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首页> 外文会议>Space Technology amp; Applications International Forum (STAIF-99) ptol January 31-February 4, 1999, Albuquerque Hyatt Hotel, NM >An analysis on diffusion of rhemium n poco graphite at 1373 K
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An analysis on diffusion of rhemium n poco graphite at 1373 K

机译：铑n poco石墨在1373 K处的扩散分析

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Diffusion is one of the major concerns for materials operating at high temperatures. Grap[hite is being considered as the prime candidate material for a receiver-absorber-concerter used in Integrated Solar Upper Stage (ISUS). One of the anicipated problems is the loss of graphite at high temperatures. Rhemnium has been proposed a a diffusion barrier for graphite to prevent excessive loss of the material. The dissusion of rhenium an granitie is not well understood. A technique to study the diffusion of rehnium in graphite was development based on the Rutherford Backscattering Spectroscopy (RBS) technique. The graphite samples used in this experiment were Pco graphite purchased from unocal. The sample coated with rhenium was given a diffusion anneal at a temperature of 13737 K in a vacuum electron beam furnace. The diffusion profles were determined byexamining the energy distribution of backscattered helium ions. It is therefore necessary to convert the RBS spectra into concentration proflies. RUMP (Rutherford Universal Manipulation Program) is a commercially available computer prgram which is limited to thin films with thicknesses of approximately 300 nm. When the thickness of the thin film is greater than 300 nm, RUMP simulated spectra differ significantly from the exper8imental data and it is not suitable for our diffusion study which requuires thicker rhenium films. This limitation is posible due to the incorrect approximation for the energy loss cacluation. A new algorithm for interpreting RBS spectra was developed by comparing the calculated spectra with the experimental data. A better fit for RBS data was successfully obtained. The diffusion coefficients were obtained using the Matano method.
机译：扩散是材料在高温下工作的主要问题之一。 Grap [hite]被认为是集成太阳能高层（ISUS）中使用的接收器-吸收器-音乐会的主要候选材料。问题之一是高温下石墨的损失。提出了一种用于石墨的扩散阻挡层，以防止材料的过度损失。 gran和花岗岩的使用尚不十分清楚。基于卢瑟福背散射光谱（RBS）技术的一种研究to在石墨中扩散的技术已经开发出来。本实验中使用的石墨样品是从Unocal购买的Pco石墨。在真空电子束炉中在13737 K的温度下对涂有temperature的样品进行扩散退火。通过检查反向散射氦离子的能量分布来确定扩散分布。因此有必要将RBS光谱转换为浓度分布。 RUMP（卢瑟福通用操纵程序）是一种可商购的计算机程序，它仅限于厚度约为300 nm的薄膜。当薄膜的厚度大于300 nm时，RUMP模拟光谱与实验数据有显着差异，不适用于需要较厚thick膜的扩散研究。由于能量损失计算的不正确近似，因此可能出现此限制。通过将计算的光谱与实验数据进行比较，开发了一种新的解释RBS光谱的算法。成功获得了对RBS数据的更好拟合。使用Matano方法获得扩散系数。

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