Kim Donghwan, Lee Hyunsuk, Bae Joohyeon, Jeong Hyomin, Choi Byeongkeun, Nam Taehyun, Noh Jungpil
DGIST, 333, Techno Jungang-daero, Hyeongpung-myeon, Daiseong-gun, Daegu, 42988, Republic of Korea.
Department of Energy and Mechanical Engineering and Institute of Marine Industry, Gyeongsang National University, 38, Cheondaegukchi-gil, Tongyeong, Gyeongnam, 53064, Republic of Korea.
J Nanosci Nanotechnol. 2018 Sep 1;18(9):6201-6205. doi: 10.1166/jnn.2018.15636.
Ti-Ni shape memory alloy (SMA) thin films are very attractive material for industrial and medical applications such as micro-actuator, micro-sensors, and stents for blood vessels. An important property besides shape memory effect in the application of SMA thin films is the adhesion between the film and the substrate. When using thin films as micro-actuators or micro-sensors in MEMS, the film must be strongly adhered to the substrate. On the other hand, when using SMA thin films in medical devices such as stents, the deposited alloy thin film must be easily separable from the substrate for efficient processing. In this study, we investigated the effect of substrate roughness on the adhesion of Ti-Ni SMA thin films, as well as the structural properties and phase-transformation behavior of the fabricated films. Ti-Ni SMA thin films were deposited onto etched glass substrates with magnetron sputtering. Radio frequency plasma was used for etching the substrate. The adhesion properties were investigated through progressive scratch test. Structural properties of the films were determined via Feld emission scanning electron microscopy, X-ray diffraction measurements (XRD) and Energy-dispersive X-ray spectroscopy analysis. Phase transformation behaviors were observed with differential scanning calorimetry and low temperature-XRD. Ti-Ni SMA thin film deposited onto rough substrate provides higher adhesive strength than smooth substrate. However the roughness of the substrate has no influence on the growth and crystallization of the Ti-Ni SMA thin films.
钛镍形状记忆合金（SMA）薄膜对于微致动器、微传感器和血管支架等工业和医疗应用来说是极具吸引力的材料。在SMA薄膜应用中，除形状记忆效应外，一个重要特性是薄膜与衬底之间的附着力。在微机电系统（MEMS）中，当使用薄膜作为微致动器或微传感器时，薄膜必须牢固地附着在衬底上。另一方面，在诸如支架等医疗设备中使用SMA薄膜时，沉积的合金薄膜必须易于从衬底上分离以便进行高效加工。在本研究中，我们研究了衬底粗糙度对钛镍SMA薄膜附着力的影响，以及所制备薄膜的结构特性和相变行为。通过磁控溅射将钛镍SMA薄膜沉积在蚀刻后的玻璃衬底上。使用射频等离子体对衬底进行蚀刻。通过渐进式划痕试验研究附着力特性。通过场发射扫描电子显微镜、X射线衍射测量（XRD）和能量色散X射线光谱分析来确定薄膜的结构特性。用差示扫描量热法和低温XRD观察相变行为。沉积在粗糙衬底上的钛镍SMA薄膜比光滑衬底具有更高的附着力。然而，衬底的粗糙度对钛镍SMA薄膜的生长和结晶没有影响。
