J0404-2-4 形状記憶合金上に作製した金属を含有する非晶質炭素膜の疲労強度評価([J0404-2]知的材料・構造システム(2):新機能材料II)

概要

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NiTi shape memory alloy (SMA) is expected as medical devises utilizing the shape memory effect. However, release of the Ni ions from the TiNi SMA into the human body is one of the critical issues because Ni ions induce allergetic reaction. Diamond-like carbon (DLC) coating is one of the expected materials that can prevent the release and reaction of such ions. Fatigue strength to endure cyclic bending of the SMA substrate is required to use DLC as coating materials onto NiTi. Although conventional DLC coating is very brittle and has a week adhesive strength on metallic substrate, the way of addition metal into a DLC matrix is one of the possibilities to achieve good adhesiveness and bending flexibility. In this study, the fatigue strength of tungsten-containing DLC coating on SMA plate was investigated. DLC was deposited on a SMA plate by radio-frequency chemical vapor deposition (RFCVD) and also co-sputtering of metal target. The fatigue strength of DLC has been characterized by applying 1% shape memory deformation. In the result, no cracks and interface delamination were observed up to 10^4 cycles.
2010-09-04