TY  - EJOU
AU  - Chen, Pan 
AU  - Chu, Baojin 

TI  - Size	Dependent	Structures	and	Properties	of	Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub>-Based	 Ceramics	for	Piezoelectric	Sensors
T2  - The International Conference on Computational \& Experimental Engineering and Sciences

PY  - 2023
VL  - 26
IS  - 4
SN  - 1933-2815

AB  - Generally,	 film	dielectric	materials	often	exhibit	size-dependent	structure	and	electric	properties.	 In	 this	
work,	 we	 demonstrate	 a	 similar	 behavior	 in	 bulk	 Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub> (NBT)-based	 polycrystalline	 ceramics.
According	to	the	results	from	X-ray	diffraction,	the	(Na<sub>0.5</sub>Bi<sub>0.5</sub>)<sub>0.92</sub>Ba<sub>0.08</sub>Ti<sub>0.99</sub>Mg<sub>0.01</sub>O<sub>2.99</sub> (NBT8M1.0)	ceramic	
showed	a	complex	structure	 that	consists	of	rhombohedral,	 tetragonal	and	cubic	symmetries. We	 found,	
when decreasing	 the	 thickness	of	a	<i>ϕ</i> 10	mm	NBT8M1.0	ceramic	 from	1230	μm	 to	230	μm,	 the	ceramic	
showed	increased	content	of	cubic	symmetry	(CC)	from	28%	to	56%.	Meanwhile,	the	piezoelectric	response	
(<i>d<sub>33)</sub></i>	increased	from	107	pC/N	to	134	pC/N	and	the	depolarization	temperature	(<i>T<sub>d</sub></i>)	decreased	from	170	℃
to	142	℃.	Similarly,	when	decreasing	the	diameter	of	a	1	mm	thick	NBT8M1.0	ceramic	from	<i>ϕ</i> 22	mm	to	<i>ϕ</i> 6
mm,	the	ceramic	showed	increased	CC	from	18%	to	44%. Meanwhile,	the	d33	increased	from	125	pC/N	to	
135	pC/N	and the	<i>T<sub>d</sub></i> decreased	from	165	℃ to	156	℃. The	origin	of	size-dependent	structure	and	properties	
in	macroscopic	size	range	of	NBT8M1.0	ceramics	were	further	studied	by	investigating	the	difference	of	the	
size-dependence	 between	 the	 ceramics	 sintered	 from	 green	 bodies	 prepared	 by	 uniaxial	 pressing	 and	
isostatic	pressing.	The	results	demonstrated	that	the	size-dependent	structure	and	properties	of	NBT-based	
polycrystalline	ceramics	are	closely	 related	 to	 the	 residual	 stress	 from	 the	inhomogeneous	densification during	sintering	process,	as	a	result	of	the	inhomogeneous	density	distribution	in	the	pressed	green	body.
KW  - Size-dependence;	piezoelectric	ceramics;	Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub>;	inhomogeneous	densification

DO  - 10.32604/icces.2023.09199