添加錳離子對鈦酸鋇微結構及性質之影響

本研究利用傳統固態反應法，以BaCO3+TiO2添加不同價數錳氧化物(MnO、Mn2O3、Mn3O4)形成Ba(Ti1-xMnx)O3，配方比分別為x = 0.15、0.3、0.4、0.5，在1450oC持溫兩小時燒結，冷卻至室溫可得到介穩態六方晶鈦酸鋇相，並利用介電性質檢測、XRD、SEM和TEM等分析方法，分析添加不同價數及不同比例之錳氧化物對於六方晶鈦酸鋇相變化、微結構及介電性質之影響。錳氧化物的添加皆會使六方晶鈦酸鋇晶格常數縮小，且隨著錳氧化物量的增加，其晶粒由等軸狀漸漸變為平板狀，當添加量達x = 0.5時，會使其結構改變並產生12R-Ba(Ti1-xMnx)O3相，其結構如同BaFeO3(JCPDS 74-0646)，晶粒呈現12R-6H-12R次序堆積。添加Mn2+離子則會在晶界產生(Ba2-yMny)TiO4相。針對添加x = 0.5的Mn3O4作TEM分析，分析其結構之差別，並觀察到有差排、疊差、超晶格結構等缺陷。介電性質方面，添加x = 0.3之Mn3O4具有較高的Q•f值，可達18344 GHz。

關鍵字

六方晶鈦酸鋇；錳氧化物；相變化；電子顯微鏡

並列摘要

The Ba(Ti1-xMnx)O3 ceramics were synthesized by traditional solid-state reaction with the raw powders BaCO3, TiO2, and MnO (or Mn2O3, or Mn3O4). The compositions on the Ba(Ti1-xMnx)O3 samples were x = 0.15, 0.3, 0.4 and 0.5, and sintered at 1450oC for 2hr, then cooled to room temperature to obtain metastable hexagonal barium titanate. The Ba(Ti1-xMnx)O3 samples were analyzed by measuring dielectric parameters, XRD, SEM and TEM on the microstructures and properties. The results showed that added three manganese oxides were similar, (1) lattice parameters decrease as x concentrations increase form x = 0.15 to x = 0.5, (2) 12R Ba(Ti1-xMnx)O3 structure was similar to BaFeO3 structure at x = 0.5. The grain sharps changed from isotropic to plate-like with increaseing x concentration. For adding MnO samples, the (Ba2-yMny)TiO4 phase was detected on the grain boundary due to excess divalence Ba2+ and Mn2+ ions. The TEM analysis was focused on the Ba(Ti0.5Mn0.5)O3 specimens to identify the structure and obtain some defects, i.e., dislocation, stacking fault, and superlattices. For dielectric properties, the quality factor (Q•f) reaches the maximum value (18344 GHz) at x = 0.3 for adding Mn3O4 system.

並列關鍵字

BaTiO3 ； Hexagonal ； Dielectric resonator ； Microwave dielectric properties

參考文獻

[1] D. E. Rase, and R. Roy, “Phase equilibria in the system BaO-TiO2,” J. Am.Ceram. Soc., 38 [1-2] 102-113 (1955).

[2] B. C. LaCourse, and V. R. W. Amarakoon, “Characterization of the firing schedule for positive temperature coefficient of resistance BaTiO3,” J. Am. Ceram. Soc., 78 [12] 3352-3356 (1995).

[4] H. M. O'bryan, “Phase equilibria in the TiO2-rich region of the system BaO-TiO2,” J. Am. Ceram. Soc., 57 [12] 522-526 (1974).

[5] K. W. Kirby, and B. A. Wechsler, “Phase relations in the BaTiO3-TiO2 system,” J. Am. Ceram. Soc., 74 [8] 1841–1947 (1991).

[6] H. Arend, and L. Kihlborg, “Phase composition of reduced and reoxidised barium titanate,” J. Am. Ceram. Soc., 52[2] 63–65 (1969).

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添加錳離子對鈦酸鋇微結構及性質之影響

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