高温稳定型MLCC陶瓷的制备与研究
摘要
多层陶瓷电容器(MLCC)由于具有结构紧凑、体积小、比容高、介电损耗低、价格低廉等诸多优点,被广泛应用于各类电子设备。随着地下勘探、航空航天和军用移动通讯等设备的使用环境越来越恶劣,例如,用来探寻油气储量的电子设备,可能需要承受超过200℃的温度,这就要求再次扩大多层陶瓷电容器能正常工作的温度范围,因此,研究高温MLCC材料是目前多层陶瓷电容器发展的一个重要方向。
目前,BaTiO3(BT)以其极高的介电常数成为了MLCC的主要原料,但其居里温度过低的弱点限制着它的发展。和BaTiO3一样有着钙钛矿结构的钛酸铋钠(BNT)受到了人们的关注,但难以极化的特性却使得它无法批量化生产,而BNT与BT的复合材料(Bi0.5Na0.5)1-xBaxTiO3(BNBT)兼有两者的优点,有望成为高温可靠型MLCC产品的新材料。
本论文针对这些材料的特点,分别以BNBT-Ca(BNBCT),BNBT-La-Nb与(Bi0.5Na0.5)1-xCaxTiO3-Mn(BNCT-Mn)为基料,深入分析掺杂改性和工艺条件对陶瓷介电性能的影响。主要内容如下:
1.对BNBCT体系进行了三种助烧剂(硼硅酸盐、CuV2O6、CuBi2O4)掺杂,将陶瓷烧结温度降低到了1120℃,将并对降烧后的基料进行稀土掺杂研究,最终在烧结温度1120℃下获得了-55℃~ 250℃的宽温范围内,满足X9R标准的高温可靠型MLCC;
2.研制了BNBT-La-Nb和BNCT-Mn陶瓷材料,分别研究了主要成分和CaCO3掺杂对体系的影响,并研究了Fe2O3掺杂对BNCT-Mn烧结机制和介电性能的影响;
3.研究了工艺对陶瓷材料介电性能的影响。实验表明球磨时间越长,材料的损耗越小;相较于La离子的内掺杂,外掺杂的BNBT-La-Nb体系的容温特性得到了更大的改善。
Multilayer ceramic capacitors (MLCCs) have been widely used in electronic equipments, attributed to compact structure, small size, high specific volume, low dielectric loss and low cost. Harsh environments, such as underground exploration, aerospace and military, require MLCCs to extend their working temperature, at the same time maintain good electrical properties. For example, the working temperature for oil exploring and gas reserves must be raised above 200℃. Therefore, developments of high-temperature capacitors are of great importance.
Currently, BaTiO3 (BT) is one of the most important materials for MLCC products because of its high dielectric constant, but the low Curie temperature limits its applications in high-temperature capacitors. Bi0.5Na0.5TiO3 (BNT), which has a high Curie temperature of 320℃and the same perovskite structure with BT, has attracted much attention. However, it is difficult to be practical used due to polarization problems. The solid solution of BT and BNT (BNBT), which has advantages of BT and BNT, is hopeful to to become a new material for high-temperature stable MLCC products. According to the characteristics of these materials, the dielectric properties of the systems affected by the dopings and sintering processes were deeply studied. The systems were on the base of BNBCT,BNBT-La-Nb and BNCT-Mn materials. The main results are as follows:
1. Three sintering aids (Boron- silicate, CuV2O6, CuBi2O4) were doped to BNBCT ceramics and the sintering temperature was reduced to 1120℃. After that, the effects of rare-earth elements doping on the dielectric properties of low-temperature sintered BNBCT ceramics were studied. Finally, high-temperatiure capacitor materials which meet the X9R specification in a wide temperature range from -55℃to 250℃were achieved.
2. The effects of major components and CaCO3 on the microstructure and dielectric properties of BNBT-La-Nb and BNCT-Mn system were investigated. Moreover, the addition of Fe2O3 on the sintering mechanism and dielectric properties of BNCT-Mn system were investigated.
3. The effects of ball milling time and doping methods on the microstructure and dielectric properties of multi-layer ceramic capacitors are investigated in detail. The results revealed that a longer milling time would bring to a lower dielectric loss. The temperature characteristic of capacitance for La outside-doped BNBT-La-Nb system was greatly improved, compared with La inside-doped system.
目前,BaTiO3(BT)以其极高的介电常数成为了MLCC的主要原料,但其居里温度过低的弱点限制着它的发展。和BaTiO3一样有着钙钛矿结构的钛酸铋钠(BNT)受到了人们的关注,但难以极化的特性却使得它无法批量化生产,而BNT与BT的复合材料(Bi0.5Na0.5)1-xBaxTiO3(BNBT)兼有两者的优点,有望成为高温可靠型MLCC产品的新材料。
本论文针对这些材料的特点,分别以BNBT-Ca(BNBCT),BNBT-La-Nb与(Bi0.5Na0.5)1-xCaxTiO3-Mn(BNCT-Mn)为基料,深入分析掺杂改性和工艺条件对陶瓷介电性能的影响。主要内容如下:
1.对BNBCT体系进行了三种助烧剂(硼硅酸盐、CuV2O6、CuBi2O4)掺杂,将陶瓷烧结温度降低到了1120℃,将并对降烧后的基料进行稀土掺杂研究,最终在烧结温度1120℃下获得了-55℃~ 250℃的宽温范围内,满足X9R标准的高温可靠型MLCC;
2.研制了BNBT-La-Nb和BNCT-Mn陶瓷材料,分别研究了主要成分和CaCO3掺杂对体系的影响,并研究了Fe2O3掺杂对BNCT-Mn烧结机制和介电性能的影响;
3.研究了工艺对陶瓷材料介电性能的影响。实验表明球磨时间越长,材料的损耗越小;相较于La离子的内掺杂,外掺杂的BNBT-La-Nb体系的容温特性得到了更大的改善。
Multilayer ceramic capacitors (MLCCs) have been widely used in electronic equipments, attributed to compact structure, small size, high specific volume, low dielectric loss and low cost. Harsh environments, such as underground exploration, aerospace and military, require MLCCs to extend their working temperature, at the same time maintain good electrical properties. For example, the working temperature for oil exploring and gas reserves must be raised above 200℃. Therefore, developments of high-temperature capacitors are of great importance.
Currently, BaTiO3 (BT) is one of the most important materials for MLCC products because of its high dielectric constant, but the low Curie temperature limits its applications in high-temperature capacitors. Bi0.5Na0.5TiO3 (BNT), which has a high Curie temperature of 320℃and the same perovskite structure with BT, has attracted much attention. However, it is difficult to be practical used due to polarization problems. The solid solution of BT and BNT (BNBT), which has advantages of BT and BNT, is hopeful to to become a new material for high-temperature stable MLCC products. According to the characteristics of these materials, the dielectric properties of the systems affected by the dopings and sintering processes were deeply studied. The systems were on the base of BNBCT,BNBT-La-Nb and BNCT-Mn materials. The main results are as follows:
1. Three sintering aids (Boron- silicate, CuV2O6, CuBi2O4) were doped to BNBCT ceramics and the sintering temperature was reduced to 1120℃. After that, the effects of rare-earth elements doping on the dielectric properties of low-temperature sintered BNBCT ceramics were studied. Finally, high-temperatiure capacitor materials which meet the X9R specification in a wide temperature range from -55℃to 250℃were achieved.
2. The effects of major components and CaCO3 on the microstructure and dielectric properties of BNBT-La-Nb and BNCT-Mn system were investigated. Moreover, the addition of Fe2O3 on the sintering mechanism and dielectric properties of BNCT-Mn system were investigated.
3. The effects of ball milling time and doping methods on the microstructure and dielectric properties of multi-layer ceramic capacitors are investigated in detail. The results revealed that a longer milling time would bring to a lower dielectric loss. The temperature characteristic of capacitance for La outside-doped BNBT-La-Nb system was greatly improved, compared with La inside-doped system.
引文
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[4] Boufrou B D G, Raveau B. Tetragonal Tungsten Bronze Niobate, K0.2Sr0.4NbO3: A New Material for Capacitors with Flat Dielectric Curves [J]. Journal of the American Ceramic Society, 1991, 74(11):2809-2814
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[6] Gui Z L W Y, Li L T. Lead-based relaxor fen oelectric ceramics for high performance low firing MLCs [J]. IEEE International Symposium on Applications of Ferroelectrics, 1996:409-412
[7] H M G. New PLZT dielectric for use in characterisitic X7R multilayer ceramic capacitors [J]. IEEE Transactions on Components, Hybrids and Manufacturing Technology, 1983, 6(4):372-376
[8] Natarajan R D J P. Role of Mn in controlling the dielectric loss and ageing effect in Pb(Zn1/3Nb2/3)O3-Pb(Fe2/3W1/3)O3-Pb(Fe1/2Nb1/2)O3 [J]. Journal of Materials Science, 1998, 33(8):1991-1995
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[15]王强.片式元件小型化低成本方向不变国内企业面临新一轮整合[J].电子元件与材料, 2008, 27(3)
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[20] Tang B Z S, Zhou X, et al. Regression Analysis for Complex Doping of X8R Ceramics Based on Uniform Design [J]. Journal of Electronic Materials, 2007, 36(10):1383-1388
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[23]巴哈提古丽,毛涛涛,杨泽玮.复合掺杂BaTiO3基介电陶瓷的介电性能研究[J].中央民族大学学报(自然科学版), 2006, 15(1):40-43
[24]郭秀盈,肖谧,杜文娟.复合钙钛矿型介质陶瓷材料的研究进展[J].电子元件与材料, 2006, 25:1-4
[25]张其土,张校平,李斌. BaTiO3基无铅高压陶瓷电容器材料性能的研究[J].电子元件与材料, 2005, 24(12):38-41
[26]钟宜志. BT-BNT介电陶瓷之介电性质及显微结构之研究:[硕士学位论文] [J].台湾:成功大学,2008.
[27] Takenaka.T. Piezoelectric propertiesof some lead- free ferroelectric ceramics [J]. Ferroelectrics, 1992, 30:87-98
[28] Tadashi Takenaka K-i M K S. (Na1/2Bi1/2)TiO3 systemfor lead2free piezoelectric ceramic [J]. Journal of Applied Physics, 1992, 30(9B):2236-2239
[29] K. T T S. Dielectric,piezoelectric and pyroelectric properties of (Na1/2Bi1/2)TiO3 - based ceramic [J]. Terroelectrics, 1989, 95 (153-156)
[30]黄荣夏,周桃生,顾豪爽,等.直接反应烧结法制备(Bi0.5Na0.5) (1-x)BaxTiO3系无铅压电陶瓷的性能研究[J].功能材料, 2007, 38(2):224-226
[31] J M W. Double Hysteresis Loop of BaTiO3 at the Curie Point. [J]. Physical Review, 1953, 91(3):513
[32] Lei Z O P T, Antonio F, et al. Comment on the use of calcium as a dopant in X8R BaTiO3-based ceramics [J]. Applied Physics Letters, 2007, 90(14):142914
[33] Okazaki K K S. Microstructure and Dielectric Properties of high Permittivity Ceramics [J]. J. Ceram. Assoc. Japan, 1965, 73(3-11):60-66
[34]罗金玲,周志刚.亚纳米铁电陶瓷介电性能的粒度效应[J].无机材料学报, 1995, 10(02):209-213
[35] Kuwabara M, Matsuda H, Kurata N, et al. Shift of the Curie Point of Barium Titanate Ceramics with Sintering Temperature. Journal of the American Ceramic Society, 1997, 80(10): 2590-2596.
[36] Sakabe Y W N, Hiramatsu T, et al. Dielectric properties of fine-grained BaTiO3 ceramics doped with CaO [J]. Japanese Journal of Applied Physics, 2002, 41(11 B):6922-6925
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[2]闫晓金,陈永真.陶瓷电容器在电力电子线路中的应用[J].电源世界, 2007, 3:74-75
[3]陈永真,李丽.大容量陶瓷电容器在高频整流滤波中的应用[J].电源世界, 2007, 5:69-72
[4] Boufrou B D G, Raveau B. Tetragonal Tungsten Bronze Niobate, K0.2Sr0.4NbO3: A New Material for Capacitors with Flat Dielectric Curves [J]. Journal of the American Ceramic Society, 1991, 74(11):2809-2814
[5] Tribotte B H J M, Desgardin G. K2Sr4Nb10O30-based dielectric ceramics having the tetragonal tungsten bronze structure and temperature-stable high permittivity [J]. Journal of the European Ceramic Society, 1999, 19(6-7):1105-1109
[6] Gui Z L W Y, Li L T. Lead-based relaxor fen oelectric ceramics for high performance low firing MLCs [J]. IEEE International Symposium on Applications of Ferroelectrics, 1996:409-412
[7] H M G. New PLZT dielectric for use in characterisitic X7R multilayer ceramic capacitors [J]. IEEE Transactions on Components, Hybrids and Manufacturing Technology, 1983, 6(4):372-376
[8] Natarajan R D J P. Role of Mn in controlling the dielectric loss and ageing effect in Pb(Zn1/3Nb2/3)O3-Pb(Fe2/3W1/3)O3-Pb(Fe1/2Nb1/2)O3 [J]. Journal of Materials Science, 1998, 33(8):1991-1995
[9] Villegas M F J F, Moure C, et al. Preparation, microstructural development and dielectric properties of Pb(Mg1/3Nb2/3)O3-Pb(TiXZr1-X)O3 multilayer ceramic capacitors [J]. Journal of Materials Science, 1994, 29(19):4999-5004
[10] Natarajan R D J P. Influence of Li addition on the sintering and dielectric properties of PNN-PMW-PT relaxor ferroelectrics [J]. Materials Research Society Symposium-Proceedings, 1997, 453(Solid-State Chemistry of Inorganic Materials):473-481
[11]邓湘云,李建保,王晓慧. MLCC的发展趋势及在军用电子设备中的应用[J].电子元件与材料, 2006, 25:1-6
[12]范跃农,胡鸿豪,曹良足.陶瓷电容器的发展趋势[J].中国陶瓷, 2008, 44(5):14-15
[13]张宇,张承琚,王永春.多层陶瓷电容器及其发展趋势[J].江西科学, 2005,04,
[14]王俊波.多层陶瓷电容器的技术现状及未来发展趋势[J].绝缘材料, 2008, 41(3):23-25
[15]王强.片式元件小型化低成本方向不变国内企业面临新一轮整合[J].电子元件与材料, 2008, 27(3)
[16]太阳诱电.太阳诱电推出兼顾小尺寸及大容量的积层陶瓷电容器[J].电子元件与材料, 2009, 28(11) 75-76
[17]丛秋波.实现了大容量化的片状层压陶瓷电容器[J]. EDN CHINA电子设计技术, 2004, 11(3):24-26
[18]陈祥冲,黄新友.贱金属内电极多层陶瓷电容器产业研发现[J].新材料产业, 2005, 3:57-60
[19]齐晓敏,滕,陈堃.多层陶瓷电容器Ni电极与BaTiO3陶瓷的共烧研究[J].陶瓷学报, 2007, 28:334-337
[20] Tang B Z S, Zhou X, et al. Regression Analysis for Complex Doping of X8R Ceramics Based on Uniform Design [J]. Journal of Electronic Materials, 2007, 36(10):1383-1388
[21]苗海龙.中国MLCC研发与制造技术跨越国际化新高度[J].电子元件与材料, 2008, 27:23
[22] J M W. Double Hysteresis Loop of BaTiO3 at the Curie Point [J]. Physical Review, 1953, 91(3):513
[23]巴哈提古丽,毛涛涛,杨泽玮.复合掺杂BaTiO3基介电陶瓷的介电性能研究[J].中央民族大学学报(自然科学版), 2006, 15(1):40-43
[24]郭秀盈,肖谧,杜文娟.复合钙钛矿型介质陶瓷材料的研究进展[J].电子元件与材料, 2006, 25:1-4
[25]张其土,张校平,李斌. BaTiO3基无铅高压陶瓷电容器材料性能的研究[J].电子元件与材料, 2005, 24(12):38-41
[26]钟宜志. BT-BNT介电陶瓷之介电性质及显微结构之研究:[硕士学位论文] [J].台湾:成功大学,2008.
[27] Takenaka.T. Piezoelectric propertiesof some lead- free ferroelectric ceramics [J]. Ferroelectrics, 1992, 30:87-98
[28] Tadashi Takenaka K-i M K S. (Na1/2Bi1/2)TiO3 systemfor lead2free piezoelectric ceramic [J]. Journal of Applied Physics, 1992, 30(9B):2236-2239
[29] K. T T S. Dielectric,piezoelectric and pyroelectric properties of (Na1/2Bi1/2)TiO3 - based ceramic [J]. Terroelectrics, 1989, 95 (153-156)
[30]黄荣夏,周桃生,顾豪爽,等.直接反应烧结法制备(Bi0.5Na0.5) (1-x)BaxTiO3系无铅压电陶瓷的性能研究[J].功能材料, 2007, 38(2):224-226
[31] J M W. Double Hysteresis Loop of BaTiO3 at the Curie Point. [J]. Physical Review, 1953, 91(3):513
[32] Lei Z O P T, Antonio F, et al. Comment on the use of calcium as a dopant in X8R BaTiO3-based ceramics [J]. Applied Physics Letters, 2007, 90(14):142914
[33] Okazaki K K S. Microstructure and Dielectric Properties of high Permittivity Ceramics [J]. J. Ceram. Assoc. Japan, 1965, 73(3-11):60-66
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