Tracer Diffusion Data for Metals, Alloys, and Simple Oxides
Tracer Diffusion Data for Metals, Alloys, and Simple Oxides
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DOI：
10.1007/978-1-4684-6075-9
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发表时间：
1970-03
期刊：
影响因子：
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通讯作者：
J. Askill
中科院分区：
文献类型：
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作者：
J. Askill
原子在金属中的扩散最早是在大约65年前被发现的，从那时起，关于各种系统中的扩散的数据已经积累了相当丰富的数据。然而，大约在1940年以前的工作现在主要是有历史意义的，因为实验通常是在实验条件下进行的，分析方法导致在解释测量的扩散系数时存在不确定性。有关扩散速度的数据在由原子迁移速度控制的过程中非常重要，例如相的生长和合金的均化。此外，扩散在氧化、塑性变形、烧结和蠕变等现象的理论中也起着重要的作用。第二次世界大战后，由于具有足够高比活度的放射性同位素的出现，扩散研究取得了巨大的进步。然后，使用与溶剂材料具有相同化学性质的放射性同位素测量自扩散速率成为可能，并且当杂质浓度很小而不改变体系的化学均一性时，也可以研究示踪杂质扩散。在过去的十到十五年中，用于扩散研究的材料的纯度有了明显的提高，分析方法也变得更加标准化。
Atomic diffusion in metals was first discovered some sixty-five years ago, and since then a considerable wealth of data has ac cumulated on diffusion in various systems. However, work prior to about the year 1940 is now mainly of historical interest, since ex periments were often carried out under experimental conditions and with methods of analysis leading to uncertainties in inter preting the measured diffusion coefficients. Data on diffusion rates are of importance in processes which are controlled by rates of atomic migration such as growth of phases and homogenization of alloys. In addition diffusion plays an important part in theories of such phenomena as oxidation, plastic deformation, sintering, and creep. A tremendous advance in diffusion studies was made possible by the availability of radioactive isotopes of sufficiently high spe cific activity after the second world war. Measurements of self diffusion rates then became possible using radioactive isotopes having the same chemical properties as the solvent material, and it also became possible to study tracer impurity diffusion when the concentration of the impurity is so small as not to alter the chemi cal homogeneity of the system. In the last ten to fifteen years the purity of materials used in diffusion studies has increased con siderably and the methods of analysis have become more stand ardized.