Enhancement of the densification and mechanical properties of aluminum-doped zinc oxide ceramics by hot isostatic pressing

The characteristics of sputtering targets used for transparent conductive oxide (TCO) films significantly affect the performances of TCO films produced by sputtering. The purpose of this study was to investigate the effect of hot isostatic pressing (HIP) on the densification, microstructure, electrical properties, and mechanical properties of Al-doped ZnO (AZO) and ZnO ceramic targets. The results showed that HIP treatment obviously improves the relative density, hardness, transverse rupture strength (TRS), and resistivity of AZO ceramics. AZO ceramics with relative densities of higher than 99.9% can be obtained after HIP at 1000 degrees C or 1250 degrees C. After HIP at 1250 degrees C, the resistivities of AZO ceramics are reduced from 6.0 x 10(-2) +/- 1.1 x 10(-2) Omega cm to 6.4 x 10(-4) +/- 2.9 x 10(-4) Omega cm. Furthermore, the hardness and TRS of AZO ceramics are raised from HV 261 +/- 6 to HV 322 +/- 5 and from 118 +/- 3 MPa to 260 +/- 3 MPa, respectively, after 1250 degrees C HIP. In contrast, for ZnO ceramics, the HIP process does not enhance the relative density or hardness, though the TRS and resistivity are improved. (C) 2015 Elsevier B.V. All rights reserved.