Improving the properties of metallic materials by surface alloying induced with a pulsed electron beam

摘要

Surface alloying of metallic materials implemented by a liquid-phase mixing of thin deposited film with upper layer of substrate using a low-energy, high-current electron beam (LEHCEB) has been investigated. In surface alloying, LEHCEB has been employed as a source of energy that is delivered to the near-surface layer of the workpiece and released there. The electron-beam parameters were: 2–3 µs pulse duration and 30 keV maximum electron energy. Deposition of metallic films was performed by means of magnetron sputtering. Systems of metals examined were Zr-Ti, Ni-Cu as well as Stainless Steel deposited on Cu substrate. Investigation of cross-section of the samples revealed that concentration of the substrate material changes gradually from 100 in the bulk to almost 0% at the surface. In contrast, the concentration of the alloyed material changes from 0 in the bulk to about 100% at the surface. In such a way the composition of formed surface alloy represents two different metallic materials bonded via a transition layer. Investigations of properties of Cu electrodes alloyed by Ni showed in particularly that they reveal improved electric strength of vacuum insulation compared to that for the initial and LEHCEB-irradiated electrodes made of pure copper.