Ni-rich Ni-Ti alloy thin films were fabricated by radio frequency (RF)-direct-current (DC) magnetron sputtering using elemental Ni and Ti as sputter targets. Si (100) was chosen as a substrate that was either held at room temperature or at 573 K (300 °C) during the depositions. The 380-nm-thick films were characterized by field emission scanning electron microscopy, energy dispersive spectroscopy, grazing incidence X-ray diffraction, atomic force microscopy, high-resolution transmission electron microscopy, and Vickers microhardness tester. The results suggests that because of the lack of surface mobility of the adatoms at the room temperature, the deposited films were smooth and amorphous, with a crystallite size of 15 nm accompanied with a porous morphology. At higher substrate temperatures, an increase in the surface diffusion leads to the formation of partially crystalline, rougher films with a denser, compact, fibrous grain microstructure. The formation of Ni-rich precipitates such as Ni4Ti3, Ni2Ti, and Ni3Ti along with small amount of the NiTi phase were attributed to the localized heating and cooling within the grains. Few grains exhibited band structures that are believed to be a result of type II twins.
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机译：以元素Ni和Ti为溅射靶，通过射频（RF）-直流（DC）磁控溅射法制备了富Ni-Ti合金薄膜。选择Si（100）作为沉积期间保持在室温或573 K（300°C）的衬底。 380纳米厚的薄膜通过场发射扫描电子显微镜，能量色散光谱，掠入射X射线衍射，原子力显微镜，高分辨率透射电子显微镜和维氏显微硬度计进行了表征。结果表明，由于室温下吸附原子缺乏表面迁移性，沉积的薄膜是光滑无定形的，微晶尺寸为15 nm，并具有多孔形态。在较高的基材温度下，表面扩散的增加会导致形成部分结晶，较粗糙的薄膜，并具有致密，致密的纤维状晶粒微结构。 Ni 4 Ti 3 ，Ni 2 Ti和Ni 3 Ti等富镍沉淀物的形成少量的NiTi相归因于晶粒内的局部加热和冷却。几乎没有晶粒显示出据认为是II型孪晶的结果的能带结构。
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