Surface Nanofeatures Induced by High-Energy Heavy Ions Irradiation

During neutron, ions or electron irradiation of materials, the surface morphology can be microroughened in different forms. Using a tandem accelerator with high current capability, 3.66 MeV Ni and Al ions were implanted into Ni-22at%Si alloy at 650°C and into a-Al₂O₃ at 1000°C, respectively. Scanning electron microscopy observation revealed surface nanofeatures induced by the irradiations. On the Ni-Si alloy, long parallel channels are formed having a periodicity near to 2 μm and a mean depth of 30 nm (atomic force microscopy measurements). On α-Al ₂O₃ nanopyramides with around 50 nm basis length and similar height were detected on some grains forming periodic chains. We assume that preferential sputtering produced both induced surface features.