Effect of Grain Size on Mechanical Properties of Full-Dense Pb(Zr,Ti)O3 Ceramics

概要

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The grain size dependence of mechanical properties was investigated in full-dense Pb(Zr,Ti)O3 (PZT) ceramics using a microindentation fracture method. Full-dense PZT ceramics with an average grain size ranging from 0.09 to 2.3 μm were successfully prepared by a novel compaction method based on aerosol deposition (AD). Vickers hardness ($H_{\text{v}}$) increased with decreasing grain size and the Hall–Petch relationship ($H_{\text{v}}=H_{\text{v0}}+kd^{-1/2}$) was confirmed over almost the entire grain size range investigated, which indicates that grain size could be the determining factor of hardness in full-dense PZT ceramics. On the other hand, fracture toughness ($K_{\text{C}}$) decreased with decreasing grain size below the critical grain size of 1.0 μm. The critical grain size was consistent with that below which the volume fraction of the tetragonal phase ($V_{\text{Tet}}$) decreased with decreasing grain size, which indicates that ferroelastic 90° domain switching is a viable toughening mechanism in PZT ceramics. In this study, we have demonstrated that, with suitable microstructural control, the PZT ceramics with ultra-high strength for contact situations can be realized without any sacrifice in piezoelectric properties.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2010-09-25