No.4（2001）2.Mechanism of surface hardening on dual ion implanted metals

Shohei TANIGUCHI, Akiharu KITAHARA, Shuichi WAKAYAMA, Eiko ERIGUCHI and Naoki SUYAMA

The dual implantation of silicon and carbon ions into copper, iron and SKD11 were carried out with a MeV ion accelerator. Analysis by transmission electron microscopy revealed that the ion implanted layer of a Cu substrate is crystalline, while that of an Fe substrate is amorphous. The hardness was measured as a function of the depth by a continuous stiffness measurement method with a nano indenter. Dual ion implantation was found to enhance the hardness of a substrate, and the peak hardness occurred at a smaller depth than the peak concentration of the implanted layer. Cross-sectional transmission electron microscope images of ion implanted layers, taken under the indentations with various depth, showed that the indenter did not fracture the implanted layer, but rather deformed it plastically. These data provide us with a qualitative understanding of the hardening mechanism.

Keywords
Dual ion-implantation, Si ion, C ion, SiC, TEM, FIB, Nano-indentation

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