快速凝固法制备ZrNiSn基Half-Heusler热电材料的微结构  

Microstructure of ZrNiSn-base Half-Heusler Thermoelectric Materials Prepared by Melt-spinning

作　　者：蔚翠[1] 朱铁军[1] 肖凯[1] 金吉[1] 沈俊杰[1] 杨胜辉[1] 赵新兵[1] 

机构地区：[1]浙江大学材料系硅材料国家重点实验室,杭州310027

出　　处：《无机材料学报》2010年第6期569-572,共4页Journal of Inorganic Materials

基　　金：国家基础研究项目(2007CB607502);国家"863"研究计划(2007AA03Z234);国家自然科学基金(50731006);教育部博士点基金(20060335126)

摘　　要：通过悬浮熔炼的方法制备了half-Heusler热电材料Zr(Hf)NiSn(Sb)合金,并进一步通过快速凝固来细化晶粒,通过放电等离子烧结制备块材并测试其热电性能.X射线衍射分析表明获得了单相Half-Heusler化合物.扫描电子显微观察发现,快速凝固后的样品晶粒尺寸在500nm左右,放电等离子烧结后晶粒尺寸并未明显长大.同时观察到在晶粒的表面还分布了很多几十纳米尺寸的小晶粒.快速凝固的样品与熔炼样品相比具有较高的电导率及载流子浓度,据此推断在快速凝固过程中产生的纳米晶粒应为金属相.快速凝固后的样品晶界散射增多,因而具有较低的晶格热导率.Thermoelectric materials Zr（Hf）NiSn（Sb） alloys were prepared by levitation melting followed by melt-spinning to refine the microstructure,and then consolidated by spark plasma sintering for the property measurements.XRD analysis showed that the half-Heusler phases were obtained.The microstructures of the melt spun thin ribbons were studied by the scanning electron microscope and transmission electron microscope.The thin ribbons were in the size of a few hundreds nanometers which didn＇t grow too much during the sintering process.Nanocrystals were found in the crystal grains.The carrier concentration increased for the melt-spinning samples compared with the levitation melting samples,indicating that the nanocrystals were metallic.The increasing boundary scattering after melt-spinning made the lattice thermal conductivity decrease.

关 键 词：ZRNISN 快速凝固 晶粒尺寸 微结构 

分 类 号：TB381[一般工业技术—材料科学与工程]