Cratering behavior in single- and poly-crystalline copper irradiated by an intense pulsed ion beam

• Published in: Surface & coatings technology 1998-10, Vol.108 (1-3), p.171-176
• Main Authors: Wood, B.P, Perry, A.J, Bitteker, L.J, Waganaar, W.J
• Format: Article
• Language: English
• Subjects: Cratering; Intense pulsed ion beam; Ion diode
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(98)00659-8

When treated with intense pulsed ion beams (IPIB), many materials exhibit increased wear resistance, fatigue life, and hardness. However, this treatment often results in cratering and roughening of the surface. In this work, high purity single crystal and polycrystalline copper samples were irradiated with pulses from an IPIB to determine whether this cratering is due to (1) bulk alloy content, (2) impact of anode debris, or (3) grain structure. Samples were treated with 1, 2, 5, and 10 shots at an average energy fluence per shot of 2 and 5 J/cm 2. Shots were about 400 ns in duration and consisted of a mixture of carbon, hydrogen, and oxygen ions at 300 keV. It was found that the single crystal copper cratered far less than the polycrystalline copper at the lower energy fluence. At the higher energy fluence, cratering was replaced by other forms of surface damage, and the single crystal copper sustained less damage at all but the largest number of shots. Molten debris from the Lucite anode (the ion source) was removed and redeposited on the samples with each shot. From this, we conclude that neither bulk alloy content nor anode debris impact cause cratering. Grain structure affects cratering, although the mechanism for this is not determined in this study.