• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.260-261
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• 2005

The heterolayered thick/thin structure consisting of $Pb(Zr_{0.52}Ti_{0.48})O_3$ and $BaTiO_3(BT)$ were fabricated by a sol-gel process. PZT powders, prepared by the sol-gel method, were mixed with an organic vehicle and the PZT thick films were fabricated by the screen printing techniques on alumina substrate with Pt electrodes. The microstructural and dielectric characteristics of the stacked heterolayered PZT/BT/PZT films were investigated by varying the number of coating $BaTiO_3$ layers. The existence of a $BaTiO_3$ layer between the PZT thick films of the tri-layer $Pb(Zr_xTi_{1-x})O_3/BaTiO_3/Pb(Zr_xTi_{1-x})O_3$thick/thin/thick film can greatly improve the leakage current properties of the PZT thick films. The average thickness of a PZT(5248)/$BaTiO_3$ heterolayered thick/thin film was 25$\mu$m. The relative dielectric constant and dielectric loss of the PZT(5248)/$BaTiO_3$-3 heterolayered thin film coated three times were 1087 and 1.00% at 1[MHz].

• 한국세라믹학회지
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• 제40권1호
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• pp.37-45
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• 2003

$BaTiO_3$의 Ba 자리에 Ca, Ti 자리에 Zr을 첨가한 $(B a_{1-x}Ca_x)(Ti_{0.96-y}Zr_{y}Sn_{0.04})O_3$ $(0.15 {\leq} x{\leq}0.20,\; 0.09{\leq}y{\leq}$0.14) 조성에 2차상 형성을 유도하여 복합체를 만든 후 유전 및 소결 특성을 조사하였다. Ca량이 15mol% 이상 첨가됨에 따라 $CaTiO_3$를 주성분으로 하는 2차상이 석출하여 복합체가 형성되었으며, Ca량의 증가에 따라 2차상 분율이 증가하였다. Ca량의 증가는 큐리 온도를 mol%당 $1.7^{\circ}C$ 감소시키며, 저유전율 2차상의 영향으로 Ca량 증가에 따라 최대 유전율은 mol%당 200 감소하였다. Zr 첨가는 큐리온도를 mol%당 $10^{\circ}C$ 감소시키며, 확산형 상전이 현상을 증가시켜 최대 유전율을 217 감소시켰다. 2차상의 증가에 의하여 비정상 입성장이 억제되어 소결밀도, 내전압 특성이 향상되었으며, Zr 첨가에 의하여 커패시턴스의 온도 안정성을 제어하여 EIA 규격을 만족하는 고압, 고유전율 Y5U 콘덴서 조성을 개발하였다.

• 한국전기전자재료학회논문지
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• 제37권3호
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• pp.274-279
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• 2024

Eu³⁺-doped BaZrO₃ (BaZrO₃:Eu³⁺) phosphor powders were prepared using a solid-state reaction by changing the molar concentration of Eu³⁺ within the range of 0.5 to 30 mol%. Irrespective of the molar concentration of Eu³⁺ ions, the crystal structures of all the phosphors were cubic. The excitation spectra of BaZrO₃:Eu³⁺ phosphors consisted of an intense broad band centered at 277 nm in the range of 230~320 nm. The emission spectra were composed of a dominant orange band at 595 nm arising from the ⁵D₀→⁷F₁ magnetic dipole transition of Eu³⁺ and two weak emission bands centered at 574 and 615 nm, respectively. As the concentration of Eu³⁺ increased from 0.5 to 10 mol%, the intensities of all the emission bands gradually increased, approached maxima at 10 mol% of Eu³⁺ ions, and then showed a decreasing tendency with further increase in the Eu³⁺ ions due to the concentration quenching. The critical distance between neighboring Eu³⁺ ions for concentration quenching was calculated to be 11.21 Å, indicating that dipole-dipole interaction was the main mechanism of concentration quenching of BaZrO₃:Eu³⁺ phosphors. The results suggest that the orange emission intensity can be modulated by doping the appropriate concentration of Eu³⁺ ions.

• 한국전기전자재료학회논문지
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• 제30권4호
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• pp.223-228
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• 2017

In this study, in order to develop composition ceramics for refrigeration device application at a temperature of less than $90^{\circ}C$, a $Ba(Ti_{1-x}Zr_x)O_3$ composition was fabricated using a conventional solid-state method. Electrocaloric properties of these ceramics were investigated using the characteristics of P-E hysteresis loops in a wide temperature range from room temperature to $150^{\circ}C$. The Curie temperature of $Ba(Ti_{1-x}Zr_x)O_3$ ceramics decreased with the increase of x. The maximum value of ${\Delta}T=0.07^{\circ}C$ in an ambient temperature of $85^{\circ}C$ under 30 kV/cm appeared when x = 0.125. It was concluded that the composition (x = 0.125) ceramics can be used for refrigeration device applications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.785-786
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• 2012

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.1-5
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• 2006

The effect of A/B moi ratios and sintering temperatures on dielectric properties and microstructure of $(Ba_{0.93}Ca_{0.07})_m(Ti_{0.82}Zr_{0.18})O_3$ ceramics were investigated. The dielectric constant decreased with increasing the A/B mol ratio. However, the dielectric loss is improved. As the dielectric properties of A/B mol ratio with m = 1.009 at sintered temperature $1260^{\circ}C$, we obtained dielectric constant 12,800, dielectric loss $3.5\%$ and Y5V temperature characteristics. Highly reliable Ni-MLCCs, 1.6mm$(length){\time}0.8mm(width){\time}0.8mm$(height) with capacitance of 1.23 ${\mu}F$ and 야ssipation loss of $5.2\%$ were obtained employing dielectric material composed of $(Ba_{0.93}Ca_{0.07})_{1.009}(Ti_{0.82}Zr_{0.18})O_3$ - $MnO_2\;0.2wt\%-Y_2O_3\;0.18wt\%,\;-\;SO_2\;0.15wt\%-(Ba_{0.4}Ca_{0.6})SiO_3\;1wt\%$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1436-1437
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• 2011

(1-x)(Na,K)$NbO_3$-xBa(Zr,Ti)$O_3$ lead free piezoelectric ceramics were synthesized to enhance the piezoelectric properties of (Na,K)$NbO_3$. The synthesis and sintering method were the conventional solid state reaction method and general sintering method in air atmosphere. We report the improved piezoelectric properties in the perovskite structure composed of the NKN and BZT ceramics. We investigated the effects of NKN, BZT on the structural and electrical properties of the NKN-BZT ceramics. The NKN-BZT ceramics show good performance with piezoelectric constant $d_{33}$=155pC/N. The results reveal that (1-x)(Na,K)$NbO_3$-xBa(Zr,Ti)$O_3$ ceramics are promising candidate materials for lead-free piezoelectric application.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 추계학술발표회
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• pp.142-142
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• 1997

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.92.2-92
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• 2002

• 한국세라믹학회지
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• 제24권6호
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• pp.586-592
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• 1987

The role of the strain energy and phase stability in the diffuse phase transition have been investigated in the highly disordered solid solution, (Pb1-xBax)(Zr0.4Ti0.6)O3 (0.2 x 0.4). X-ray diffraction analysis indicates that tetragonality (c/a) decreases with the increasing Ba content. Also as the Ba content increases, phase transition becomes more diffuse and at the same time dielectric relaxation as a function of measured frequencies in the 1KHz-10MHz range occurs very pronouncedly. In the Ba content range, 0.2 x 0.35, hysteresis loops are routinely observed and the loop is observed to narrow shape as the Ba content increases but becomes very slim at 40mol% Ba content. Moreover thermal analysis shows that there is no abrupt change in the thermal expansion coefficient below the apparent transition temperature at which dielectric constant becomes maximum. From the above results, it has been concluded that creation of the strain energy due to the distorthion that occurred during the phase transition suppresses diffuse phase transition.