• Title/Summary/Keyword: $Bi_{0.5}K_{0.5}TiO_3$

Search Result 158, Processing Time 0.038 seconds

Influence of $TiO_2$ on the dielectric properties of $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramics for low-firing (저온소결용 $Bi(Nb_{0.7}Ta_{0.3})O_4$ 세라믹스의 유전특성에 미치는 $TiO_2$ 영향)

  • Kim, Dae-Min;Yoon, Sang-Ok;Kim, Kwan-Soo;Kim, Shin;Kim, Jae-Chan;Kim, Kyung-Joo;Park, Jong-Guk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2007.06a
    • /
    • pp.298-298
    • /
    • 2007
  • Influence of $TiO_2$ on the dielectric properties of the $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic with 7 wt% zinc borosilicate(ZBS) glass was investigated as a function of the $TiO_2$ contents with a view to applying this system to LTCC technology. The $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic addition of 7 wt% ZBS glass ensured successful sintering below $900^{\circ}C$. But, TCF of $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic is large negative values, respectively, it is necessary to adjust to zero TCF for practical applications Therefore, the addition of materials having positive TCF, such as $TiO_2$, might be an effective method for the improvement. In general, increasing addition of $TiO_2$ increased dielectric constant and TCF but it decreased the sinterability and $Q{\tiems}f$ value significantly due to the dielectric property and high sintering temperature of $TiO_2$. $Bi(Nb_{0.7}Ta_{0.3})O_4$ ceramic with 7 wt% ZBS glass and then addition 0.5 wt% $TiO_2$ sintered at $900^{\circ}C$ demonstrated 42 in the dielectric constant(${\varepsilon}_r$), 1,000 GHz in the $Q{\times}f$ value, and $10{\pm}5\;ppm/^{\circ}C$ in the temperature coefficient of resonant frequency(${\tau}_f$).

  • PDF

Properties of Piezoelectric Generators and K0.5Bi0.5TiO3 Films Prepared by Sol-Gel Method (졸-겔법에 의해 제조한 K0.5Bi0.5TiO3 막과 압전발전기의 특성)

  • Lee, Young-Ho;Park, Sang-Shik
    • Korean Journal of Materials Research
    • /
    • v.31 no.11
    • /
    • pp.649-656
    • /
    • 2021
  • K0.5Bi0.5TiO3 (KBT) thin films were prepared by sol-gel processing for future use in piezoelectric generators. It is believed that the annealing temperature of films plays an important role in the output performance of piezoelectric generators. KBT films prepared on Ni substrates were annealed at 500 ~ 700 ℃. Tetragonal KBT films were formed after annealing process. As the annealing temperature increased, the grain size of KBT films increased. KBT thin films show piezoelectric constant (d33) from 23 to 41 pC/N. The increase of grain size in KBT films brought about output voltage and current in the KBT generators. Also, the increase in the displacement of specimens during bending test resulted in increases in output voltage and current. Although KBT generators showed lower output power than those of generators prepared using NBT films, as reported previously, the KBT films prepared by sol-gel method show applicability as piezoelectric thin films for lead-free nano-generators, along with NBT films.

Piezoelectric Properties and Phase Transition behaviors of (Bi1/2Na1/2)1- xCaxTiO3Ceramics ((Bi1⁄2Na1⁄2)1-xCaxTiO3 세라믹스의 압전 특성 및 상전이 거동)

  • Lee, Yong-Hyun;Cho, Jeong-Ho;Kim, Byung-Ik;Choi, Duck-Kyun
    • Journal of the Korean Ceramic Society
    • /
    • v.45 no.5
    • /
    • pp.263-267
    • /
    • 2008
  • $(Bi_{1/2}Na_{1/2})TiO_3$-based ceramics have been intensively studied as lead-free piezoelectric ceramics. In this study, the piezoelectric properties and phase transition behaviors of BNT based solid solution $(Bi_{0.5}Na_{0.5})_{1-x}Ca_xTiO_3$ ($X=0.01{\sim}0.25$) were investigated. The morphotropic phase boundary(MPB) zone which BNT is transformed from rhombohedral to cubic structure was appeared by adding $CaTiO_3$ with 0.12 mol by the measurement of permittivity and X-ray diffraction. The behavior which ferroelectric BNT with adding $CaTiO_3$ was changed to antiferroelectric and paraelectric state was confirmed by the measurement ofhysterisis loop and depolarization temperature as a function of temperature. As $CaTiO_3$ concentration was increased, the phase transition temperature was decreased. The piezoelectric properties were highest at 0.01 mol of $CaTiO_3$ concentration. The electromechanical coupling factor($K_t$) and mechanical quality factor($Q_m$) were 42% and 254, respectively.

Piezoelectric and Dielectric Properties of 0.97[(K0.5Na0.5)(Nb0.97Sb0.03)O3]-0.03[(Bi0.5K0.5)TiO3] Ceramics Modified with K5.4Cu1.3Ta10O29 (K5.4Cu1.3Ta10O29 첨가에 따른 0.97[(K0.5Na0.5)(Nb0.97Sb0.03)O3]-0.03[(Bi0.5K0.5)TiO3] 세라믹스의 압전 및 유전 특성)

  • Lee, Kab-Soo;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.24 no.9
    • /
    • pp.728-732
    • /
    • 2011
  • In this study, piezoelectric and dielectric properties of Lead-free $0.97[(K_{0.5}Na_{0.5})(Nb_{0.97}Sb_{0.03})O_3]+0.03[(Bi_{0.5}K_{0.5})TiO_3]$ (abbreviated as 0.97NKNS-0.03BKT)ceramics synthesized by conventional solid-state reaction process were investigated as a function of $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition. The results indicated that the $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition significantly improved the sinterability, grain growth and piezoelctric properties of 0.97NKNS-0.03BKT ceramics. The optimum values as planar piezoelectric coupling coefficient ($k_p$= 0.355), piezoelectric constant ($d_{33}$= 207 pC/N) and mechanical quality factor ($Q_m$= 128) were obtained when 0.009KCT was added. The electromechanical coupling factor($k_p$) was slightly decreased according to the increasing temperature.

Effect of $Na_2Ti_6O_{13}$ on Microstructure and PTCR Characteristics of $BaTiO_2-(Bi_{0.5}Na_{0.5})TiO_3$ ceramics ($Na_2Ti_6O_{13}$ 첨가에 따른 $BaTiO_2-(Bi_{0.5}Na_{0.5})TiO_3$ 세라믹스의 미세구조 및 PTCR 특성에 미치는 영향)

  • Cha, Yu-Joung;Kim, Chul-Min;Jeong, Young-Hun;Lee, Young-Jin;Paik, Jong-Hoo;Lee, Woo-Young;Kim, Dae-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2010.06a
    • /
    • pp.15-15
    • /
    • 2010
  • $Na_2Ti_6O_{13}$ (NT)가 도핑된 $BaTiO_3-(Bi_{0.5}Na_{0.5})TiO_3$ BBNT) PTCR 세라믹스를 변형된 세라믹공정을 이용하여 제조하였다. 제조된 BBNT 세라믹의 미세구조와 PTCR 특성에 미치는 NT의 효과를 조사하였다. $1300^{\circ}C$에서 합성된 BBNT 세라믹은 NT의 도핑량이 증가함에 따라 비정상적으로 성장된 입자의 수가 증가하였다. 뿐만 아니라, NT의 도핑량 증가는 상온비저항을 약간 증가시켰지만 큐리온도 (Tc) 부근의 최대비저항/최소비저항으로 정의되는 PTC 점프 특성을 크게 향상시켰다. 특히, 0.01mol%의 NT 도핑 시 상온비저항은 $425\;\Omega{\cdot}cm$, PTC 점프는 ($2.02{\times}^10^5$) 저항온도계수는 69.8% 및 Tc는 $155^{\circ}C$의 우수한 결과를 나타내었다.

  • PDF

The Effect of Ta-substitution on the Bi-O Bonding and the Electrical Properties of $Bi_4$$Ti_3$$O_{12}$ Thin Films ($Bi_4$$Ti_3$$O_{12}$ 박막에서 Bi-O 결합과 전기 물성에 대한 Ta 치환의 영향)

  • 고태경;한규석;윤영섭
    • Journal of the Korean Ceramic Society
    • /
    • v.38 no.6
    • /
    • pp.558-567
    • /
    • 2001
  • 본 연구에서는 알콕사이드를 전구물질로 하는 졸겔공정을 이용하여 Bi 과잉 12 mol%의 조성인 B $i_4$ $Ti_3$ $O_{12}$ 박막과 B $i_4$ $Ti_{3-x}$T $a_{x}$ $O_{12}$(x=0.1, 0.2, 0.3) 박막을 제조하였다. XPS 분석에 따르면 Ta 치환 x=0.2에서 Bi 4f의 photoemission 곡선이 낮은 결합에너지로 이동하였고 피크 강도가 감소하는 현상이 관측되었다. 이는 x=0.1과 0.2 사이에서 Bi-O 결합이 길어져 인장상태 하에 있었음을 나타내었다. B $i_4$ $Ti_3$ $O_{12}$(BIT) 박막의 유전상수와 유전손실은 100 kHz에서 340, 0.05이었고, B $i_4$ $Ti_{3-x}$T $a_{x}$ $O_{12}$ 박막에서 이들 값은 x=0.1에서 가장 높았으며, 각각 480, 0.13이었다. B $i_4$ $Ti_3$ $O_{12}$ 박막의 잔류분극과 항전계는 1.24$\mu$C/$ extrm{cm}^2$, 31.4 kV/cm 이었으나, Ta 치환 x=0.2에서 이들 값은 각각 19.7$\mu$C/$\textrm{cm}^2$, 49.5 kV/cm 에 이르렀다. 또한, B $i_4$ $Ti_3$ $O_{12}$ 박막의 누설전류 밀도는 ~$10^{-6}$ A/$\textrm{cm}^2$ 정도이었으며, Ta 치환은 누설전류를 감소시켜 Ta 치환 x=0.2 이상에서 BIT 박막에 비해 한 차수 정도 낮아졌다. Ta 치환에 따른 B $i_4$ $Ti_3$ $O_{12}$ 전기 물성에서 변화는 Bi-O 결합에서 관측된 인장상태로의 전이와 연관성이 있었으며, 덧붙여 치환에서 생성된 전자에 의한 정공보상이 이에 영향을 끼쳤다. 정공보상이 이에 영향을 끼쳤다.끼쳤다.

  • PDF

Microwave Dielectric Properties of BaO-$(Nd,\;Bi)_2O_3-Tio_2$ Ceramic for Microwave Resonators (고주파 공진기용 BaO-$(Nd,\;Bi)_2O_3-Tio_2$계 세라믹스의 마이크로파 유전특성)

  • Yoon, Jung-Rag;Lee, Heun-Yong
    • Proceedings of the KIEE Conference
    • /
    • 1997.11a
    • /
    • pp.320-323
    • /
    • 1997
  • The microwave dielectric properties of X Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3$-(0.85-X) $TiO_2$ ($X=0.13{\sim}0.17$) and 0.16Ba0-$0.15(Bi_xNd_{1-x})_2O_3-0.69TiO_2$ ($X=0.10{\sim}0.16$) ceramics were investigated. Dielectric constant, quality factor and temperature coefficient of resonant frequency of 0.16Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3-0.69TiO_2$ ceramics sintered at $1320^{\circ}C$ for 2 hours were 89.2, 1920(at 4GHz) and 5.2ppm/$^{\circ}C$, respectively.

  • PDF

Electrical Properties of pressure sensor using a Pb-free $Bi(Na,K)TiO_3-SrTiO_3$ Ceramics (무연 $Bi(Na,K)TiO_3$계 세라믹을 이용한 압력센서의 전기적 특성)

  • Lee, Hyun-Seok;Yoo, Ju-Hyun;Jeong, Yeong-Ho;Hong, Jae-Il;Chung, Kwang-Hyun;Ryu, Sung-Lim
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.11a
    • /
    • pp.387-391
    • /
    • 2004
  • [ $(Bi_{1/2}Na_{1/2})TiO_3$ ](BNT) is considered to be an excellent candidate for the key material of lead-free piezoelectric ceramic due to properties of strong ferroelectricity with a relatively large remanent polarization $Pr=38{\mu}C/cm^2$, and a large coercive field, Ec=73KV/cm. In this study, electrical properties of pressure sensor using a $0.96Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3+0.04SrTiO_3+0.2wt%La_2O_3$ ceramics are investigated. Resonant frequency of pressure sensor was decreased with increasing pressure. However, its anti-resonant frequency was increased with increasing pressure.

  • PDF

Enhancement of PTCR Characteristics of MnO2 Doped Lead Free BaTiO3-(Bi0.5Na0.5)TiO3 Ceramics with High Tc (>165℃) (MnO2가 도핑된 무연 High Tc (>165℃) BaTiO3-(Bi0.5Na0.5)TiO3 세라믹의 PTCR 특성 향상)

  • Kim, Kyoung-Bum;Jang, Young-Ho;Kim, Chang-Il;Jeong, Young-Hun;Lee, Young-Jin;Paik, Jong-Hoo;Lee, Woo-Young;Kim, Dae-Joon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.24 no.9
    • /
    • pp.723-727
    • /
    • 2011
  • 0.935Ba$TiO_3$-0.065($Bi_{0.5}Na_{0.5}$)$TiO_3+xmol%MnO_2$ (BBNTM-x) ceramics with $0{\leq}x{\leq}0.05$ were fabricated with muffled sintering by a modified synthesis process. Their microstructure and enhanced positive temperature coefficient of resistivity (PTCR) characteristics were systematically investigated in order to obtain lead-free high TC PTCR thermistors. All specimens showed a perovskite structure with a tetragonal symmetry and no secondary phase was observed. Grain growth was achieved when the doped MnO2 was increased above 0.02 mol%. This is due to the effect of positive Mn ion doping as an acceptor compensating a Ba vacancy occurred by the higher donor dopant concentration of $Bi^{3+}$ ion. Especially, enhanced PTCR characteristics of the extremely low ${\rho}_{RT}$ of $9\;{\Omega}{\cdot}cm$, PTCR jump of $5.1{\times}10^3$, ${\alpha}$ of 15.5%/$^{\circ}C$ and high $T_C$ of $167^{\circ}C$ were achieved for the BBNTM-0.04 ceramics.

Electrical and structural properties of BNT/BT multilayered thick films (BNT/BT 다층 박막의 구조적, 전기적 특성)

  • Nam, Sung-Pill;Noh, Hyun-Ji;Lee, Sung-Gap;Bea, Seon-Gi;Lee, Young-Hie
    • Proceedings of the KIEE Conference
    • /
    • 2009.07a
    • /
    • pp.1324_1325
    • /
    • 2009
  • The heterolayered $BaTiO_3/(Bi_{0.5}Na_{0.5})TiO_3$ thick films were fabricated by screen printing techniques on alumina substrates electrodes with Pt. We report the improved ferroelectric properties in the heterolayered teteragonal/rhombohedral structure composed of the $BaTiO_3$ and the $(Bi_{0.5}Na_{0.5})TiO_3$ thick films. We investigated the effects of deposition conditions on the structural and electrical properties of the heterolayered BNT/BT thick films. The structural and electrical properties of the heterolayered BNT/BT thick films were studied. All PZT heterolayered thin films show dense and homogeneous structure without the presence of the rosette structure. The dielectric constant, loss and remanent polarization oft heheterolayered BNT/BT thick films were superior to those of single composition $BaTiO_3$ and $(Bi_{1/2}Na_{1/2})TiO_3$, and those values for the heterolayered BNT/BT thick films sintered at $1100^{\circ}C$ were 916, 0.79 and $12.63{\mu}C/cm^2$.

  • PDF