铜模喷铸法制备cu-ge-te热电材料的研究

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1、武汉理工大学硕士学位论文晶度样品的Seebeck系数随温度的升高而逐渐降低，而高结晶度样品呈相反变化趋势。室温下，样品功率因子随结晶度的增大而先增大后减小，当结晶度处于20％'--30％范围时材料获得较优的功率因子。448K热处理2h的样品，结晶度约25％，在400K取得最大功率因子为O．11mW．mq．K。2，热电优值Z丁约为0．17。关键词：Cu-Ge．Tc，铜模喷铸法，非晶晶化，热电性能Ⅱ武汉理工大学硕士学位论文ABSTRACTGe-Tebasedamorphousmaterialsareonetypeof“Phonon-Glas

2、s’’materialsthatpossessexcellentthermalstabilityatroomtemperature，ultrahighSeebeckcoefficient(>600p．VK"1)，extremelylowthermalconductivity(-0．1Wm。1K。1)，aswellaslowelectricalconductivity(1essthanonethousandthofthatofpromisingthermoelectricmaterialssuchasBi2Te3)．Thewaytoenh

3、ancetheelectricalconductivitywhilemaintaintheirhighSeebeckcoefficientandlowthermalconductivitybecomesthefocusedtopicinthermoelectricresearchfield．Moreover,bulkGe-TebasedamorphousmaterialsWasusuallypreparedbymelt—quenchingtechniquethathasfeaturesoftime-consumingintheheati

4、ngperiod，limitedcoolingrateandSOon,thusitisofgreatimportancetoexploreasimpleandfastpreparationrouteforsynthesizingbulkGe-Tebasedamorphousmaterials．Basedonthepresentproblemsintheresearch,inthispaper,CudopedCuxGelsTes5-x(x=5，7．5and10)basedamorphousbulkmaterialsWaspreparedb

5、yspray-castingmethodbyusingaCumold，thentheinfluenceofCuamountandtheprocessofspray—castingonthephasecomposition，microstructure，glass—formingabilityandelectricpropertieswereinvestigated．Inaddition,weresearchedthermoelectricpropertiesofsamples谢tlldifferentdegreeofcrystalliz

6、ationwhichWasadjustedbyheattreatment，anddeterminedthebestrangeofdegreeofcrystallizationinwhichsamplespossessedoptimumthermoelectricperformances．Themainresearchworkandtheresultswerelistedbelow：Resultsindicated，thespray-castingmethodcouldbeusedtofastpreparebulkCuxGel5Tes5．

7、x(x=5，7．5and10)amorphous晰tllregularshape，andwefoundCuadditioncouldincreasethecrystal-formingability．ThesizeoftheCumoldhadasignificantimpactonthecrystal·formingabilityofsamples：fortheones、析msamedepth,increasingthecrosssectionwouldcauseareducedcoolingrateandanenhancedabili

8、tyofformingcrystals；thebottomsectionofthemoldhadthehighestcoolingrateandlowestcrystal—formingability,co