La掺杂P型Ce_(y)Fe_(3)CoSb_(12)热电材料及涂层的热电性能

Thermoelectric Properties of P-Type Ce_(y)Fe_(3)CoSb_(12)Thermoelectric Materials and Coatings Doped with La

采用熔融-退火-放电等离子烧结工艺合成P型CoSb_(3)基热电材料,研究Ce掺杂量对CoSb_(3)基热电材料显微组织和热电性能的影响,以及La掺杂对解耦热电关系的作用。结果表明,掺杂元素La和Ce降低了热导率,使La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)在整个测温区间的热导率保持在1 W/(m·K)左右,对应的最高热电优值在723 K时达到0.45。以磁控溅射法制备Al-Ni涂层,通过对溅射Al-Ni防护涂层的P型La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)材料热电性能进行测试,发现涂层的介入并未造成材料热电性能的衰退,且涂层与基底结合良好,元素分布均匀。以钎料Ag_(40)Cu_(60)对P型热电元件La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)与电极片Mo_(50)Cu_(50)接头进行焊接行为研究,发现界面处宏观结合效果良好。

During the use of fossil fuels,about two-thirds of the energy that is discharged into the environment in the form of waste heat are barely utilized and cause considerable environmental pollution and intense CO_(2)emission.Thermoelectric materials directly convert heat energy to electricity,thus,improving the utilization efficiency of fossil energy and reducing environmental pollution.Skutterudite CoSb_(3)has been widely studied as one of the materials for thermoelectric applications in the middle-temperature region.CoSb_(3)-based skutterudites are narrow bandgap semiconductors with a high-electrical conductivity and Seebeck coefficient.Meanwhile,thermoelectric performance of bulk CoSb_(3)has been considerably improved via doping and design of nano structures.Herein,P-type CoSb_(3)was synthesized via meltannealing-spark plasma sintering process.The effect of Ce-doping content on microstructure and thermoelectric properties of CoSb_(3)and the effect of La doping on decoupled thermoelectric performance were studied.Compared with Ce_(0.8)Fe_(3)CoSb_(12),the Seebeck coefficient of La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)increased with temperature,electrical resistivity decreased from 25μΩ·m to 15μΩ·m at 300 K,and power factor simulta neously increased from 480μW/(m·K2)to 642μW/(m·K2)at 673 K.The La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)thermal conductivity decreased with La or Ce doping to~1 W/(m·K),and the corresponding thermoelectric figure of merit reached 0.45 at 723 K in the temperature range from 300 K to 723 K.Al-Ni coating was deposited on the sintered bulk skutterudite via magnetron sputtering method.It was demonstrated that the coating did not degrade the thermoelectric performance,while the coating elements were uniformly distributed across the sintered bulk La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12).The welding behavior of P-type La_(0.1)Ce_(0.8)Fe_(3)CoSb_(12)was studied using a Ag_(40)Cu_(60)solder and a Mo_(50)Cu_(50)electrode sheet.The interface of this thermoelectric material was prone to cracking and pore formation,while the elements at the interface have not demonstrated remarkable diffusion.This indicates an efficiency of the interface bonding,which may be used in the fabrication technologies of thermoelectric devices.