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Ferroelectric type materials for actuator applications.

機譯:用于執(zhí)行器的鐵電材料。

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摘要

The works reported in this thesis address three basic problem areas which are associated with different practical uses of ferroelectric type materials for electromechanical actuator applications.; In a low strain precision system such as the Lead Magnesium Niobate: Lead Titanate (PMN:PT) family of electrostrictors, precise reproducibility of the electrostrictive strain and the absence of dielectric hysteresis are essential attractions for the use of these materials. Ageing, which is the slow stabilization of an existing ferroic internal structure, is a phenomenon which effects all normal ferroelectric ceramics, and destroys the reproducibility of electrically induced strain in these systems. In this study, it has been shown that by careful fabrication using high purity oxides, 0.9PMN0.1PT ceramic can be made which shows no ageing. Furthermore, by deliberate doping with Manganese oxide (MnO), ageing can be reintroduced. Through a sequence of studies on isothermal ageing and on ageing under bias fields, the nature of the effective internal bias field associated with ordering the defects induced by doping has been explored and the nature of the ageing process delineated.; For very high strain actuators, it is necessary to make use of the spontaneous strains induced by ferroic phase changes, or by domain switching in a spontaneous polarized state. For these systems, the strain versus field relations are hysteretic but in certain cases the strain is a unique function of polarization, so that charge control of dimensions is now possible. Systems explored in this work included paraelectric: ferroelectric switching above the Curie temperature in single crystal BaTiO{dollar}sb3{dollar} (0.36% strain), 90{dollar}spcirc{dollar} domain switching in single crystal BaTiO{dollar}sb3{dollar} (0.65% strain), antiferroelectric: ferroelectric switching in modified Lead Zirconate Titanate Stannate ceramics (0.85% strain) and ferroelectric switching of morphotropic phase boundary compositions in the PLZT ceramic family (0.54% maximum longitudinal strain). Charge control, coercivity and stability of the remanent strain have been explored and the fatigue effects associated with repeated switching examined.; The kinetics of field induced polarization and strain have been investigated for Pb(Ti,Zr)O{dollar}sb3{dollar} family of ferroelectrics, and for the phase switching in the modified Lead Zirconate Titanate Stannate antiferroelectric ceramics. For both families, switching can be accomplished in microsecond switching times under high fields and kinetics of switching does not limit potential applications.
機譯:本論文報道的工作解決了三個基本問題領(lǐng)域,這些領(lǐng)域與鐵電型材料在機電執(zhí)行器應(yīng)用中的不同實際應(yīng)用有關(guān)。在低應(yīng)變精度系統(tǒng)中,例如鈮酸鉛鎂:鈦酸鉛(PMN:PT)系列電致伸縮管,電致伸縮應(yīng)變的精確再現(xiàn)性和不存在介電滯后是使用這些材料的基本吸引力。老化是現(xiàn)有鐵氧體內(nèi)部結(jié)構(gòu)的緩慢穩(wěn)定,是一種現(xiàn)象,會影響所有普通的鐵電陶瓷,并破壞這些系統(tǒng)中電感應(yīng)應(yīng)變的再現(xiàn)性。在這項研究中,已經(jīng)表明,通過使用高純度氧化物精心制造,可以制成0.9PMN0.1PT陶瓷,且沒有老化。此外,通過故意摻雜氧化錳(MnO),可以重新引入老化。通過對等溫老化和偏置場下老化的一系列研究,探索了有效內(nèi)部偏置場的性質(zhì),該內(nèi)部偏置場與摻雜引起的缺陷的排序有關(guān),并描述了老化過程的性質(zhì)。對于非常高的應(yīng)變致動器,必須利用由鐵性相變或通過在自發(fā)極化狀態(tài)下進行疇切換而引起的自發(fā)應(yīng)變。對于這些系統(tǒng),應(yīng)變與場的關(guān)系是滯后的,但在某些情況下,應(yīng)變是極化的唯一函數(shù),因此現(xiàn)在可以控制尺寸。在這項工作中探索的系統(tǒng)包括順電:單晶BaTiO {sdol} sb3 {dollar}(應(yīng)變?yōu)?.36%)中居里溫度以上的鐵電轉(zhuǎn)換,BaTiO {sdol3sb3 {美元}(應(yīng)變?yōu)?.65%),反鐵電:改性的鋯酸鈦酸鉛錫酸鹽陶瓷中的鐵電轉(zhuǎn)換(應(yīng)變?yōu)?.85%)和PLZT陶瓷系列中相變相邊界成分的鐵電轉(zhuǎn)換(最大縱向應(yīng)變?yōu)?.54%)。已經(jīng)研究了剩余應(yīng)變的電荷控制,矯頑力和穩(wěn)定性,并研究了與反復(fù)切換相關(guān)的疲勞效應(yīng)。已經(jīng)研究了鐵電體的Pb(Ti,Zr)O {sb3 {dollar}族的場致極化和應(yīng)變的動力學(xué),以及改性鋯鈦酸鉛鈦酸鹽Stannate反鐵電陶瓷的相變。對于這兩個系列,切換都可以在高電場下的微秒切換時間內(nèi)完成,并且切換動力學(xué)并不限制潛在的應(yīng)用。

著錄項

  • 作者

    Pan, Wuyi.;

  • 作者單位

    The Pennsylvania State University.;

  • 授予單位 The Pennsylvania State University.;
  • 學(xué)科 Engineering Materials Science.
  • 學(xué)位 Ph.D.
  • 年度 1988
  • 頁碼 257 p.
  • 總頁數(shù) 257
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 工程材料學(xué);
  • 關(guān)鍵詞

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