nanocrystalline Si was accomplished for the first time using thermal spray in which Si powder is injected into a high-energy flame where the particles melt and accelerate to impact on the substrate. A stream of molten Si particles impacted onto Si wafers of two orientations (100) and (111). The shock wave generated by the sudden impact of the droplets propagated through the underlying Si layer, which experienced a phase transition to a high-pressure form of Si due to propagation of the shock wave. The metastable high-pressure form of Si then transformed to metastable Si-IX, Si-IV (hexagonal diamond-Si), R-8, and BC-8 phases as evidenced by transmission electron microscopy and x-ray diffraction studies. Back-transformed metastable Si grains, with a size range from 2 to 5 nm, were found to be dispersed within Si-I (cubic diamond-Si). The metastable phases formed mostly in deposits on the (100) substrate compared to those of the (111) substrate orientations. This behavior can be correlated with the anisotropic nature of the pressure-induced transformations of Si-I.
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References
D. Tabor, The Hardness of Metals (Oxford, London, 1951).
J.B. Pethica, R. Hutchings, and W.C. Oliver, Phil. Mag. A48, 593 (1983).
D. Stone, W.R. LaFontaine, P. Alexopoulos, T.W. Wu, and C-Y. Li, J. Mater. Res. 3, 141 (1988).
M.F. Doener and W.D. Nix, J. Mater. Res. 1, 601 (1986).
W.C. Oliver and G.M. Pharr, J. Mater. Res. 7, 1564 (1992).
Y-T. Cheng and C-M. Cheng, Appl. Phys. Lett. 73, 614 (1998).
A.K. Bhattacharya, and W.D. Nix, Int. J. Solids Structures 24, 881 (1988).
T.A. Laursen, and J.C. Simo, J. Mater. Res. 7, 618 (1992).
S.M. Myers, J.A. Knapp, D.M. Follstaedt. and M.T. Dugger, J. Appl. Phys. 83, 1256 (1998).
Y-T. Cheng and C-M. Cheng, Int. J. Solids Structures 36, 1231 (1999).
Y-T. Cheng and C-M. Cheng, J. Appl. Phys. 84, 1284 (1998).
J. Lubliner, Plasticity Theory (Macmillan, New York, 1990).
G. Dieter, Mechanical Metallurgy, Second Edition (McGraw-Hill, New York, 1976).
ABAQUS, version 5.6 and 5.7, Hibbitt, Karlsson & Sorensen, Inc. (Pawtucket, RI 02860, USA).
Y-T. Cheng and C-M. Cheng, Mag. Lett. 77, 39 (1998).
J.L. Loubet, J.M. Georges, O. Marchesini, and G. Meille, Trans. Am. Soc. Mech. Eng.: J. Tribology 106, 43 (1984).
M. Lichinchi, C. Lenardi, J. Haupt, and R. Vitali, Thin Solid Films 312, 240 (1998).
Y-T. Cheng and C-M. Cheng, J. Mater. Res. 13, 1059 (1998).
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Goswami, R., Sampath, S., Herman, H. et al. Shock synthesis of nanocrystalline Si by thermal spraying. Journal of Materials Research 14, 3489–3492 (1999). https://doi.org/10.1557/JMR.1999.0471
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DOI: https://doi.org/10.1557/JMR.1999.0471