氢气、氮气下退火对Sb_(2)Te_(3)热电性能的影响  

The effect of annealing under hydrogen and nitrogen on the thermoelectric properties of Sb_2Te_3

作　　者：李美玲 王志帅 仲德晗 庞超 孙乃坤[1] LI Meiling;WANG Zhishuai;ZHONG Dehan;PANG Chao;SUN Naikun(School of Science,Shenyang Ligong University,Shenyang 110159,China)

机构地区：[1]沈阳理工大学理学院,沈阳110159

出　　处：《材料科学与工艺》2025年第2期51-56,66,共7页Materials Science and Technology

基　　金：沈阳理工大学光选科研团队建设项目(SLU-2022)。

摘　　要：Sb_(2)Te_(3)基合金机械加工性差,在热电器件中应用时需先粉碎,然后烧结成微米级尺寸的热电单元。针对常压烧结过程中Sb_(2)Te_(3)的挥发及氧化问题,本文提出一种在H_(2)、N_(2)气氛下退火热处理制备高性能Sb_(2)Te_(3)块体材料的新方法。首先将商业化的Sb_(2)Te_(3)母合金颗粒破碎,冷压成型后放入自制的高气压热处理装置,在550℃、18~52 MPa的高氢、氮压下烧结12 h。通过X射线衍射(XRD)及扫描电子显微镜(SEM)表征样品的结构及微结构,并通过差示扫描量热法(DSC)和热重(TG)分析样品在升温过程中的相变及质量变化。结果表明:H_(2)、N_(2)气氛下退火既可有效地抑制Te的挥发和Sb的氧化,改善微结构,也能够将少量的H或N原子引入到Sb_(2)Te_(3)的晶格中。退火处理的Sb_(2)Te_(3)块体在室温下表现出良好的热电性能,如1.4~2.0 W/(m·K)的低热导率和2250~2733 S/cm的高电导率。较低的热导率主要归因于晶格间隙中掺入H或N原子导致声子散射的增强。18 MPa氮气退火下的Sb_(2)Te_(3)的室温热导率约为2 W/(m·K),并具有最大的的室温功率因子(2301μW/(m·K^(2))),该值与单晶Sb_(2)Te_(3)的功率因子相近(2400μW/(m·K^(2)))。For utilization in thermoelectric modules,Sb_2Te_3-based alloys exhibit poor machinability,requiring pulverization followed by sintering into micron-sized units.To tackle the issues of volatilization and oxidation during the conventional sintering process,this study proposes a novel method for preparing high-performance Sb_2Te_3 bulk materials through annealing treatment in H_2 and N_2 atmopheres.The commercial Sb_2Te_3 particles were first crushed and cold-pressed into shapes,which were then placed in a self-designed high-pressure heat treatment apparatus.The resultant thin plates were annealed at 550℃for 12 hours under hydrogen and nitrogen pressure ranging from 18 to 52 MPa.X-ray diffraction(XRD)and scanning electron microscope(SEM)were employed to characterize the structure and microstructure of the samples.Additionally,differential scanning calorimetry(DSC)and thermal gravimetric(TG)curves were measured to analyze the phase transitions and mass loss during the heating process.The results show that annealing can effectively inhibit the volatilization of Te and the oxidation of Sb,improving the microstructure while introducing a small amount of H or N atoms into the matrix of Sb_2Te_3.The obtained Sb_2Te_3 bulks exhibit high room-temperature thermoelectric properties including a low thermal conductivity of~1.4-2.0 W/(m·K)and a high conductivity of 2250-2733 S/cm.The reduced thermal conductivity is primarily attributed to the enhanced phonon scattering caused by the incorporation of H or N atoms into the lattice sites.The 18 MPa-nitrogenized sample has a room-temperature thermal conductivity of~2 W/(m·K)and exhibited a maximal room-temperature power factor(PF)value of 2301μW/(m·K~2),which is close to that for single crystal Sb_2Te_3(~2400μW/(m·K~2)).

关 键 词：热电材料 Sb_(2)Te_(3) 退火 热导率 电导率 热电优值 

分 类 号：TB34[一般工业技术—材料科学与工程]