Preparation And Energy’s Conversion Characteristic Of PZT-PZN-PNN Piezoelectric Ceramics

In recent years, piezoelectric energy harvesting technology is facing an obstacle to improve theefficiency of generating more electric energy for the devices. As the core component of the generators,piezoelectric materials have received considerable attention to discover a material system with highd33g33value, because a high d33g33value system indicates high energy density. However, theordinary PZT cannot meet the demand because the relationship between d33and g33is contradictory.Pb(Zr,Ti)O3–Pb(Zn1/3Nb2/3)O3–Pb(Ni1/3Nb2/3)O3(PZT–PZN–PNN) piezoelectric ceramic system hadreceived great attention since it was proposed due to its excellent properties. Focusing on therequirement of energy harvesting device, systematical compositions of PZT-PZN-PNN samples wereinvestigated by phase structure, microtopography, electric properties as well as energy conversion.Firstly, the effect of sintering temperature on the properties of xPZT–yPZN–(1–x–y)PNN arediscussed. To0.8PZT–0.1PZN–0.1PNN, for example, the content of tetragonal phase is increasingwith the sintering temperature growing from1000℃to1250℃, but obvious performance degradationwere observed as the impurities detected in the XRD patterns from the samples sintered in hightemperature. The optimum properties are obtained when the sintering temperature is1150℃:dT33=540pC/N， ε33/ε0=1692， kp=0.56， tanδ=0.0224， ρ=7.80g/cm3. In addition, the sinteringtemperature should be increase appropriately with the increase content of PZT or PZN.In order to understand the role of each component in the system, we defined the approximatelyregion of morphotropic phase boundary (MPB) on the ternary phase diagram from the XRD patterns.Two very high d33g33coefficients of20162.2×10-15m2/N and21026.3×10-15m2/N are observed fromsamples0.75PZT-0.15PZN-0.1PNN and0.8PZT-0.05PZN-0.15PNN with compositions located on therhombohedral phase side near MPB because the dielectric coefficient εT33/ε0decreases faster than thed33coefficient at this side.Lastly, unimorph cantilevers were made by0.8PZT-0.05PZN-0.15PNN and some common stylepiezoelectric ceramics. Then test their output voltage and calculate their power. To compare theiroutput voltage and calculated output power tested under the same condition, we find that the0.8PZT-0.05PZN-0.15PNN unimorph cantilever has the highest output power of0.77mW because ithas the highest d33g33coefficient. And the output power is large enough to supply the low-powerapplication...