Low-temperature sintering of MnO{sub}2-doped PZT-PZN Piezoelectric ceramics

摘要

The effect of MnO{sub}2 addition on the micro-structural evolution and piezoelectric properties of low temperature sinterable PZT-PZN ceramics was investigated. When a small amount of MnO{sub}2 (<0.5 wt% ) was added, the Mn ions were homogeneously dissolved in the PZT-PZN ceramics, leading to full densification at a temperature as low as 930℃. However, the further addition of MnO{sub}2 hindered the densification, causing the specimen to have a high porosity and small grain size. In addition, as the MnO{sub}2 content increased, the crystal structure of the PZT-PZN changed gradually from a tetragonal to a rhombohedral phase, due to the substitution of Mn for the B-sites in the perovskite structure. The addition of MnO{sub}2 up to a maximum of 0.5% improved the mechanical quality factor (2m) of the PZT-PZN ceramics markedly, while keeping the k{sub}p and d{sub}33 values reasonably high. The 80% PZT-20% PZN doped with 0.4 wt% MnO{sub}2 exhibited excellent piezoelectric properties; Q{sub}m= 1,000, k{sub}p=0.62, and d{sub}33 = 330 pC/N.