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High Q m values and humidity effect on the electrical properties of (K, Na)NbO 3 lead‐free piezoceramics doped with B 2 O 3 –CuO mixed oxides
Author(s) -
Zhen Yuhua,
Li Linling,
Lin Yaning,
Wang Ke,
Zhu Fangyuan,
Jia Kaili
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14586
Subject(s) - natural bond orbital , relative humidity , microstructure , ceramic , materials science , humidity , analytical chemistry (journal) , doping , dielectric , mineralogy , composite material , chemistry , thermodynamics , physics , density functional theory , computational chemistry , optoelectronics , chromatography
To greatly enhance the mechanical quality factor ( Q m ) of piezoceramic materials, B 2 O 3 –CuO mixed oxides were added to a K 0.48 Na 0.52 NbO 3 ‐based lead‐free piezoceramic (abbreviated as BC ‐ KNN ). The results suggest that the B 2 O 3 –CuO additives effectively improved the sinterability and Q m value of the piezoceramic. An optimal Q m value as high as 2128 was obtained, which is 35 times higher than that of pure KNN ceramic. Interestingly, we found that the Q m value was sensitive to humidity of the surrounding environment. As the relative humidity ( RH ) increased from 25% RH to 78% RH , the Q m value of the BC ‐ KNN ceramics decreased from 2128 to 267. We found that the dependence of the Q m value on humidity was closely related to the instability of the relative dielectric constant (ɛ r ). Our results show that a dense microstructure is critical for maintaining a stable high Q m performance in a humid environment.