Indirect Measurement of Energy Density of Soft PZT Ceramic Utilizing Mechanical Stress

This paper reports on an indirect measurement of energy density of soft PZT ceramic utilizing mechanical stress. The method works analogous to the Olsen cycle and allows for a large amount of electro-mechanical energy conversion. A maximum energy density of 350 kJ/m³/cycle was found under 0–312 MPa and 1–20 kV/cm of applied mechanical stress and electric field, respectively. The obtained result is substantially higher than the results reported in previous studies of PZT materials utilizing a direct piezoelectric effect.     

Effect of KCl on the bulk growth KDP crystals by Sankaranarayanan-Ramasamy method

The effect of the addition of potassium chloride (KCl) in bulk growth unidirectional 〈0 0 1〉 potassium dihydrogen phosphate (KDP) grown from aqueous solution by Sankaranarayanan-Ramasamy (SR) method has been studied. The crystal of 15 mm diameter, 95 mm height was grown by SR method. Addition of 5 M% KCl in the bulk growth medium increases the quality as well as the growth rate. The grown crystals were characterized by UV–Vis spectroscopy, microhardness and dielectric studies. It reveals that the SR method grown crystalline quality and perfection is better than the conventional method grown crystal.     

Investigation of SR method grown 0 0 1 directed KDP single crystal and its characterization by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, optical and hardness studies

0 0 1 directed potassium dihydrogen orthophosphate (KDP) single crystal was grown by Sankaranarayanan–Ramasamy (SR) method. The 0 0 1 oriented seed crystals were mounted at the bottom of the platform and the size of the crystals were 10 mm diameter, 110 mm height. Two different growths were tried, in one the crystal diameter was the ampoule's inner diameter and in the other the crystal thickness was less than the ampoule diameter. In the first case only the top four pyramidal faces were existing whereas in the second case the top four pyramidal faces and four prismatic faces were existing through out the growth. The crystals were grown using same stoichiometric solution. The results of the two growths are discussed in this paper. The grown crystals were characterized by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, UV–vis spectroscopy and microhardness studies. The HRXRD analysis indicates that the crystalline perfection is excellent without having any very low angle internal structural grain boundaries. Laser damage threshold value has been determined using Nd:glass laser operating at 1054 nm. The damage threshold for the KDP crystal is greater than 4.55 GW cm⁻². The dielectric constant was higher and the dielectric loss was less in SR method grown crystal as against conventional method grown crystal. In thermal analysis, the starting of decomposition nature is similar in SR method grown KDP crystal and conventional method grown crystal. The SR method grown KDP has higher transmittance and higher hardness value compared to conventional method grown crystals.     

Estimation of energy density of PMN-PT ceramics utilizing mechanical stress

Abstract

Present study introduces an indirect measurement of energy density of (1-x)Pb(Mg_1/3Nb_2/3)O₃-(x)PbTiO₃ (PMN-PT) ceramics under compressive stress and electric field. The method works analogous to Olsen cycle which is a demonstration of a novel cycle converting mechanical energy into electrical energy. A large amount of electro-mechanical energy conversion can be achieved via this method. The ceramics were investigated under 0–75?MPa and 1–15?kV/cm of applied mechanical stress and electric field, respectively. A maximum energy density of 68?kJ/m³/cycle was achieved in 0.7PMN-0.3PT ceramic. The obtained result is significantly greater than that of linear piezoelectric phenomena.