本文選題：無鉛鐵電壓電陶瓷 + 固溶體　； 參考：《山東大學(xué)》2017年碩士論文

【摘要】：早在1942年,就有學(xué)者發(fā)現(xiàn)鈦酸鋇(BaTiO_3,BT)可以作為鐵電壓電材料。但純的鈦酸鋇陶瓷的壓電系數(shù)只有190 pC/N左右,這與鋯鈦酸鉛陶瓷可以達到500-600 PC/N的壓電系數(shù)相去甚遠。鋯鈦酸鉛陶瓷的優(yōu)良壓電性能是由于調(diào)整鋯/鈦元素比從而得到了準同型相界。鐵電材料的機電性能與其相結(jié)構(gòu)有著密切的關(guān)系。近年來,有許多工作致力于在室溫下構(gòu)造鈦酸鋇基陶瓷與鈮酸鉀鈉基陶瓷的菱方相-正交相(R-O),正交相-四方相(O-T)以及四方相-菱方相(T-R)相界并成功的在溫度-組分相圖中得到了分離的多晶相轉(zhuǎn)變區(qū)域(PPT)或者準同型相界(MPB)。比如說,可以通過摻入較大的B位離子,來得到O-T以及R-O的多晶轉(zhuǎn)變區(qū)域。但這兩個區(qū)域往往在相隔很遠的組分區(qū)域內(nèi)�；谝陨系囊恍┙�(jīng)驗,本論文嘗試在鈦酸鋇陶瓷中尋找一個合適的組分使鈦酸鋇基的固溶體存在兩個甚至多個鐵電相的過渡共存,從而得到優(yōu)良的機電性能。在元素周期表中,鍶元素(Sr)位于鋇元素(Ba)上方,而鋯元素(Zr)則正好處于鈦元素(Ti)的下方。也就是說,每一種元素都能夠與鈦酸鋇形成連續(xù)固溶體。在本工作中,首先以固相反應(yīng)法合成了鋯鈦酸鍶鋇陶瓷(Ba_(0.95)Sr_(0.05)Zr_xTi_(1-x)O_3,BSZT,x=0.05,0.10,0.15,0.20).研究結(jié)果表明,當(dāng)鋯含量為 5%時,在 1400℃下燒結(jié)的陶瓷樣品具有最優(yōu)異的機電性能。在此條件下,鋯鈦酸鍶鋇陶瓷的剩余極化強度為12.1 μC/cm2,介電常數(shù)峰值ε_r~(peak) ≈12600,室溫下的介電常數(shù)為ε_r~(RT)≈ 3500,其壓電系數(shù)為355pC/N。居里溫度大約在100℃左右。為了進一步研究鋯鈦酸鍶鋇陶瓷的相結(jié)構(gòu)與其機電性能的關(guān)系,本論文又以固相反應(yīng)法合成了鋯鈦酸鍶鋇陶瓷(Ba_(0.95)Sr_(0.08)Zr_xTi_(1-x)O_3,BSZT,x=0.0 1-0.10)。通過控制摻雜元素和組成比以在室溫附近產(chǎn)生相鄰的相界,從而達到相對于組成成分穩(wěn)定的壓電性能。基于多晶相轉(zhuǎn)變(PPT)溫度組成(TppT-x)關(guān)系的優(yōu)化設(shè)計,本論文在BSZT陶瓷中成功合并了室溫附近的正交相-四方相(O-T)和菱方相-正交相(R-O)的PPT區(qū)域。研究表明,室溫附近的兩個相鄰PPT區(qū)域在性能增強方面表現(xiàn)出不同的特征。然而,由于相界的接近,Ba0.95Sr0.05ZrxTi(1-x)O3陶瓷在相當(dāng)寬的組成范圍(0.02≤X≤0.07)中,在室溫附近表現(xiàn)出優(yōu)異的壓電性能,包括大的壓電系數(shù)(312pC/N≤d≤d33≤365pC/N)和高的機電耦合系數(shù)k_p(0.42≤k_p≤0.49)。該方法可以應(yīng)用于具有多種摻雜元素的其它鐵電陶瓷,其協(xié)同效果,可以使得化合物的兩個相界在應(yīng)用溫度附近彼此靠近,從而可以實現(xiàn)在相當(dāng)寬的組成范圍內(nèi)保持較強的機電性能。
[Abstract]:As early as 1942, some scholars found that barium titanate can be used as ferroelectric material. However, the piezoelectric coefficient of pure barium titanate ceramics is only about 190pC / N, which is far from the piezoelectric coefficient of 500-600PC / N of lead zirconate titanate ceramics. The excellent piezoelectric properties of lead zirconate titanate ceramics are due to the adjustment of the zirconium / titanium ratio to obtain the quasi-homogenous phase boundary. The mechanical and electrical properties of ferroelectric materials are closely related to their phase structure. In recent years A lot of work has been done to construct the rhombohedral, orthorhombic, orthotropic, tetragonal and tetragonal / rhombohedral phase boundaries of barium titanate and potassium sodium niobate ceramics at room temperature. The separated polycrystalline phase transition region (PPTT) or the quasi-homogeneous phase boundary (MPB) have been obtained. For example, the polycrystalline transition regions of O-T and R-O can be obtained by doping larger B-site ions. However, these two regions are often located in distant constituent subregions. Based on the above experiences, this paper attempts to find a suitable component in barium titanate ceramics to make the solid solution of barium titanate exist two or more ferroelectric phase transition coexistence, thus obtaining excellent mechanical and electrical properties. In the periodic table, strontium (Sr) is located above the barium (Ba), and the zirconium (ZrR) is just below the Ti (Ti). That is, each element can form a continuous solid solution with barium titanate. In this work, first of all, barium strontium zirconate ceramics have been synthesized by solid state reaction method. The results show that the ceramic samples sintered at 1400 鈩，

本文編號：2026234