Huxtable Scott, Cahill David G, Fauconnier Vincent, White Jeffrey O, Zhao Ji-Cheng
Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
Nat Mater. 2004 May;3(5):298-301. doi: 10.1038/nmat1114. Epub 2004 Apr 4.
Combinatorial methods offer an efficient approach for the development of new materials. Methods for generating combinatorial samples of materials, and methods for characterizing local composition and structure by electron microprobe analysis and electron-backscatter diffraction are relatively well developed. But a key component for combinatorial studies of materials is high-spatial-resolution measurements of the property of interest, for example, the magnetic, optical, electrical, mechanical or thermal properties of each phase, composition or processing condition. Advances in the experimental methods used for mapping these properties will have a significant impact on materials science and engineering. Here we show how time-domain thermoreflectance can be used to image the thermal conductivity of the cross-section of a Nb-Ti-Cr-Si diffusion multiple, and thereby demonstrate rapid and quantitative measurements of thermal transport properties for combinatorial studies of materials. The lateral spatial resolution of the technique is 3.4 microm, and the time required to measure a 100 x 100 pixel image is approximately 1 h. The thermal conductivity of TiCr(2) decreases by a factor of two in crossing from the near-stoichiometric side of the phase to the Ti-rich side; and the conductivity of (Ti,Nb)(3)Si shows a strong dependence on crystalline orientation.
组合方法为新型材料的开发提供了一种高效途径。生成材料组合样品的方法，以及通过电子微探针分析和电子背散射衍射来表征局部成分和结构的方法已经相对成熟。但是材料组合研究的一个关键要素是对感兴趣的特性进行高空间分辨率测量，例如，每一相、成分或加工条件的磁、光、电、机械或热性能。用于绘制这些特性的实验方法的进展将对材料科学与工程产生重大影响。在此，我们展示了如何利用时域热反射来成像Nb-Ti-Cr-Si扩散多晶体横截面的热导率，从而证明了用于材料组合研究的热输运特性的快速定量测量。该技术的横向空间分辨率为3.4微米，测量一幅100×100像素图像所需的时间约为1小时。TiCr₂从相的近化学计量比一侧过渡到富钛一侧时，其热导率降低了一半；(Ti,Nb)₃Si的电导率对晶体取向有很强的依赖性。
