Electrolytic Deposition of Ni/NiO on Stainless Steel for Production of Selective Surfaces

Abstract The solar energy is one of the most promising energy sources today. In this context, the goal of this work is to produce selective surfaces for receiver tubes of parabolic trough collectors (PTCs). Ideally, solar collectors should have an absorbing surface that has high absorptance for radiation in the solar energy spectrum and, at the same time, low emittance. Therefore, Ni/NiO selective surfaces were produced with Ni in the first film and NiO in the second film. The method used was by electrolytic deposition of nickel on stainless steel AISI 304, followed by oxidation in a muffle furnace. The thicknesses of the coatings were measured with the photometer Digimess, making it possible to verify their variations and the surface irregularities typical of the electrodeposition procedure. The NiO film was observed in scanning electron microscope (SEM). The film hardness was evaluated by the pencil hardness test and the adhesion by the tape test.摘要 太阳能是当今最具发展潜力的能源之一。在此背景下，本研究的目标是为抛物槽式集热器（parabolic trough collectors，PTCs）的接收管制备选择性吸光表面。理想状态下，太阳能集热器的吸光表面应在太阳能光谱范围内对辐射具备高吸收率，同时拥有低发射率。据此，本研究制备了Ni/NiO型选择性吸光表面，第一层薄膜为金属镍，第二层薄膜为氧化镍。本研究采用的制备工艺为：先在AISI 304不锈钢基底上电沉积镍，随后将试样置于马弗炉中进行氧化处理。采用Digimess型光度计测量涂层厚度，以此验证涂层厚度的变化情况以及电沉积工艺典型的表面不平整特征。通过扫描电子显微镜（scanning electron microscope，SEM）观测了氧化镍薄膜的微观形貌。通过铅笔硬度测试评估薄膜的硬度，并采用胶带测试法表征其附着性能。