金属及合金中射程参数的研究SCIEI

本文应用金属中Wigner-Sietz(W-S)半径数据和引入等效电荷概念,结合Ziegler的质子注入数据,导出了计算重离子注入各种金属中的电子阻止本领S_c(E)的公式,计算结果与文献中的实测值结果甚为一致。同样,应用合金中的W-S半径,导出了适用于合金硼化物和CsCl型合金的S_c(E)计算公式。计算结果表明,公式对单硼或二硼化合物符合得较好,而对一些复杂结构的合金以及Cr_5B_3和W_2B_5是不适合的。对CsCl型合金,S_c(E)对Bragg定律的偏离系数γ和合金中电荷转移量成正比,后者越大表明金属键越强,则合金对离子的阻止本领越大,这与实验结果是吻合的。合金中两元素在同一周期中位置相差越远,这种趋势越明显。不同周期元素组成的合金更加强了这种趋势。

INVESTIGATION OF RANGE PARAMETERS IN METAL AND ALLOY

The formulas to calculate the electronic stopping power, S_c(E), forheavy ion implanting into metal have been developed by using the Wigner-Sietz ra-dius, equivaleni charge, Fermi velocity and Ziegler's values of hydrogen electronicstopping power. The results calculated are believed to be in agreement with thosemeasured experimentally in previous literature. The formulas to evaluate S_c(E) foralloy, boride containing or CsCl structure have been also derived. However, theseare favourable to only mono-or bi-borides, but not for borides with complex struc-ture such as Cr_5B_3 or W_2B_5. The coefficient of S_c(E) for alloy of CsCl structuredeviating from Bragg's S_c(E) is directly proportional to charge transfer in alloy.The larger the charge transferis, the stronger the metallic bond is. Hence, theS_c(E) created by metallic bond in alloy will be increased; there is a tendency forit to increase with increasing separation of two components in alloy on either sideof Cr group at same periods; and the tendency is larger when the two componentsare in different periods.