Surface modification of barium titanate particles has been carried out using a wet chemical method.The microstructural and dielectric properties of the ceramics made from surface modified particles were extensively investigated by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and dielectric properties measurements.The breakdown strength increased by 69%and 117%for the Al_(2)O_(3) and B_(2)O_(3)–SiO_(2) modified ceramics,respectively.An energy storage density of up to 3.2 J/cm^(3) has been obtained.The suppression of grain boundary electron transport and reduction in pore defects lead to the energy storage properties enhancement of the modified ceramics.These results indicated that surface modification of ceramic particles is a promising approach to obtain dielectric ceramics with high energy storage density.
There are a large number of research publications on the hot topic of environmental friendly leadfree piezoelectric materials worldwide in the last decade.The number of researchers and institutions involved from China is much larger than other countries or regions.The publications by Chinese researchers cover a broad spectrum on the preparations,structures,properties and applications of lead-free piezoelectric ceramics.This has motivated us to come out with a review on recent advances in development of lead-free piezoelectric ceramics in China.The emphases are especially on the preparation and electric properties of barium titanate-based materials,bismuth sodium titanate and related materials,alkaline niobate and related materials,bismuth layerstructured materials,as well as texture engineering of ceramics and some of their single crystals.Hopefully,this could give further impetus to the researchers to continue their e®orts in this promising area and also draw the attentions from legislature,research o±ce,industrial and publics.
