Journal of Inorganic Materials

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Microstructure and Nanoindentation Mechanical Properties of Detonation Sprayed Coatings Derived from Al2O3/TiO2 Nanocomposite Powders

ZHAI Chang-Sheng1; YANG Li2; WANG Jun1; ZHAO Wen-Ming1; SUN Bao-De1   

  1. 1。 State Key Laboratory of Metal Matrix Composites; Shanghai Jiaotong University; Shanghai 200030, China; 2. Shanghai Testing Center of Nanometer Materials; Shanghai 200237, China
  • Received:2004-11-01 Revised:2004-12-13 Published:2005-11-20 Online:2005-11-20

Abstract: This paper researched the microstructrue and nanoindentation mechanical properties of detonation sprayed coatings derived from Al2O3/TiO2 nanocomposite powders. The pores of the
nanocomposite coating (NCC) appeared to be generally equal-sized and showed a very homogeneous distribution, while the conventional microcomposite coating (MCC) appears an inhomogeneous pore
distribution. The results also indicate that NCC has better chimerism between splat interfaces than MCC and more homogeneous melting condition. A mass of grain boundaries, sub-boundaries and
nanosized microcracks in NCC lead the matrix Al2O3 to be nanoparticulate, while a mass of unmelted particles can be detected in MCC. Both of Al2O3/3wt%TiO2 nanocompsite and
conventional coatings exihibit apparently anisotropic nanoindentation mechanical behaviors, which are due to the anisotropic microstructure of the as-sprayed coatings. The mean values and distribution
intervals of both nanoindentation hardness and Young’s modulus of NCC are higher than those of corresponding surface and cross section of MCC. Therefore, NCC exhibits better nanoindentation
mechanical properties than MCC, which is due to the reinforcing effect of TiO2 nanoparticles on the matrix Al2O3 particles of NCC.

Key words: nanocomposite coating, detonation spray, microstructure, nanoindentation mechanical properties

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