B位掺杂对固体氧化物燃料电池连接材料La_(0.85)Sr_(0.15)CrO_3性能的影响

Effect of B-site doping on properties of La_(0.85)Sr_(0.15)CrO_3 forsolid oxide fuel cell interconnector

研究La0．85Sr0．15CrO3B位（Cr位）掺杂不同的金属离子（Ni、Cu、Co、Ti、Ni＋Co）的烧结性能、热膨胀和电子电导率．实验发现：离子掺杂可以降低La0．85Sr0．15CrO3的烧结温度；掺杂Ni对提高系统烧结性能最有效，La0．85Sr0．15Cr0.95Ni0.05O3的相对密度可达到94％；掺杂Co或者Cu能提高La0．85Sr0．15CrO3的热膨胀系数，而Ni和Ti掺杂则有相反作用．所有试样在300～1000℃具有线性热膨胀性，La0.85，Sr0.15，Cr0.95，Ni0.02Co0.02，在1000℃空气气氛中的热膨胀系数为10．6×10^-6／℃，和摩尔分数为8％的Y2O3稳定的ZrO2（8YSZ）电解质的热膨胀系数相匹配．与B位一元掺杂的La0．85Sr0．15CrO3试样相比，La0．85Sr0．15Cr0.95Ni0.02Co0.02O3在675～850℃温度范围内显示出更高的电子电导率．

La0. 85 Sr0. 15 Cr0. 95 M0. 05 O3 （ M = Ni, Cu, Co, Ti, Ni ＋ Co） perovskites were prepared by solid-state reaction to investigate the effect of B-site doping on sinterability, thermal expansion and electrical conductivity. Ion doping can lower the sintering temperature of La0. 85Sr0.15 CrO3. Among four metals, Ni is the most effective to improve the sinterability of the system. The relative density of La0.85 Sr0. 25 Cr0. 95Ni0.05O3 can reach 94%. The doping of Co and Cu increases the thermal expansion coefficient （ TEC ） of La0.85 Sr0.15 CrO3 while Ti and Ni doping has a negative effect. Linear thermal expansion behavior is observed on all samples when they are heated from 300℃ to 1 000 ℃. The TEC of La0.85Sr0.15Cr0.95Ni0.02Co0.02O3 is 10. 6 × 10^-6℃ at 1 000℃ in air, which is co le with that of ZrO2（8YSZ） electrolyte stabilized with 8% of Y2O3. Compared with B-site unary-doped La0.85Sr0. 15CrO3, La0.85Sr0.15Cr0.95Ni0.02Co0.02O3 show the higher electrical conductivity between 675 and 850℃.