t-ZrO_2对YSZ电解质材料力学性能和电性能的影响
摘要
众多学者对ZrO_2基固体电解质材料已进行了详尽的研究,虽然立方稳定氧化锆YSZ材料具有较高的电导率,但机械强度差、断裂韧性低。确保YSZ材料氧离子电导率的同时具有优良力学性能,以适应SOFC发展要求成为必然面临的课题。研制开发综合性能好,具有一定协同功能的电解质材料,必将受到越来越多材料工作者尤其是SOFC研究工作者的重视和开发。
本论文针对8YSZ电解质材料强度差、断裂韧性值低的问题,利用3Y-TZP韧性好,高温氧离子电导率较低的特点,在8YSZ电解质中加入3Y-TZP,通过对致密度、力学性能、电性能和微观结构等的测试,探讨t-ZrO_2的引入对力学性能的提高作用和对电性能的影响,找出最佳掺杂量和改性条件。
本论文通过实验证实:复相电解质材料最佳烧结制度为1450°C,保温2h。在YSZ电解质中加入3Y-TZP,由于Y的低扩散率,材料中Y并无严重均化现象,并可能形成了Y分布不均匀的核壳结构。材料的强度大大提高,断裂韧性略有改善,电导率稍有下降,但影响不大。当掺杂30wt% 3Y-TZP时,复相电解质材料的强度接近300MPa,较纯8YSZ提高一倍左右;韧性达到3.7MPa·m~(1/2),提高80%以上;1000°C时的电导率为0.11S·cm~(-1),较文献值降低不足10%,使材料具有良好的综合性能。
The electrolyte material based on ZrO2 had been researched in tensing by many scholars. The 8YSZ material that has a high electrical conductivity is widely used as electrolytes for solid oxide fuel cells (SOFCs). But its low strength and low fracture hampered the development of SOFCs. Enhancing the mechanical property with a proper electrical conductivity had become more and more important to meet the need of the development of SOFC.
In order to find a best method to improve the capability of YSZ electrolyte, the effects of 3Y-TZP additive on the density, strength, conductivity and microstructure were studied by means of X-ray diffraction and Vicker’s hardner. The strength and conductivity of YSZ electrolyte doped with different amount of 3Y-TZP were determined.
It was shown that the samples sintered at 1450°C for 2h were the best in properties. When 3Y-TZP powder was added to the YSZ system, the tetragonal phase ratio increased, which resulted in non-uniform doping of Y2O3 into the ZrO2 grains and abnormal grain growth occurred for the sample with a higher Y2O3 content. The results demonstrated that strength of the electrolyte increased remarkably, and the fracture toughness got improved. The electrical conductivity was lowered only slightly. The results displayed that the flexure strength and the fracture toughness of ceramics with 30% TZP reached 300MPa and 3.7MPa·m1/2 respectively, and the conductivity at 1000°C reached 0.11S·cm-1.
本论文针对8YSZ电解质材料强度差、断裂韧性值低的问题,利用3Y-TZP韧性好,高温氧离子电导率较低的特点,在8YSZ电解质中加入3Y-TZP,通过对致密度、力学性能、电性能和微观结构等的测试,探讨t-ZrO_2的引入对力学性能的提高作用和对电性能的影响,找出最佳掺杂量和改性条件。
本论文通过实验证实:复相电解质材料最佳烧结制度为1450°C,保温2h。在YSZ电解质中加入3Y-TZP,由于Y的低扩散率,材料中Y并无严重均化现象,并可能形成了Y分布不均匀的核壳结构。材料的强度大大提高,断裂韧性略有改善,电导率稍有下降,但影响不大。当掺杂30wt% 3Y-TZP时,复相电解质材料的强度接近300MPa,较纯8YSZ提高一倍左右;韧性达到3.7MPa·m~(1/2),提高80%以上;1000°C时的电导率为0.11S·cm~(-1),较文献值降低不足10%,使材料具有良好的综合性能。
The electrolyte material based on ZrO2 had been researched in tensing by many scholars. The 8YSZ material that has a high electrical conductivity is widely used as electrolytes for solid oxide fuel cells (SOFCs). But its low strength and low fracture hampered the development of SOFCs. Enhancing the mechanical property with a proper electrical conductivity had become more and more important to meet the need of the development of SOFC.
In order to find a best method to improve the capability of YSZ electrolyte, the effects of 3Y-TZP additive on the density, strength, conductivity and microstructure were studied by means of X-ray diffraction and Vicker’s hardner. The strength and conductivity of YSZ electrolyte doped with different amount of 3Y-TZP were determined.
It was shown that the samples sintered at 1450°C for 2h were the best in properties. When 3Y-TZP powder was added to the YSZ system, the tetragonal phase ratio increased, which resulted in non-uniform doping of Y2O3 into the ZrO2 grains and abnormal grain growth occurred for the sample with a higher Y2O3 content. The results demonstrated that strength of the electrolyte increased remarkably, and the fracture toughness got improved. The electrical conductivity was lowered only slightly. The results displayed that the flexure strength and the fracture toughness of ceramics with 30% TZP reached 300MPa and 3.7MPa·m1/2 respectively, and the conductivity at 1000°C reached 0.11S·cm-1.
引文
[1] 赵兵,卢立柱. 中低温固体氧化物燃料电池(SOFC)电解质材料. 稀土,1998,19(4):55-61
[2] 李英. ZrO_2 基固体电解质研究进展. 陶瓷学报,1997,18(4):223-227
[3] Badwal S P S. Stability of solid oxide fuel cell components. Solid States Ionics,2001,143:39
[4] Ji Yuan,Liu Jiang,Zhe L,et al. Study on the properties of Al2O3-doped (ZrO_2)0.92(Y2O3)0.08 electrolyte. Solid States Ionics,1999,126:227
[5] Feighery A J,Irvine J T S. Effect of alumina additions upon electrical properties of 8mol% yttria-stabilised zirconia. Solid States Ionics,1999,121:209
[6] 高濂,严东生,郭景坤. 固体氧化物燃料电池. 无机材料学报,1991,6(2):129-134
[7] Noriko Bamba,Yong-Ho Choa,Tohru Sekino,Koichi Niihara. Effects of nano-sized silicon carbide particulate on microstructure and ionic conductivity for 8 mol% yttria stabilized zirconia based nanocoposites. Solid States Ionics,1998,111:171-179
[8] Etsell T H,Flengas S N. The electrical properties of solid oxide electrolytes. Chem Rey,1970,70:339-376
[9] 穆柏春. 陶瓷材料的强韧化. 冶金工业出版社: 北京, 2002; 92-112.
[10] 江作昭. 陶瓷材料的强韧化. 清华大学, 北京, 1996.
[11] Dell R M,Hopper A. Solid Electrolytes. Academic Press: 1978.
[12] 蒋凯,张秀英,等. 固体氧化物燃料电池中的电解质. 稀有金属,2001,25(2):121-125
[13] N. Claussen,A. H. Heuer. Advances in Ceramics. American Ceramic Society: Colurnbus. OH., 1984; 12.
[14] M. Movi,T. Abe,H. Itoh,et al. Cubic-stabilized zirconia and alumina composites as electrolytes in planar type solid oxide fuel cells. Solid States Ionics,1994,74:152
[15] M. Owaga. Microstructures and mechanical properties of mullite-(yttria, magnesia- and cerai-stabilized) zirconia composites. J. Mater. Sci.,1997,32:5497-5503
[16] 陈平. 掺纳米 MgO 的 YSZ 固体电解质结构与性能研究. 贵州工业大学, 贵州, 2004.
[17] 梁广川,陈玉如. 燃料电池固体氧化物电解质研究进展. 硅酸盐通报,1999,18(5):39-45
[18] 郭景坤. 多相材料——值得注意的材料研究的新趋向. 世界科技研究与发展,2000,22(1):17-19
[19] A.G. Lanin,E.L. Muravin,V.P. Popov,V.N Turchin. Fractal analysis of cracks in alumina–zirconia composites J. Eur. Ceram. Soc,2003,23(3):469-479
[20] 许小红,任引哲,宋波,等. ZrO_2-SiC 复合材料的制备及导电特性的研究. 化学研究与应用,1998,10(4):396-400
[21] Masanori Hirano,Takayuki Oda,Kenji Ukai,Yasunobu Mizutani. Effect of Bi2O3 aditives in Sc stabilized zirconia electrolyte on a stability of crystal phase and electrolyte properties. Solid States Ionics,2003,158:215-223
[22] 郭景坤,诸培南. 复相陶瓷材料的设计原则. 硅酸盐学报,1996,24(1):7-13
[23] 唐学军. 二元互扩散系数及 YSZ 体系扩散系数的提取评估和数据库的建立. 北京科技大学, 北京, 2002.3.
[24] O. N. Grigoryev,S. A. Firstov,O. A. Babiy,et al. Effect of zirconia(3mol% yttria) additive on mechanical properties and strcture of alumina ceramics. J. Mater. Sci.,1994,29:4633-4638
[25] Masaki T. Mechanical properties of Y2O3-stabilized tetragonal ZrO_2 polycrystals after aging at high temperature. J. Am. Ceram. Soc,1986,69(7):519-522
[26] 果世驹. 粉末烧结理论. 冶金工业出版社: 北京, 2002.
[27] Kilner J A,Steel B C H. Nonstoi-Chiometric Oxides. Academic Press: New York, 1981.
[28] 申云军,黄校先. 氧化钇含量对 Al2O3/Y-TZP 复相陶瓷的影响. 无机材料学报,1996,11(2):259-263
[29] 冯建雅,沈志坚,王幼文,等. Y-TZP 陶瓷中钇的境界富集. 科学通报,1990,35(13):1031-1033
[30] 杜海燕,刘家臣,等. Y2O3 加入方式对 Y-TZP 材料结构与性能的影响. 硅酸盐学报,2000,28(6):553-556
[31] 李英,龚江宏. Y2O3 稳定 ZrO_2 材料离子电导率与温度的关系. 功能材料,1998,29(5):496-498
[32] N. Sawaguchi,H. Ogawa. Simulated diffusion of oxide ions in YO1.5-ZrO_2 at high temperature. Solid States Ionics,2000,128:183-189
[33] 郭新. 稳定化氧化锆的晶界导电模型. 物理学报,1998,47(8):1322-1338
[34] 利明,陈宗璋,向蓝翔,等. 偏析对氧化锆晶界电导的影响及提高晶界电导的几种方法. 硅酸盐通报,2004,23(3):77-80
[2] 李英. ZrO_2 基固体电解质研究进展. 陶瓷学报,1997,18(4):223-227
[3] Badwal S P S. Stability of solid oxide fuel cell components. Solid States Ionics,2001,143:39
[4] Ji Yuan,Liu Jiang,Zhe L,et al. Study on the properties of Al2O3-doped (ZrO_2)0.92(Y2O3)0.08 electrolyte. Solid States Ionics,1999,126:227
[5] Feighery A J,Irvine J T S. Effect of alumina additions upon electrical properties of 8mol% yttria-stabilised zirconia. Solid States Ionics,1999,121:209
[6] 高濂,严东生,郭景坤. 固体氧化物燃料电池. 无机材料学报,1991,6(2):129-134
[7] Noriko Bamba,Yong-Ho Choa,Tohru Sekino,Koichi Niihara. Effects of nano-sized silicon carbide particulate on microstructure and ionic conductivity for 8 mol% yttria stabilized zirconia based nanocoposites. Solid States Ionics,1998,111:171-179
[8] Etsell T H,Flengas S N. The electrical properties of solid oxide electrolytes. Chem Rey,1970,70:339-376
[9] 穆柏春. 陶瓷材料的强韧化. 冶金工业出版社: 北京, 2002; 92-112.
[10] 江作昭. 陶瓷材料的强韧化. 清华大学, 北京, 1996.
[11] Dell R M,Hopper A. Solid Electrolytes. Academic Press: 1978.
[12] 蒋凯,张秀英,等. 固体氧化物燃料电池中的电解质. 稀有金属,2001,25(2):121-125
[13] N. Claussen,A. H. Heuer. Advances in Ceramics. American Ceramic Society: Colurnbus. OH., 1984; 12.
[14] M. Movi,T. Abe,H. Itoh,et al. Cubic-stabilized zirconia and alumina composites as electrolytes in planar type solid oxide fuel cells. Solid States Ionics,1994,74:152
[15] M. Owaga. Microstructures and mechanical properties of mullite-(yttria, magnesia- and cerai-stabilized) zirconia composites. J. Mater. Sci.,1997,32:5497-5503
[16] 陈平. 掺纳米 MgO 的 YSZ 固体电解质结构与性能研究. 贵州工业大学, 贵州, 2004.
[17] 梁广川,陈玉如. 燃料电池固体氧化物电解质研究进展. 硅酸盐通报,1999,18(5):39-45
[18] 郭景坤. 多相材料——值得注意的材料研究的新趋向. 世界科技研究与发展,2000,22(1):17-19
[19] A.G. Lanin,E.L. Muravin,V.P. Popov,V.N Turchin. Fractal analysis of cracks in alumina–zirconia composites J. Eur. Ceram. Soc,2003,23(3):469-479
[20] 许小红,任引哲,宋波,等. ZrO_2-SiC 复合材料的制备及导电特性的研究. 化学研究与应用,1998,10(4):396-400
[21] Masanori Hirano,Takayuki Oda,Kenji Ukai,Yasunobu Mizutani. Effect of Bi2O3 aditives in Sc stabilized zirconia electrolyte on a stability of crystal phase and electrolyte properties. Solid States Ionics,2003,158:215-223
[22] 郭景坤,诸培南. 复相陶瓷材料的设计原则. 硅酸盐学报,1996,24(1):7-13
[23] 唐学军. 二元互扩散系数及 YSZ 体系扩散系数的提取评估和数据库的建立. 北京科技大学, 北京, 2002.3.
[24] O. N. Grigoryev,S. A. Firstov,O. A. Babiy,et al. Effect of zirconia(3mol% yttria) additive on mechanical properties and strcture of alumina ceramics. J. Mater. Sci.,1994,29:4633-4638
[25] Masaki T. Mechanical properties of Y2O3-stabilized tetragonal ZrO_2 polycrystals after aging at high temperature. J. Am. Ceram. Soc,1986,69(7):519-522
[26] 果世驹. 粉末烧结理论. 冶金工业出版社: 北京, 2002.
[27] Kilner J A,Steel B C H. Nonstoi-Chiometric Oxides. Academic Press: New York, 1981.
[28] 申云军,黄校先. 氧化钇含量对 Al2O3/Y-TZP 复相陶瓷的影响. 无机材料学报,1996,11(2):259-263
[29] 冯建雅,沈志坚,王幼文,等. Y-TZP 陶瓷中钇的境界富集. 科学通报,1990,35(13):1031-1033
[30] 杜海燕,刘家臣,等. Y2O3 加入方式对 Y-TZP 材料结构与性能的影响. 硅酸盐学报,2000,28(6):553-556
[31] 李英,龚江宏. Y2O3 稳定 ZrO_2 材料离子电导率与温度的关系. 功能材料,1998,29(5):496-498
[32] N. Sawaguchi,H. Ogawa. Simulated diffusion of oxide ions in YO1.5-ZrO_2 at high temperature. Solid States Ionics,2000,128:183-189
[33] 郭新. 稳定化氧化锆的晶界导电模型. 物理学报,1998,47(8):1322-1338
[34] 利明,陈宗璋,向蓝翔,等. 偏析对氧化锆晶界电导的影响及提高晶界电导的几种方法. 硅酸盐通报,2004,23(3):77-80