Te-S-x掺杂型方钴矿材料热电性能及力学性能研究
发布时间：2019-05-28 20:38
【摘要】：热电材料是一种能够实现热能和电能之间相互转换的新型功能材料。方钴矿材料是一种性能优越的中温区块体热电材料,如何进一步提升方钴矿材料热电性能与力学强度已成为当前该领域重要的研究热点。本文围绕改善方钴矿材料电声协同调控为目的,采用固相反应结合放电等离子烧结技术合成了方钴矿化合物CoSb2.79Te0.16Se0.05-xSx及Co Sb2.79Te0.16P0.05-xSx(x=0,0.01,0.025,0.04,0.05),系统研究了Te-Se-S及Te-P-S两种掺杂对其微观结构及电热输运特性的影响。另外,还以方钴矿化合物Co Sb2.79Te0.16S0.05作为基体材料,采用超声分散及高能球磨技术使TiN纳米颗粒弥散分布其中获得复合方钴矿热电材料Co Sb2.79Te0.16S0.05+x vol%TiN(x=0.0,0.5,1.0),系统研究了纳米颗粒的引入对其微观结构及热电性能的影响,并探索了材料在不同温度条件下的力学性能演化规律。主要研究内容及结果如下:(1)所有方钴矿化合物CoSb2.79Te0.16Se0.05-xSx及CoSb2.79Te0.16P0.05-xSx(x=0,0.01,0.025,0.04,0.05)均为方钴矿纯相,其中化合物CoSb2.79Te0.16Se0.05-xSx化学成分均匀,表面厚度衬度一致,只有在样品x=0-0.025中存在少量的杂质相。而样品CoSb2.79Te0.16P0.05表面有比较明显的缺陷,随着S元素的掺入,样品表面缺陷明显减少。材料的电导率随着温度的升高而线性降低,赛贝克系数绝对值数随着温度的升高先升高而后由于本征激发作用略微下降。随着元素S掺杂量的增加,所有样品功率因子略微降低的同时热导率大幅度降低,表现出的ZT值也逐步提高。样品CoSb2.79Te0.16S0.05在800K的温度条件下取最低晶格热导率为1.14 Wm-1K-1,最高热电优值ZT为1.25。(2)对于微纳复合方钴矿材料Co Sb2.79Te0.16S0.05+x vol%TiN(x=0.0,0.5,1.0),均为晶内-晶间混合型结构特征,样品内部基本无空隙,致密度良好。随着温度的升高,所有样品电导率降低而塞贝克系数绝对值增大。随着TiN纳米颗粒体积分数的增加,热导率依次降低而热电优值基本保持不变。就力学性能而言,试样的线膨胀系数随着温度的升高而升高,复合了TiN纳米颗粒的试样在高温下的线膨胀系数升高幅度明显增大。所有试样的弯曲强度、压缩强度、断裂韧性均随着温度的升高总体呈现降低的趋势,常温下试样的弯曲强度、压缩强度、断裂韧性均大于500℃高温下的强度值。另外,方钴矿试样的力学性能随着复合TiN体积分数的增加而增强,结果表明经过纳米复合后的方钴矿的力学性能具有较为明显的优势。
[Abstract]:Thermoelectric material is a new type of functional material which can realize the conversion between heat energy and electric energy. Square cobalt ore material is a kind of bulk thermoelectric material in medium temperature zone with superior properties. How to further improve the thermoelectric properties and mechanical strength of square cobalt ore material has become an important research focus in this field. In this paper, the purpose of improving the electroacoustic cooperative control of square cobalt ore materials is to improve the electroacoustic synergistic regulation and control of square cobalt ore materials. The square cobalt compounds CoSb2.79Te0.16Se0.05-xSx and Co Sb2.79Te0.16P0.05-xSx were synthesized by solid phase reaction combined with spark plasma sintering (x 鈮，
本文编号：2487345
[Abstract]:Thermoelectric material is a new type of functional material which can realize the conversion between heat energy and electric energy. Square cobalt ore material is a kind of bulk thermoelectric material in medium temperature zone with superior properties. How to further improve the thermoelectric properties and mechanical strength of square cobalt ore material has become an important research focus in this field. In this paper, the purpose of improving the electroacoustic cooperative control of square cobalt ore materials is to improve the electroacoustic synergistic regulation and control of square cobalt ore materials. The square cobalt compounds CoSb2.79Te0.16Se0.05-xSx and Co Sb2.79Te0.16P0.05-xSx were synthesized by solid phase reaction combined with spark plasma sintering (x 鈮，
本文编号：2487345
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2487345.html
