• 한국전기전자재료학회논문지
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• 제13권11호
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• pp.921-925
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• 2000

Characteristics of Pb(Mg, Nb)O$_3$-Pb(Zr, Ti)O$_3$system thick films fabricated by a screen printing method were investigated. The buffer layer were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited Pt as a electrode by sputtering on Ag-Pb layer. The printed thick films were burned out at 650$\^{C}$ and sintered at 950$\^{C}$ in O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20㎛ and Ag-Pb layer acted as a diffusion barrier above 3㎛ thickness. The PMN-PZT thick films were screen printed on Pt/Ag-Pb(6m) and sintered by 2nd step (650$\^{C}$/20min and 950$\^{C}$/1h) using paste mixed PMN-PZT and binder in the ratio of 70:30, and the remnant polarization of thick film was 9.1$\mu$C/㎠ in this conditions.

• 한국재료학회지
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• 제14권11호
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• pp.764-768
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• 2004

Perovskite Pb(Mn_{1/3}Sbu_{2/3})O_2-Pb(Zr,Ti)O_3\;(PMS-PZT) was prepared and ZnO doping effects on its piezoelectric properties were investigated. Pyrochlore phase was not identified in the PMS-PZT ceramics with $0\sim5\;mol\%$ ZnO sintered at $1100^{\circ}C$ for 2 hrs, and maximum sintered density of $7.92 g/cm^3$ was obtained. Piezoelectric charge constant and voltage constant increased to $359{\times}10^{-12}\;C/N\;and\;22.5{\times}10^{-13}\;Vm/N$, respectively, with increasing ZnO content. Mechanical quality factor reduced considerably with increasing ZnO content. When the ZnO content was 3 $mol\%$, electromechanical coupling factor and relative dielectric constant showed maximum values of $56\%$ and 1727, respectively. This should be evaluated by complicated variations of sintered density, tetragonality of lattice, grain size, and A-site vacancy generated by ZnO addition and $Zn^{2+}$ substitution.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2582-2590
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• 2021

The high-energy milling is one of the most extended techniques to produce Oxide dispersion strengthened (ODS) powder steels for nuclear applications. The consequences of the high energy mill process on the final powders can be measured by means of deformation level, size, morphology and alloying degree. In this work, an ODS ferritic steel, Fe-14Cr-5Al-3W-0.4Ti-0.25Y₂O₃-0.6Zr, was fabricated using two different mechanical alloying (MA) conditions (M_std and M_act) and subsequently consolidated by Spark Plasma Sintering (SPS). Milling conditions were set to evidence the effectivity of milling by changing the revolutions per minute (rpm) and dwell milling time. Differences on the particle size distribution as well as on the stored plastic deformation were observed, determining the consolidation ability of the material and the achieved microstructure. Since recrystallization depends on the plastic deformation degree, the composition of each particle and the promoted oxide dispersion, a dual grain size distribution was attained after SPS consolidation. M_act showed the highest areas of ultrafine regions when the material is consolidated at 1100 ℃. Microhardness and small punch tests were used to evaluate the material under room temperature and up to 500 ℃. The produced materials have attained remarkable mechanical properties under high temperature conditions.

• 한국전기전자재료학회논문지
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• 제29권6호
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• pp.332-336
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• 2016

In this study, in order to develop the composition ceramics for ultrasonic sensor with high $d_{33}*g_{33}$, $Pb_{1-3x/2}Bix(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.09}(Zr_{0.5}Ti_{0.5})_{0.88}O_3$(PMW-PNN-PZT) system ceramics were prepared using CuO as sintering aids. And then, their microstructure, piezoelectric and dielectric characteristics were systemetically investigated with bismuth substitution. The PMW-PNN-PZT ceramic specimens could be sintered at sintering temperature of $940^{\circ}C$ by adding sintering aids. At x=0.015 specimen, the density, electromechanical coupling factor($k_p$), dielectric constant, piezoelectric constant($d_{33}$) and piezoelectric figure of merit($d_{33}*g_{33}$) indicated the optimal properties of $7.90g/cm^3$, 0.67, 2,511, 628 pC/N, and $17.7pm^2/N$, respectively, for duplex ultrasonic sensor application.

• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.193-196
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• 2011

Lead zirconate titanate (PZT)/ bismuth ferrite (BFO) multilayer thin films have been fabricated by the spin-coating method on Pt(200 nm)/Ti(10 nm)/$SiO_2$(100 nm)/p-Si(100) substrates using $BiFeO_3$ and $Pb(Zr_{0.52}Ti_{0.48})O_3$ metal alkoxide solutions. The PZT/BFO multilayer thin films show a uniform and void-free grain structure, and the grain size is smaller than that of PZT single films. The reason for this is assumed to be that the lower BFO layers play an important role as a nucleation site or seed layer for the formation of homogeneous and uniform upper PZT layers. The dielectric constant and dielectric losses decreased with increasing number of coatings, and the six-layer PZT/BFO thin film has good properties of 162 (dielectric constant) and 0.017 (dielectric losses) at 1 kHz. The remnant polarization and coercive field of three-layer PZT/BFO thin films were 13.86 ${\mu}C/cm^2$ and 37 kV/cm respectively.

• 한국인터넷방송통신학회논문지
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• 제12권1호
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• pp.245-248
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• 2012

본 논문에서는 실리콘 기반의 기술과 차별화하여 저온동시소성세라믹 (LTCC) 기판을 이용하여 대표적 압전물질인 PZT 박막의 최적의 증착조건을 연구하였다. LTCC 기술은 실리콘 기반의 기술에 비하여 낮은 생산 단가, 높은 수율, 3차원 구조물의 용이한 제작성 등으로 인하여 센서 및 액추에이터와 같은 10 um ~ 수백 um 정도의 중규모 디바이스를 제작하는데 있어서 중요한 역할을 담당하고 있다. LTCC 기판은 NEG사의 MLS 22C 상용 파우더를 이용하여 100 um 두께의 그린쉬트를 적층하고 동시소결하여 400 um 두께로 제작하였다. 제작한 기판위에 Pt/Ti 하부전극을 증착하고 RF 마그네트론 스퍼터링 방법을 이용하여 PZT 박막의 증착조건을 연구하였다. 증착조건으로는 RF 전력과 아르곤과 산소 가스비를 가변하여 실시하였으며, XRD와 EDS를 사용하여 박막의 결정성 및 성분을 분석하였다. 실험을 통하여 얻어진 최적의 증착조건은 RF 전력 125W, 아르곤과 산소비 15:5에서 가장 우수한 특성을 나타내는 것을 확인하였다.

• 마이크로전자및패키징학회지
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• 제18권3호
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• pp.9-17
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• 2011

Nano-composite solders have been studied to improve the properties of Pb-free solder joints. The nanoparticles in the composite solders were carbon nanotubes(CNTs), metals (Ag, Ni, Cr, etc.), ceramics (SiC, $ZrO_2$, $TiB_2$, etc.). To fabricate the nano-composite solders, mechanical mixing methods and in-situ fabrication method has been used for well-dispersed nano phase. The characteristic properties of the nano-composite solders were high creep resistance, low undercooling, low IMC growth rate and fine microstructures. More researches on the nano-composite solders are required to improve the processibility and the reliability of the nano-composite solder joints.

• 한국세라믹학회지
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• 제27권2호
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• pp.244-248
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• 1990

The effect of Nd3+ on the electrical and optical properties in PZT ceramics were investigated. The powders were prepared by the coprecipitation method using the salt solutions and Nd3+ was partially substituted for Pb2+ of Pb(Zr0.54 Ti0.46)O3. The coprecipitate were obtained under pH 11.8-12 and the single phase of PLZT powders were synthesized at about 500$^{\circ}C$. In the case of specimens with 4at.% of Nd which were sintered at 1250$^{\circ}C$ for 55 hours under 1atm, showed 50% of transmittance for 600nm(wave length).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1456-1457
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• 2008

본 논문에서는 박막 PZT(Pb(Zr,Ti)O3)를 이용한 d33모드의 자가 발전 소자를 설계 및 제작 하였다. 자가 발전 소자는 진동 에너지를 압전 현상을 통해 전기 에너지로 변환하는 소자로서, 제안한 구조는 단일 외팔보가 아닌 20개 이상의 외팔보를 원형으로 집적한 구조를 갖기 때문에, 기존의 단일 외팔보 위주의 자가발전 소자보다 출력 전력이 우수하다. 자가 발전 소자의 성능 최적화를 위해 유한요소기법(FEM)을 통해 기계적 특성을 분석하였으며, 마이크로 머시닝 기법을 이용하여 초박형의 자가 발전 소자를 제작할 수 있었다. 제작된 자가발전 소자는 $1.2mm\times1.2mm\times0.5mm$ (높이)의 크기를 갖는다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.179-182
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• 1999

A new band pass filter (BPF) prepared by dielectric monoblock and its design techniques are presented. The modeling of the three-pole dielectric monoblock BPF has been carried out by CAD. The equivalent circuit of the BPF was established by transmission lines and lumped capacitors. The transmission line characteristic impendances were computed using 2-D FEM. The BPF for PCS has been designed to have a 60 MHz pass-bandwidth with center frequency of 1960 MHz and an attenuation pole at below the passband using a commercial 3-D structure simulator.