【摘要】：熱電材料是一種能夠實現(xiàn)熱能和電能之間相互轉換的新型功能材料。方鈷礦材料是一種性能優(yōu)越的中溫區(qū)塊體熱電材料,如何進一步提升方鈷礦材料熱電性能與力學強度已成為當前該領域重要的研究熱點。本文圍繞改善方鈷礦材料電聲協(xié)同調控為目的,采用固相反應結合放電等離子燒結技術合成了方鈷礦化合物CoSb2.79Te0.16Se0.05-xSx及Co Sb2.79Te0.16P0.05-xSx(x=0,0.01,0.025,0.04,0.05),系統(tǒng)研究了Te-Se-S及Te-P-S兩種摻雜對其微觀結構及電熱輸運特性的影響。另外,還以方鈷礦化合物Co Sb2.79Te0.16S0.05作為基體材料,采用超聲分散及高能球磨技術使TiN納米顆粒彌散分布其中獲得復合方鈷礦熱電材料Co Sb2.79Te0.16S0.05+x vol%TiN(x=0.0,0.5,1.0),系統(tǒng)研究了納米顆粒的引入對其微觀結構及熱電性能的影響,并探索了材料在不同溫度條件下的力學性能演化規(guī)律。主要研究內容及結果如下:(1)所有方鈷礦化合物CoSb2.79Te0.16Se0.05-xSx及CoSb2.79Te0.16P0.05-xSx(x=0,0.01,0.025,0.04,0.05)均為方鈷礦純相,其中化合物CoSb2.79Te0.16Se0.05-xSx化學成分均勻,表面厚度襯度一致,只有在樣品x=0-0.025中存在少量的雜質相。而樣品CoSb2.79Te0.16P0.05表面有比較明顯的缺陷,隨著S元素的摻入,樣品表面缺陷明顯減少。材料的電導率隨著溫度的升高而線性降低,賽貝克系數絕對值數隨著溫度的升高先升高而后由于本征激發(fā)作用略微下降。隨著元素S摻雜量的增加,所有樣品功率因子略微降低的同時熱導率大幅度降低,表現(xiàn)出的ZT值也逐步提高。樣品CoSb2.79Te0.16S0.05在800K的溫度條件下取最低晶格熱導率為1.14 Wm-1K-1,最高熱電優(yōu)值ZT為1.25。(2)對于微納復合方鈷礦材料Co Sb2.79Te0.16S0.05+x vol%TiN(x=0.0,0.5,1.0),均為晶內-晶間混合型結構特征,樣品內部基本無空隙,致密度良好。隨著溫度的升高,所有樣品電導率降低而塞貝克系數絕對值增大。隨著TiN納米顆粒體積分數的增加,熱導率依次降低而熱電優(yōu)值基本保持不變。就力學性能而言,試樣的線膨脹系數隨著溫度的升高而升高,復合了TiN納米顆粒的試樣在高溫下的線膨脹系數升高幅度明顯增大。所有試樣的彎曲強度、壓縮強度、斷裂韌性均隨著溫度的升高總體呈現(xiàn)降低的趨勢,常溫下試樣的彎曲強度、壓縮強度、斷裂韌性均大于500℃高溫下的強度值。另外,方鈷礦試樣的力學性能隨著復合TiN體積分數的增加而增強,結果表明經過納米復合后的方鈷礦的力學性能具有較為明顯的優(yōu)勢。
[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，

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