Microstructure Control of Lead Niobate for Piezoelectric Transducers

压电换能器用铌酸铅的微观结构控制

• 批准号: 11650700
• 负责人: KIMURA Toshio
• 金额: $ 0.45万
• 依托单位: Keio University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650700/
• 关键词: Lead Niobate; Sintering; Microstructure; Dopant; Lanthanum Oxide; Piezoelectric Properties; 誘電特性

The effects of La_2O_3 doping on the microstructure and piezoelectric properties of PbNb_2O_6 were examined. Extensive grain growth induced by the phase transformation form the low- to high-temperature forms was suppressed by La_2O_3 doping. Furthermore, La_2O_3 reduced the rate of normal grain growth and the phase transformation temperature. Thus, dense, fine-grained ceramics were obtained. La_2O_3 increased the frequency and dielectric constants. The elimination of pores and cracks were responsible for the increase in the frequency constant. La acts as donor ion to PbNb_2O_6 and increases the dielectric constant. Co-doping of La_2O_3 and K_2O resulted in an increase in the rate of normal grain growth. This result suggests that grain boundary segregation of La ions is responsible for the reduction of the rate of normal grain growth. These results indicates that PbNb_2O_6 doped with La_2O_3 has small mechanical quality factor and large frequency constant, and can be used as basic composition for the piezoelectric material with wideband ultrasonic transducers. The compact with the composition of Pb_<0.95>La_<0.10/3>Nb_2O_6 and sintered at 1200℃ had frequency constant of 2175 kHzmm, dielectric constant of 616, and mechanical quality factor of 147.

研究了La_2O_3掺杂对PbNb_2O_6的微观结构和压电性能的影响。La_2O_3掺杂抑制了低温相变到高温相变引起的粗大晶粒长大。此外，La_2O_3还降低了正常晶粒长大速度和相变温度。从而获得了致密、细晶的陶瓷。La_2O_3提高了材料的频率和介电常数。气孔和裂纹的消除是导致频率常数增加的原因。La作为PbNb_2O_6的施主离子，提高了介电常数。La_2O_3和K_2O的共同掺杂提高了晶体的正常生长速度。这一结果表明，La离子的晶界偏析是导致正常晶粒长大速率降低的原因。结果表明，掺La_2O_3的PbNb_2O_6具有较小的机械品质因数和较大的频率常数，可作为宽带超声换能器的基本组成材料。由Pb0.95&gt；La&lt；0.10/3&gt；Nb2O6组成，1200℃烧结的压坯，其频率常数为2175kHzmm，介电常数为616，机械品质因数为147。

项目成果

Masataka Kato: "Effects of La_2O_3 on the Microstructure and Piezoelectric Properties of PbNb_2O_6"Fewoelectrics.

加藤正孝：“La_2O_3对PbNb_2O_6微观结构和压电性能的影响”。

Masataka Kato: "Effects of La_2O_3 on the Microstructure and Piezoelectric Properties of PbNb_2O_6"Key Engineering Materials. (2001)

加藤正孝：“La_2O_3对PbNb_2O_6微观结构和压电性能的影响”关键工程材料。

Masataka Kato: "Effects of La_2O_3 on the Microstructure and Piezoelectric Properties of PbNb_2O_6"Ferroelectrics.

加藤正孝：“La_2O_3对PbNb_2O_6的微观结构和压电性能的影响”铁电体。

M.Kato: "Effects of La_2O_3 on the Microstructure and Piezoelectric Properties of PbNb_2O_6"Key Engineering Materials. (2001)

M.Kato：“La_2O_3对PbNb_2O_6微观结构和压电性能的影响”关键工程材料。

M.Kato: "Effects of La_2O_3 on the Microstructure and Piezoelectric Properties of PbNb_2O_6"Ferroelectrics.

M.Kato：“La_2O_3 对 PbNb_2O_6 的微观结构和压电性能的影响”铁电体。