本文選題：KNN無鉛壓電陶瓷 + 相界構(gòu)建�。� 參考：《西南民族大學》2017年碩士論文

【摘要】：堿金屬鈮酸鹽(KNN)基無鉛壓電陶瓷因其良好的壓電性能和較高的居里溫度,是最有潛力取代鉛基壓電陶瓷的無鉛壓電陶瓷體系之一。為提高KNN陶瓷的電學性能,研究較為廣泛的是降低正交-四方相變溫度(TO-T),在室溫附近構(gòu)建正交-四方相界;或是提高三方-正交相變溫度(TR-O),在室溫區(qū)構(gòu)建三方-正交相界。然而,這兩種手段得到的KNN陶瓷體系的壓電常數(shù)與鉛基壓電陶瓷相比仍存在很大的差距。近年來,研究者提出在KNN陶瓷中構(gòu)建類似于Pb(Zr,Ti)O_3體系的三方-四方準同型相界(R-T相界)的新思路,將TO-T和TR-O同時調(diào)控至室溫附近,成功的得到了一些高性能的KNN陶瓷體系。本論文以“新型相界構(gòu)建”新思路為出發(fā)點,系統(tǒng)研究了(Bi,Sm)_(0.5)Na0.5ZrO_3和(Bi,Me)_(0.5)(Na,K)_(0.5)ZrO_3(簡寫為BSNZ和BMNKZ,其中Me3+=La3+、Nd3+、Sm3+)添加物對(K,Na)NbO_3(KNN)、(K,Na)(Nb,Sb)O_3(KNNS)和(K,Na)(Nb,Ta,Sb)O_3(KNNTS)的微觀形貌、晶體結(jié)構(gòu)、相界演變和宏觀性能的影響。結(jié)果顯示,添加BSNZ和BMNKZ能夠在室溫區(qū)構(gòu)建出R-T/R-O-T相界,從而大大提高了體系的電學性能。本文研究結(jié)果如下:1.采用傳統(tǒng)固相反應法制備了(1-x)K_(0.48)Na_(0.52)NbO_3-x(Bi_(0.46)Nd_(0.04))(Na_(0.82)K_(0.18))_(0.5)ZrO_3(簡寫為KNN-xBNNKZ)、(1-x)K_(0.48)Na_(0.52)NbO_3-x(Bi_(0.46)La_(0.04))(Na_(0.82)K_(0.18))_(0.5)ZrO_3(簡寫為KNN-xBLNKZ)、和(1-x)K_(0.48)Na_(0.52)NbO_3-x(Bi_(0.45)Sm_(0.05))(Na_(0.82)K_(0.18))_(0.5)ZrO_3(簡寫為KNN-xBSNKZ)三個陶瓷體系。研究發(fā)現(xiàn),隨著BMNKZ含量的增加,TO-T和TR-O同時被調(diào)控至室溫附近。當室溫區(qū)實現(xiàn)R-T或R-O-T共存態(tài)時體系壓電性能大幅增強。三個壓電陶瓷體系的最優(yōu)性能如下:KNN-xBNNKZ(x=0.05),d33=308pC/N,kp = 43%,εr=1205,tanδ=3.8%,Pr=23.45 μC/cm2,TC=331 °C;KNN-xBLNKZ(x=0.05),d33=368 pC/N,kp = 44.7%,εr =1358,tanδ=3.5%,Pr=22.8 μC/cm2,Ec=12kV/cm,TC=323°C;KNN-xBSNKZ(x=0.05),d33=342 pC/N,kp = 46%,εr =1476,tanδ=4.3%,Pr=23.7 μC/cm2,Ec=12 kV/cm,TC=328°C。2.采用傳統(tǒng)固相反應法制備了(1-x)K_(0.48)Na_(0.52)Nb0.96Sb0.04O_3-x(Bi_(0.45)Sm_(0.05))(Na_(0.82)K_(0.18))_(0.5)ZrO_3(簡寫為KNNS-x BSNKZ)陶瓷體系。研究發(fā)現(xiàn),隨著BSNKZ含量的增加,體系的TO-T下降較快,而TR-O上升相對緩慢,二者相互靠近最終在室溫區(qū)實現(xiàn)R-T的共存,此時陶瓷的壓電性能最優(yōu):KNNS-xBSNKZ(x=0.045),d33=480 pC/N,kp=48%,εr=2180,tanδ=3.6%,Pr=19.5μC/cm2,Ec=8.1 kV/cm,TC=258°C。3.采用傳統(tǒng)的固相反應法制備了0.96K0.4Na0.6Nb0.97-xTa0.03SbxO_3-0.04(Bi_(0.45)Sm_(0.05))Na0.5ZrO_3(簡寫為KNNTSx-BSNZ)陶瓷體系。研究發(fā)現(xiàn),隨著Sb含量的增加,TO-T和TR-O很快被調(diào)控至室溫附近。當Sb的含量從0.02變到0.07時,陶瓷在室溫附近均為R-T共存,當x=0.045時陶瓷體系性能最優(yōu):KNNTSx-BSNZ(x=0.045),d33=510 pC/N,kp=44%,εr=2136,tanδ=4.1%,Pr=20.4μC/cm2,Ec=7.85 kV/cm,TC=238°C。
[Abstract]:Alkaline niobate (KNN) based lead-free piezoelectric ceramics is one of the most promising lead-free piezoelectric ceramics because of its good piezoelectric properties and high Curie temperature. In order to improve the electrical properties of KNN ceramics, it is widely studied to reduce the temperature of orthorhombic phase transition (TO-T), to construct the quadrature tetragonal phase boundary near room temperature, or to increase the temperature of the orthorhombic phase transition temperature (TR-O) to construct the rhombohedral interphase boundary at room temperature. However, the piezoelectric constants of KNN ceramics obtained by these two methods are still far from those of lead-based piezoelectric ceramics. In recent years, researchers have proposed a new idea of constructing a three-tetragonal quasi-homogeneous phase boundary (R-T phase boundary) similar to Pb (Zr-Ti) O _ 3 system in KNN ceramics. TO-T and TR-O are simultaneously controlled to near room temperature, and some high performance KNN ceramic systems have been successfully obtained. 鏈鏂囦互鈥滄柊鍨嬬浉鐣屾瀯寤衡，

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