現今能源危機是全球共同問題之一，研究替代能源及提高能源材料使用效率，都是現今能源發展的方向。熱電材料是可以直接轉換熱與電兩種不同的能量，將廢熱轉為電能提升能源使用效率，因此在能源研究上受到很大的關注及討論。AgBiSe2 為立方I-V-VI2之結構的熱電材料，具有極端非和諧性的晶格震動，而導致極低的熱導率(κ=κl+κe)，因此具有良好的熱電性質。相圖為材料系統之基礎，是了解材料相轉變及內部結構變化資訊之重要來源。對於熱電材料而言，其結構與性質十分相關，因此必須以相圖為基礎來研究熱電材料。Ag-Bi-Se三元系統相圖及AgBiSe2-GeSe擬二元相圖為研究Ag-Bi-Se-Ge熱電系統之重要基礎，然而目前文獻中並無Ag-Bi-Se和Ag-Ge-Se三元系統相圖及AgBiSe2-GeSe和AgBiSe2-AgGeSe2擬二元相圖。因此本研究主要以實驗與分析來建立上述三元系統及擬二元相圖，並依據相圖找出I-V-VI2穩定存在之相區，進行熱電性質的量測。本研究的工作將包括: (1) 以實驗測定Ag-Bi-Se三元系統之液相線投影圖、(2) 以實驗測定Ag-Bi-Se三元系統和AgBiSe2-GeSe擬二元系統的500˚C之等溫橫截面圖、(3) 於上述研究中找出I-V-VI2之結構合金，(4)量測AgBiSe2之熱電性質以及四元合金AgBiSe2摻雜GeSe之熱電性質。

Energy crisis is one of the world-wide issues nowadays. Recently, the energy developments focus on searching alternative energy and enhance the efficiency of energy materials. Thermoelectric material has attracted great attention because it can directly convert waste heat into electricity, resulting in increasing the energy usage efficiency. The I-V-VI2 AgBiSe2, which adopts cubic structure, is a promising thermoelectric material and is known to exhibit nonhomogeneous lattice vibration that leads to low thermal conductivity. Phase diagrams are basic yet essential materials information that probe the thermodynamically phase stability behaviors. With an aid of phase diagram and microstructural evolution, the thermoelectric properties can be optimized. Herein, we aim to determine the ternary phase diagram of Ag-Bi-Se system and Ag-Ge-Se system and the Pseudobinary phase diagram of AgBiSe2-GeSe. The efforts of this study include: (1) determining the liquidus projection by air-cooled or water-quenched alloys, (2) constructing the 500˚C isothermal section by thermally-equilibrated alloys, (3) locating the homogeneity range of the cubic I-V-VI2 phase, and (4) measuring the thermoelectric property of ternary Ag-Bi-Se and quaternary Ag-Bi-Se-Ge alloys. Metallographic observations upon the quenched or thermally-equilibrated
ternary alloys are conducted using SEM while the phase identifications and compositional analysis are carried out by XRD and EDS, respectively.

目錄
致謝 i
摘要 ii
Abstract iii
圖目錄 vi
表目錄 xi
目錄 xii
一、 前言 1
二、文獻回顧 6
2.1相圖 6
2.1-1 Ag-Bi二元系統相平衡圖 6
2.1-2 Ag-Se 二元系統相平衡圖 6
2.1-3 Bi-Se二元系統相平衡圖 7
2.1-4 Ge-Se二元系統相平衡圖 7
2.1-5 Ag-Ge二元系統相平衡圖 8
2.1-6 Ag2Se-Bi2Se3 三元系統等值剖面圖 8
2.1-7 Ag2Se-BiSe 三元系統等值剖面圖 8
2.1-7 Ag-Bi2Se3 三元系統等值剖面圖 8
2.1-8 Ag8GeSe6-GeSe三元系統等值剖面圖 9
2.1-9 Ag2Se-GeSe2三元系統等值剖面圖 9
2.2 熱電材料 10
2.2-1 AgBiSe2熱電材料 10
三、研究方法 22
3.1 Ag-Bi-Se 三元系統相平衡 22
3.1-1 合金製備 22
3.1-2 相平衡實驗及分析 22
3.2 Ag-Bi-Se三元系統液相線投影圖 23
3.2-1 液相線投影圖合金製備 23
3.2-2 液相線投影圖合金分析 24
3.2-3 微熱差分析 24
3.3 熱電性質 25
四、結果與討論 26
4.1 Ag-Bi-Se三元系統等溫橫截面圖 26
4.1-1 Liquid+ Ag2Se 兩相區 32
4.1-2 Liquid+ AgBiSe2兩相區 38
4.1-3 Ag2Se+AgBiSe2兩相區 46
4.1-4 Liquid+AgBiSe2+Ag2Se 三相區 48
4.1-5 Ag+Ag2Se+Liquid 三相區 57
4.1-6 BiSe+Liquid+AgBiSe2三相區 58
4.1-7 Bi2Se3+ Liquid+AgBiSe2三相區 60
4.2 Ag-Bi-Se 三元系統液相線投影圖 62
4.2-1 首要析出相:Ag2Se 66
4.2-2 首要析出相:AgBiSe2 73
4.2-3 首要析出相:Ag 81
4.2-4 首要析出相:Se 82
4.2-5 首要析出相:Bi2Se3 86
4.2-6 首要析出相:Bi4Se5 89
4.2-7 首要析出相:BiSe: 90
4.2-8 首要析出相:Bi3Se2 92
4.2-9 首要析出相:Bi 93
4.3 熱電性質 94
4.3-1 AgBiSe2之熱電性質 96
4.3-1-1 AgBiSe2-Bi2Se3之熱電性質 96
4.3-1-2 AgBiSe2-Bi4Se5之熱電性質 103
4.3-1-3 AgBiSe2-Ag2Se之熱電性質 109
4.3-2 AgBiSe2-GeSe之熱電性質 117
五、結論 125
5.1 相圖 125
5.2 熱電性質 126
六、參考文獻 127

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