J0203-2-5 医療機器への応用を想定したNiTi形状記憶合金への金属含有DLC膜の作製とその疲労強度評価(医療診断のためのマルチスケール血流動態計測と解析(2))

Abstract

NiTi shape memory alloys (SMAs) are widely used for medical devises utilizing a shape memory effect. However, release of the Ni ions from SMA into a human body is one of the significant issues to be solved because Ni ions cause the allergenic reaction. Diamond-like carbon (DLC) coating is one of the promising materials that can prevent the release of such ions. To use DLC as coating materials, fatigue strength to endure cyclic bending of the SMA substrate is required. Although conventional DLC coating is very brittle and show weak adhesive strength to metallic substrate, the addition of metal into a DLC matrix has the potential to show good adhesiveness and bending flexibility. In this study, fatigue strength of tungsten-containing DLC coating on a SMA plate was investigated. DLC was deposited on a SMA plate by radio-frequency chemical vapor deposition method and also co-sputtering of a metal target. Fatigue strength of the coatings has been characterized by applying 1% cyclic bending strain. Coated surfaces were observed after bending test using an optical microscope and a scanning electron microscope.