發(fā)布時(shí)間：2018-03-17 08:12

  本文選題：鈮酸鉀鈉　切入點(diǎn)：熱壓燒結(jié)　出處：《常州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：利用燒結(jié)助劑通過熱壓燒結(jié)工藝成功制備了鈣鈦礦結(jié)構(gòu)的鈮酸鉀鈉(KNN)基透明陶瓷。研究了稀土摻雜后透明陶瓷的光學(xué)性能和熒光特性,以及引入Sr2+、Ba2+后對(duì)介電及壓電性能的影響。具體研究?jī)?nèi)容包括:(1)采用熱壓燒結(jié)工藝,以Li和Bi作為燒結(jié)助劑,制備了鈮酸鉀鈉基上轉(zhuǎn)換透明陶瓷K0.5(1-y)Na0.5(1-y)LiyNb1-yBiy O3-Er0.005Yb0.005x(KNNLB:Er/Yb)。并對(duì)其微觀結(jié)構(gòu)、光學(xué)透光率和上轉(zhuǎn)換效應(yīng)等進(jìn)行了研究。結(jié)果表明:該透明陶瓷具有正交鈣鈦礦型結(jié)構(gòu),晶粒尺寸小于1μm,致密度較高,具有良好的透明性,當(dāng)y=0.06、x=0時(shí),在可見光范圍內(nèi)透過率可達(dá)到45%(樣品厚度為0.5 mm),紅外光區(qū)域透過率達(dá)到95%以上。但是隨著Yb3+離子摻雜量的增加,產(chǎn)生的雜相量變多,光學(xué)透光率因此呈明顯的下降趨勢(shì)。該體系透明陶瓷用氙燈光源激發(fā)(900 nm波長(zhǎng))即可以觀察到很明顯的上轉(zhuǎn)換效應(yīng)。(2)采用熱壓工藝制備出未摻雜的以及Eu3+摻雜的鈮酸鉀鈉基下轉(zhuǎn)換透明陶瓷K0.47Na0.47Li0.06Nb0.94Bi0.06O3-Eux(KNN:Eu)。陶瓷的斷面掃描電鏡表明這些陶瓷具有致密的微觀結(jié)構(gòu),XRD結(jié)果顯示制得的陶瓷都具有純相的鈣鈦礦結(jié)構(gòu)。對(duì)該體系透明陶瓷的光學(xué)透光度、室溫下的光致發(fā)光激發(fā)譜和發(fā)射譜研究表明:這些陶瓷具有良好的光學(xué)透光率,在可見光區(qū)域最高可以達(dá)到60%,而在紅外區(qū)域能夠達(dá)到接近100%。高摻雜濃度引起的離子空位和晶體缺陷的增加會(huì)導(dǎo)致這些陶瓷在可見光區(qū)域的透過率降低。對(duì)光致發(fā)光譜的分析表明,基于下轉(zhuǎn)換效應(yīng),這些陶瓷可以在近紫外和藍(lán)色光的激發(fā)下發(fā)射出很強(qiáng)的紅色熒光,其中與Eu3+的電偶極躍遷5D0-7F2相關(guān)的位于613 nm處的發(fā)射光尤其強(qiáng)烈。此外在晶體結(jié)構(gòu)的基礎(chǔ)上對(duì)陶瓷的光致發(fā)光特性進(jìn)行了分析,結(jié)果表明陶瓷的晶相轉(zhuǎn)變引起了發(fā)射譜線的Stark分裂。研究顯示這些透明陶瓷可以作為潛在的紅色熒光基底材料。(3)將堿土離子Sr2+、Ba2+引入KNN體系,采用熱壓工藝制得透明KNN基陶瓷[(K0.5Na0.5)1-2x(Sr0.75Ba0.25)x]0.93Li0.07Nb0.93Bi0.07O3(KNNLB:Sr/Ba)。對(duì)陶瓷的晶相結(jié)構(gòu)、壓電及介電性能進(jìn)行了初步的研究。結(jié)果表明微量的Sr2+、Ba2+摻雜可以有效的提高此陶瓷材料的電學(xué)性能。當(dāng)摻雜量x=0.025時(shí),此陶瓷擁有最佳的電學(xué)性能參數(shù):εr=1679,d33=151 pC/N和tanδ=0.026。然而過多的Sr2+/Ba2+摻雜量會(huì)引起雜相的產(chǎn)生,電學(xué)性能也會(huì)隨之迅速下降。
[Abstract]:KNN-based transparent ceramics with perovskite structure were successfully prepared by hot pressing sintering with sintering aids. The optical properties and fluorescence properties of rare-earth doped transparent ceramics were studied. The effect of Sr2 Ba2 on the dielectric and piezoelectric properties was studied. (1) the potassium and sodium niobate based up-conversion transparent ceramics K _ 0.5N _ (1-yn) Na _ (0.5) N _ (1-yBi) O _ (3) er 0.005Yb 0.005x KNLB: Er-YbO _ (1) were prepared by hot-pressing sintering process and Li and Bi as sintering aids. The microstructure of KNLB _ (1) -Y _ (2) O _ (3) O _ (3) O _ (3) er _ (0.005) Yb _ (0.005) Y _ (1) O _ (3) was studied. The optical transmittance and upconversion effect are studied. The results show that the transparent ceramic has orthogonal perovskite structure, grain size is less than 1 渭 m, high density and good transparency, when yr 0.06 X = 0:00, In the visible range, the transmittance can reach 45% (the thickness of the sample is 0. 5 mm ~ (-1), the transmittance of the infrared region is over 95%. However, with the increase of the doping amount of Yb3 ions, the amount of heterogeneity will increase. The optical transmittance of this system is obviously decreasing. The transparent ceramics in this system are excited by xenon lamp light source at 900nm) the obvious upconversion effect can be observed. (2) the undoped and Eu3 doped ceramics are prepared by hot pressing process. K0.47Na0.47Li0.06Nb0.94Bi0.06O3-EuxN = Eu.0.47Na0.47Li0.06Nb0.94Bi0.06O3-EuxN: Eu.The sectional scanning electron microscope of the ceramics shows that all of the ceramics have dense microstructure and the XRD results show that all of the ceramics have pure perovskite structure. The optical transmittance of the transparent ceramics in this system is also studied. The photoluminescence excitation and emission spectra at room temperature show that these ceramics have good optical transmittance. It can reach up to 60 in the visible region and close to 100 in the infrared region. The increase of ion vacancy and crystal defect caused by high doping concentration will reduce the transmittance of these ceramics in the visible region. Spectral analysis shows that, Based on the downconversion effect, these ceramics emit strong red fluorescence under the excitation of near ultraviolet and blue light. The emission at 613nm, which is related to the dipole transition of Eu3 5D0-7F2, is especially strong. The photoluminescence properties of the ceramics are analyzed based on the crystal structure. The results show that the crystal phase transition of the ceramics leads to the Stark splitting of the emission lines. The results show that these transparent ceramics can be used as the potential red fluorescent substrates to introduce alkali earth ion Sr2 Ba-2 into the KNN system. Transparent KNN based ceramics [K0.5Na0.51-2xFSr0.75Ba0.25x] 0.93Li0.07Nb0.93Bi0.07O3KNLBSr-Bax were prepared by hot pressing process. The crystal structure, piezoelectric and dielectric properties of the ceramics were studied. The results show that the electrical properties of the ceramics can be improved effectively by microamount of Sr2 Ba2 doping. This ceramic has the best electrical properties: 蔚 rn 1679 d 33C 151 pC/N and tan 未 O 0.026. However, excessive doping of Sr2 / Ba 2 leads to the generation of heterogenous phase, and the electrical properties decrease rapidly.
【學(xué)位授予單位】：常州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ174.758.23

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