Minimized thermal conductivity in highly stable thermal barrier W/ZrO2 multilayers
Minimized thermal conductivity in highly stable thermal barrier W/ZrO2 multilayers
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DOI：
10.1007/s00339-016-0405-0
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发表时间：
2016-10-01
影响因子：
2.7
通讯作者：
Krebs, Hans-Ulrich
中科院分区：
文献类型：
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作者：
Doering, Florian;Major, Anna;Krebs, Hans-Ulrich
纳米多层薄膜材料由于其大量的界面会严重阻碍声子的传播并导致其导热系数最小化而引起了人们极大的研究兴趣。当这些材料提供足够小的导热系数，并且具有很高的热稳定性时，它们将成为高温应用（如热障涂层）的可能候选材料。在本文中，我们采用脉冲激光沉积的方法，将热障材料ZrO2与W结合，制备出具有高熔点和高密度的薄多层材料。层厚度的设计使得体热导率由低ZrO2值控制，而超薄W阻挡层提供了大量的界面。通过这种声子散射，反射和平均自由程的缩短导致总体导热系数显著降低，甚至低于已经很低的ZrO2值。除此之外，x射线反射率测量显示，即使在1300 K退火后，这种多层材料也有很强的布拉格峰。这些结果确定W/ZrO2 (m)多层是理想的热稳定，低导电性材料。
Nanoscale thin-film multilayer materials are of great research interest since their large number of interfaces can strongly hinder phonon propagation and lead to a minimized thermal conductivity. When such materials provide a sufficiently small thermal conductivity and feature in addition also a high thermal stability, they would be possible candidates for high-temperature applications such as thermal barrier coatings. For this article, we have used pulsed laser deposition in order to fabricate thin multilayers out of the thermal barrier material ZrO2 in combination with W, which has both a high melting point and high density. Layer thicknesses were designed such that bulk thermal conductivity is governed by the low value of ZrO2, while ultrathin W blocking layers provide a high number of interfaces. By this phonon scattering, reflection and shortening of mean free path lead to a significant reduction in overall thermal conductivity even below the already low value of ZrO2. In addition to this, X-ray reflectivity measurements were taken showing strong Bragg peaks even after annealing such multilayers at 1300 K. Those results identify W/ZrO2 (m)ultilayers as desired thermally stable, low-conductivity materials.