摘要
采用快速热压烧结和退火处理工艺制备了多孔Yb_(x)Co_(4)Sb_(12)方钴矿材料,通过X-射线衍射仪和扫描电子显微镜对合金的组织结构进行表征,利用LSR-3塞贝克系数/电阻率测试仪测试合金的电性能,借助LFA457激光法导热分析仪测试合金的导热系数,并使用MCS-EMP霍尔效应测试系统测量合金室温下的载流子浓度和迁移率。利用相变过程中的体积变化,在未额外添加造孔剂的条件下,成功在填充方钴矿中原位构建了多孔结构。结果表明,退火处理有效消除了熔炼过程中残留的YbSb_(2)相,成功形成大量直径约10μm的孔洞,有效增强对声子的散射作用;随着Yb填充量的增加,退火后合金中孔洞结构的数量逐渐增多;当Yb填充量为0.300时达到填充上限,载流子浓度趋于饱和,电导率不再进一步增大。最终,在合金成分为Yb0.3Co4Sb12的多孔方钴矿中获得了提升的功率因子,其数值为51.46μW·cm^(-1)·K^(-2)(测试温度为773 K);同时,该成分的多孔方钴矿表现出最优的热电性能,最大热电优值为1.44(测试温度为873 K),平均热电优值为0.987(测试温度为300~873 K)。
Porous Yb_(x)Co_(4)Sb_(12)skutterudite materials were prepared by rapid hot-pressing sintering and annealing treatment.The microstructure of the alloy was characterized by X-ray diffraction and scanning electron microscopy.The electrical properties of the alloy were tested by LSR-3 Seebeck coefficient/resistivity tester.The thermal conductivity of the alloy were measured by LFA457 laser flash method thermal analyzer.The carrier concentration and mobility of the alloy at room temperature were measured by MCS-EMP Hall effect test system.The porous structures were successfully in-situ constructed in filled skutterudites without adding pore-forming agents by utilizing the volume change during the phase transformation.The results show that the annealing treatment effectively eliminates the residual YbSb_(2) phase remaining in the melting process and successfully forms a large number of pores with a diameter of about 10μm,effectively enhancing the scattering effect on phonons.With the increase of Yb filling amount,the number of pore structures in the alloy after annealing gradually increases.When the Yb filling amount reaches 0.300,the filling limit is reached,the carrier concentration tend to be saturated,and the electrical conductivity no longer increases further.Finally,in the porous skutterudite with the composition of Yb0.3Co_4Sb12,an enhanced power factor of 51.46μW·cm^(-1)·K^(-2)(tested at 773 K)was obtained.At the same time,the porous skutterudite with this composition shows the best thermoelectric performance,with a maximum figure of merit of 1.44(tested at 873 K)and an average figure of merit of 0.987(tested at 300-873 K).
作者
秦丹丹
王鑫
朱雪梅
QIN Dandan;WANG Xin;ZHU Xuemei(School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)
出处
《大连交通大学学报》
2025年第6期120-125,156,共7页
Journal of Dalian Jiaotong University
基金
国家自然科学基金项目(52201240)。
关键词
填充方钴矿
孔洞结构
Yb填充量
热电性能
filled skutterudite
pore structure
Yb filling amount
thermoelectricity
