半赫斯勒結構鈦鈷錫與鈦鎳錫熱電材料 之開發研究

Development of half-Heusler TiCoSn and TiNiSn Thermoelectric Materials

楊智詠(Chih-Yuan Yang)

指導教授 ： 吳新明

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

本研究選取Ti-Co-Sn與Ti-Ni-Sn合金系統，針對成份為TixCoySn100-x(x=20~60, y=20~60)與TixCoySn100-x(x=20~60, y=20~60)之各成份進行機械合金化球磨及真空熱壓，探討生成單一半赫斯勒TiCoSn與TiNiSn合金之可行性及量測其熱電性質。對於Ti-Co-Sn各成份球磨後，發現初始成份為化學計量Ti1Co1Sn1成份經球磨後可得到半赫斯勒結構之TiCoSn相，而偏離Ti1Co1Sn1成份則會生成非晶、TiCo2Sn赫斯勒相、CoSn2相、或TiCo2Sn與TiCo之混合物。將可形成單一TiCoSn相之球磨Ti1Co1Sn1粉末藉由真空熱壓製成塊材，再進行緻密化處理，分別探討熱壓及熱壓+緻密化處理對於生成TiCoSn赫斯勒結構相及其熱電性質之影響，XRD結果發現熱壓及熱壓後再經緻密化處理皆可獲得單一相之TiCoSn塊材。熱電量測結果顯示熱壓塊材其功率因子為0.7897 μW/K2㎝，復經緻密化熱處理之塊材其功率因子為1.7455 μW/K2cm。對Ti-Ni-Sn合金系統進行球磨，Ti1Ni1Sn1化學計量成份可生成TiNiSn與TiNi化合物，而偏離Ti1Ni1Sn1成份則會形成單一相之非晶、Ni3Sn4、TiNi、或TiNi2Sn+TiNi、TiNiSn+TiNi、TiNiSn+TiNi+Ti、與Ni3Sn4+Ni混合物。將球磨後之Ti1Ni1Sn1成份粉末熱壓所得之塊材其功率因子為0.3413 μW/K2cm。

關鍵字

半赫斯勒結構 ； 鈦鈷錫 ； 鈦鎳錫 ； 熱電性 ； 機械合金製程

並列摘要

This study utilized mechanical alloying and vacuum hot-pressing techniques to investigate the feasibility of obtaining a single phase of TiCoSn or TiNiSn alloy with half-Hesuler structure and measure their thermoelectric properties from initial compositions of TixCoySn100-x (x=20~60, y=20~60) and TixCoySn100-x (x=20~60, y=20~60) in Ti-Co-Sn and Ti-Ni-Sn system. For the Ti-Co-Sn system, it is found that the initial stoichimetric Ti1Co1Sn1 composition after milling can produce single half-Heusler TiCoSn phase and for those compositions that deviate from Ti1Co1Sn1 composition, milling can produce single amorphous, TiCo2Sn Heusler phase, TiCo2Sn, or TiCo2Sn and TiCo mixture, respectively. The milled Ti1Co1Sn1 powders were subjected to vacuum hot-pressing and vacuum hot-pressing plus subsequent densification treatment, respectively, to produce bulk materials with different density. The XRD results indicate that a single phase of bulk TiCoSn material can be produced by these processes. Thermoelectric measurements reveal the maximum power factors for the hot-pressed and hot-pressed plus densification bulk materials are 0.7897 μW/K2cm and 1.7455 μW/K2cm, respectively. For the Ti-Ni-Sn system, milling on the stoichiometric Ti1Ni1Sn1 composition can produce TiNiSn and TiNi compound mixture. Milling on the compositions in the neighborhood of Ti1Ni1Sn1 can produce a single phase of amorphous, Ni3Sn4, TiNi, or mixtures of TiNi2Sn+TiN, TiNiSn+TiNi, TiNiSn+TiNi+Ti, and Ni3Sn4+Ni. The power factor of the hot-pressed Ti1Ni1Sn1 bulk material is measured to be 0.3413 μW/K2cm.

並列關鍵字

half-Hesuler structure ； TiCoSn ； TiNiSn ； thermoelectricity ； mechanical

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