熱電元件能將熱與電直接進行轉換，主要應用於廢熱回收和固態冷卻。在提倡綠能環保、節能減碳之今日，受到各界相當密切的關注及討論。CoSb3為方鈷礦(skutterudite)結構之熱電材料，具備良好的熱電性質。根據文獻研究指出於方鈷礦的結構中填入銦原子，能夠有效地降低CoSb3的晶格熱傳導係數，進而提升熱電性質。相圖為材料系統之基礎知識，是相變化、相生成以及微結構變化探討之重要依據。由於熱電材料的性質與微結構息息相關，因此熱電材料的相圖對於開發熱電材料十分重要。
Co-In-Sb三元熱電系統之相圖，為CoSb3中引入銦原子材料發展之重要基礎，然而目前Co-In-Sb三元熱電系統之相圖資料卻十分缺乏。本研究以實驗方法測定Co-In-Sb三元系統相圖，包含:(1) Co-In-Sb三元系統的650 ℃之等溫橫截面圖、(2) Co-In-Sb三元系統的850 ℃之等溫橫截面圖、(3) Co-In-Sb三元系統的CoSb3-InSb等值剖面圖、與(4) Co-In-Sb三元系統的液相線投影圖。
本研究由純元素製備三元Co-In-Sb合金，完全熔融後淬冷完成液相線投影圖合金製備，欲進行相平衡之合金在選定之溫度進行熱處理以達成相平衡。並對於三元合金樣品，進行金相、組成與XRD分析，以確定生成相之種類。依據實驗所得各種不同組成三元合金之平衡相之資料、以及組成二元系統之相圖，以測定(1)-(4)等四種相圖。
在850 ℃及650 ℃等溫橫截面圖有相似實驗結果，並未發現三元化合物；共確認三個三相區，分別為Co-CoSb-liquid、CoSb-CoSb2-liquid及CoSb2-CoSb3-liquid；其組成也分別於實驗中確立，兩個溫度之相邊界則有所不同。在CoSb3-InSb等值剖面圖共確立七個相區，分別為liquid、CoSb-liquid、CoSb-CoSb2-liquid、CoSb2-liquid、CoSb2-CoSb3-liquid、CoSb3-liquid及CoSb3-InSb。液相線投影圖中共有九個固化首要析出相，分別為Co、CoIn2、CoIn3、CoSb、CoSb2、CoSb3、InSb、In及Sb相區。在此三元系統中共存在七個三元不變反應，其中含有兩個class I、四個class II以及一個class III反應。

Thermoelectric devices can convert heat and electricity directly, and are used in solid state cooling and waste heat recovery. Owing to the worldwide focus on green energy and sustainable development, thermoelectric devices have attracted intensive research interests. CoSb3 is a skutterudite-structure compound of good thermoelectric properties. It has been reported that the thermoelectric properties of CoSb3 can be further enhanced by alloying with indium.
Phase diagrams are materials' basic information, and are useful for understanding of phase formation and transformation, and microstructural evolution of materials. The Co-In-Sb phase diagrams are thus fundamentally important for the development of CoSb3+Indium materials. However, there are limited Co-In-Sb phase diagram literatures available. This study determines the Co-In-Sb phase diagrams experimentally.. The efforts of this study include: (1) determination of the 650 ℃ isothermal section, (2) determination of the 850 ℃ isothermal section, (3) determination of CoSb3-InSb isoplethal section, and (4) determination of liquidus projection.
Ternary Co-In-Sb alloys were prepared with pure constituent elements and equilibrated at various temperatures. Their equilibrium phases were determined based on the results of metallographical, compositional and XRD analyses. The (1)-(3) phase diagrams were constructed based on the determined ternary phase equilibria results and available related phase diagrams. The primary solidification phases were determined from the as-quenched alloys and were used for the construction of liquidus projection.
The 850 ℃ and 650 oC isothermal sections are similar. No ternary compound is found in this study. Three tie-triangles, Co-CoSb-liquid, CoSb-CoSb2-liquid, and CoSb2-CoSb3-liquid are determined. There are seven phase regions in the CoSb3-InSb isoplethal section, which are liquid, CoSb-liquid, CoSb-CoSb2-liquid, CoSb2-liquid, CoSb2-CoSb3-liquid, CoSb3-liquid, and CoSb3-InSb. There are 9 primary solidification phases in the ternary Co-In-Sb ternary system, including Co, CoIn2, CoIn3, CoSb, CoSb2, CoSb3, InSb, In, and Sb. Seven invariant reactions involving in liquid phase include two class I, four class II, and one class III in the Co-In-Sb ternary system.

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