• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1314-1316
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• 1997

In this study, We fabricated thin film magnetic core inductors by using thin film manufacturing techniques such as photolithography and wet etching process. The inductors were prepared using multi-layered CoNbZr/Cu/CoNbZr. These devices are measured at high frequency range of $1\;MHz{\sim}1\;GHz$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.2
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• pp.170-176
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• 1998

The team mixed PbO, $ZrO_2$, $TiO_2$, $Nb_2O_5$ and $MnCO_3$, to make $Pb[(Zr_{0.54}\;Ti_{0.46})\;Nb_{0.005}]O_3+4%MnCO_3$. The electroded PZT ceramics were poled by 3 kV/mm at $110^{\circ}C$ for 600 s. We assembled the 0.4mm thick PZT slices into ultrasonic transducers. Central frequency of the probe is 5 MHz, which is proper to the thickness gauge for steel pipes and for flaw detector. The probe can detect a disk shape defect of 1mm diameter at 15cm deep in steel block. The new probe's Fresnel zone that the ultrasonic beam do not broaden is 13mm. Over the Fresnel zone, the ultrasonic beam spreads. Half of the beam spread angle of the probe is $4.3^{\circ}-4.6^{\circ}$. This probe can be used for the ultrasonic transducers for non-destructive testing of steel bridges.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.04a
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• pp.60-61
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• 2002

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.11.1-11.1
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• 2008

• Journal of the Korean Ceramic Society
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• v.23 no.1
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• pp.60-66
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• 1986

The effect of composition size of sintered body and electrode on resonant characteristics of the system $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$ has been decribed. Composition ranged from X=40 to X=55 diameter of sintered body ranged from D=6.5 to D=12.5(mm) and diameter of electrode ranged from De=5.5 to De=11 (mm) In the composition of morphotropic phase boundary antiresonant frequency (fa) dcreased slowly whereas resonant frequency (fr) decreased rapidly on the ground of this Δf(fa-fr) and electromechanical coupling fractor Kp increased and Qm showed low value. On the contrary in toward the composition of tetragonal and rhombo-hedral fa increased slowly whereas fr increased rapidly on the ground of this Δf and Kp decreased and Qm increased abruptly. Substance of the above statements have no concern with size of sintered body and ele-ctrode. The other side as the size of electrode decreased Qm fr, fa and Δf increased. Cm and Co dominantly affect the resonant frequency and antiresonant frequency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.227-231
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• 2008

In this study, in order to improve the electrical properties of low temperature sintering piezoelectric ceramics, $[0.05Pb(Zn_{1/2}W_{1/2})-0.07Pb(Mn_{1/3}Nb_{2/3})-0.088Pb(Zr_{0.48}Ti_{0.52})]O_3$(abbreviated as PZW-PMN-PZT) ceramic systems were fabricated using $Bi_2O_3$, CuO and $Li_2CO_3$ as sintering aids and then their piezoelectric and dielectric properties were investigated according to the amount of $Li_2CO_3$ and post-annealing process. Post-annealing process enhanced all physical properties except for mechanical quality factor (Qm). 0.2 wt% $Li_2CO_3$ added and post-annealed specimen showed the excellent values suitable for low loss piezoelectric actuator application as follow: the density = 7.86 $g/cm^3$ electromechanical coupling factor (kp) = 0.575, piezoelectric constant $d_{33}$ = 370 pC/N, dielectric constant ($\varepsilon_r$) = 1546, and mechanical quality factor (Qm) = 1161, respectively.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.171-174
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• 2000

In this study, the laser patterning of sputter-deposited amorphous CoNbZr films has been tried usig Nd: YAG laser. However, the metal film was not removed because of its high reflectance of the alser on the metal surface. To solve this problem, authors tried to screen-print a block polymer on the metal film and then irradiate the laser on the polymer. This is a new method which was suggested by this study. Using this new method, the metal films were effectively removed with the laser power of 114W even though the metal films was not removed with the laser power of 332W using the conventional method. This result leads to the conclusion that the block polymer acts as a laser energy absorbing and transferring layer.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.111-111
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.218-218
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• 2003

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.1
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• pp.35-39
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• 2006

In this study, in order to develop the multilayer piezoelectric actuator and ultrasonic resonator, PMN-PNN-PZT ceramics were fabricated by sintering with $Li_2CO_3-Na_2CO_3$ as sintering aids at $950^{\circ}C$ and their piezoelectric and dielectric characteristics were investigated as a function of PNN substitution. With increasing PNN substitution, dielectric constant(${\epsilon}_r$), electromechanical coupling factor(kp), and piezoelectric d constant($d_{33}$) were increased to $12 mol\%$ PNN substitution and then showed a tendency to decrease rapidly With increasing PNN substitution, crystal structure changed from tetragonal to rhombohedral at $12 mol\%$ PNN substitution and then secondary phase was appeared and its intensity was increased. At the $12 mol\%$ PNN substituted PMN-PZT composition ceramic sintered at $950^{\circ}C$, density, kp, $d_{33}$ and Qm showed the optimum value of $7.79 g/cm^3$, 0.599, 419 pC/N, and 894, respectively for multilayer piezoelectric actuator application.