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折扣與優(yōu)惠:團(tuán)購(gòu)最低可5折優(yōu)惠 - 了解詳情 | 論文格式:Word格式(*.doc) | ![]() |
摘要:BaTiO3(BT)是發(fā)現(xiàn)最早的無鉛壓電陶瓷,也是最先獲得應(yīng)用的壓電陶瓷材料。然而,由于BT陶瓷的居里溫度較低(TC約120℃),壓電性能不足(d33約190pC/N),目前BT基陶瓷主要作為介電材料應(yīng)用(如多層陶瓷電容器),作為壓電應(yīng)用已不多見。近年來,人們對(duì)BT基無鉛壓電陶瓷給予了高度關(guān)注。本實(shí)驗(yàn)通過傳統(tǒng)的固相反應(yīng)法,在1450℃-1510℃的溫度、燒結(jié)2小時(shí)制備了無鉛壓電陶瓷xBaTiO3-yCaTiO3-(1-x-y)BaZrO3。研究了xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的相結(jié)構(gòu)和電學(xué)性能,探討了燒結(jié)溫度、組成對(duì)xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷致密度的影響及極化條件對(duì)其電學(xué)性能的影響。不同溫度燒結(jié)的、不同組成的xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的主晶相都是鈣鈦礦結(jié)構(gòu)。隨著CT含量的增加,xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的晶體結(jié)構(gòu)從贗立方相向四方相轉(zhuǎn)變。xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的電阻率達(dá)到了109Ωm數(shù)量級(jí),顯示了較好的絕緣性能。xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷呈現(xiàn)接近正常鐵電體的介電響應(yīng)峰,但是由于三元固溶體的形成,xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的介電響應(yīng)峰存在明顯的寬化現(xiàn)象。xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷呈現(xiàn)飽和對(duì)稱的電滯回線,隨著Ca含量的增加及Zr含量的減少,xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的剩余極化強(qiáng)度Pr與矯頑場(chǎng)EC逐漸增加。隨著Ca含量的增加與Zr含量的減少,xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的居里溫度逐漸升高,但總體偏低(未超過120℃)。隨著極化電場(chǎng)的升高,xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的壓電性能隨之升高。當(dāng)極化電場(chǎng)為2.5kV/mm時(shí),xBaTiO3-yCaTiO3-(1-x-y)BaZrO3陶瓷的壓電性能基本達(dá)到最大值。 關(guān)鍵詞:鈣鈦礦結(jié)構(gòu);BaTiO3;壓電性能;居里溫度
Abstract:BaTiO3 (BT) is the earliest discovered lead-free piezoelectric ceramics and the first applicable piezoelectric ceramic materials. However, due to the low Curie temperature (TC is about 120℃), and the relatively poor piezoelectric properties (d33 is about 190pC/N), BT-based ceramics are mainly used as dielectric materials applications (such as multilayer ceramic capacitors). As comparison, it has been rare to be used as the piezoelectric materials. In recent years, the BT-based lead-free piezoelectric ceramic is given high-level attention. In this study, the lead-free xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 piezoelectric ceramics are prepared by the conventional solid-state reaction method sintered at 1450℃-1510℃ for 2 hours. Crystal structure and electrical properties of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics were studied. The influences of sintering temperature and composition on the phase formation and density, and the impact of polarization conditions on the electrical properties of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics were researched. The synthesized xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics exhibit perovskite structure with slight content of impurity. With the increase of the CT content, the crystal structure of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics changes gradually from pseudo cubic phase to tetragonal phase. The resistivity of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics reaches the magnitude of 109Ωm, indicating the excellent insulated performance of the synthesized ceramics. The xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics exhibit dielectric response character nearly similar to that of the normal ferroelectrics, but the dielectric peaks are obviously broaden due to the formation of the ternary solid solution. The xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics exhibit symmetric and saturated P-E hysteresis loops. With the increase of Ca content and the decrease of Zr content, the values of remnant polarization Pr and coercive field Ec increase gradually. The Curie temperature of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics also increases gradually with the increase of Ca content and the decrease of Zr content, but the Curie temperature is still less than 120℃. With the increase of the polarization electric field, the piezoelectric properties of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics increase greatly. When the polarization electric field is 2.5kV/mm, piezoelectric constant d33 of most compositions of the xBaTiO3-yCaTiO3-(1-x-y)BaZrO3 ceramics exhibit the maximum values. Keywords: perovskite structure; BaTiO3; piezoelectric properties; Curie temperature
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