Anodized porous titanium coated with Ni-CeO 2 deposits for enhancing surface toughness and wear resistance
Anodized porous titanium coated with Ni-CeO 2 deposits for enhancing surface toughness and wear resistance
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DOI：
10.1016/j.apsusc.2017.02.034
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发表时间：
2017-05
影响因子：
6.7
通讯作者：
Xiaowei Zhou;C. Ouyang
中科院分区：
文献类型：
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作者：
Xiaowei Zhou;C. Ouyang
为了大幅度提高纯钛（Ti）表面的韧性和耐磨性，在具有纳米孔结构的阳极氧化钛（ATO）表面制备了Ni-CeO 2纳米复合涂层。针对Ti表面TiO 2阻挡层抑制其电化学活性的问题，采用阳极氧化、敏化、活化等预处理工艺，然后化学镀Ni-P膜作为Ni-CeO 2镀层的活化层。ATO纳米孔周围存在的Pd原子有望作为支撑化学镀Ni-P薄膜生长位置的异质形核位点。介绍了采用多孔结构结合针孔的界面设计创新，以实现钛基体与表面涂层之间的冶金结合界面。此外，本文还研究了CeO 2纳米粒子对Ni-CeO 2纳米复合镀层的微观结构和磨损机理的影响。采用XRD、FE-SEM、TEM和纳米压痕等测试手段，比较了Ni-CeO 2涂层与纯镍的磨损行为。结果表明，采用磷酸盐型阳极氧化液，在直流150 V下可获得平均直径约为200 nm、分布均匀的钛纳米孔。TAO表面沉积Ni-CeO 2后，其磨损表面无疲劳裂纹，表明存在的富Ce磨损产物可作为固体润滑相，对脱层失效起到自修复作用。更重要的是，这一发现将指导富铈沉淀有望作为强化相的阳极氧化多孔钛，铝和镁合金，以强化其表面性能。
In order to make large improvements of surface toughness and wear resistance for pure titanium (Ti) substrate, anodic titanium oxide (ATO) surface with nanoporous structure was coated with the Ni-CeO2nanocomposite coatings. Regarding TiO2barrier layer on Ti surface to inhibit its electrochemical activity, pre-treatments were successively processed with anodizing, sensitizing, activating, and then followed by electroless Ni-P film to be acted as an activated layer for electroplating Ni-CeO2deposits. The existing Pd atoms around ATO nanopores were expected as the heterogeneous nucleation sites for supporting the growing locations of electroless Ni-P film. The innovative of interface design using porous structure was introduced for bonding pinholes to achieve a metallurgical adhesion interface between Ti substrate and surface coatings. Besides the objectives of this work were to elucidate how effects by the adding CeO2nanoparticles on modifying microstructures and wear mechanisms of Ni-CeO2nanocomposite coatings. Many efforts of XRD, FE-SEM, TEM and Nanoindentation tests were devoted to comparing different wear behaviors of Ni-CeO2coatings relative to pure nickel. Results indicated that uniform-distributed Ti nanopores with an average diameter size of ∼200 nm was achieved using the Phosphate-type anodizing solution at DC 150 V. A worn surface without fatigue cracks was observed for TAO surface coated with Ni-CeO2deposits, showing the existing Ce-rich worn products to be acted as a solid lubricant phase for making a self-healing effect on de-lamination failures. More important, this finding will be the guidelines for Ce-rich precipitations to be expected as the strengthening phase in anodized porous of Ti, Al and Mg alloys for intensifying their surface properties.