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周小卫,刘珍光,王宇鑫,沈以赴.超声振荡频率对电沉积纳米晶Ni微织构生长和抗磨性的关联性研究[J].稀有金属材料与工程(英文),2019,48(12):3978~3989.[Zhou Xiaowei,Liu Zhengguang,Wang Yuxin and Shen Yifu.Influence of Ultrasound with Varying Frequencies on Microstructures and Wear Resistance for Ni Nanocrystals[J].Rare Metal Materials and Engineering,2019,48(12):3978~3989.]
Influence of Ultrasound with Varying Frequencies on Microstructures and Wear Resistance for Ni Nanocrystals
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Received:September 16, 2018  Revised:December 06, 2018
DOI:
Key words: ultrasonic frequency  Ni nanocrystals  porous Ti  growth textures  wear resistance
Foundation item:国家自然科学基金资助(项目号51605203);江苏省自然科学基金资助(项目号BK20150467)
Author NameAffiliation
Zhou Xiaowei,Liu Zhengguang,Wang Yuxin and Shen Yifu  
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Abstract:
      Because of its light weight, high strength and excellent corrosion resistance, titanium and its alloys have been currently used as a brand-new functional material in ships, aviation and other fields. However, it yet exists some defects such as poor surface weldability and wear resistance, especially under the dry-sliding conditions without solid lubricants, so it is essential to enhance its surface properties using surface modification techniques. Herein, this study focused on surface electroplating of nanocrystalline Ni coating on the anodized nanoporous surface of Ti substrate, as well as to achieve a metallurgical bonding interface. In view of this, the objectives of this study are to explore the detailed correlation between growth textures and wear resistance of Ni deposits by means of adjusting ultrasonic frequencies (shorted as “UF”) values. The textural directions and microstructures of the as-deposited Ni nanocrystals were characterized using XRD, FE-SEM and TEM. According to Nanoindentation and wear tests, the synergistic effects from ultrasonic oscillations on both grain refinement and crystallographic texture of Ni nanocrystals were evaluated. Besides the underlying mechanism involved in effects by ultrasonic oscillation on dynamic re-crystallization of Ni textures during the electroplating process, and the relationship between different textural directions of Ni crystals and surface properties were disclosed. The survey results manifested that the pre-adsorbed Pd atoms onto the as-anodized porous Ti surface were acted as nucleation sites for inducing the subsequent Ni growth, having an effective interfacial strength of Ti/Ni composites. Based on Nanoindentation results, it significantly improved its surface toughness by depositing Ni coatings onto the as-anodized Ti matrix, and the hardness and elastic modulus reached 15.6 and 197.2 GPa. Meanwhile its friction coefficient of Ti matrix within Ni coating at UF values of 45+80kHz was much lower, which was reduced by about 2 times relative to that of bare Ti matrix. Ultimately, the wear mechanism was transformed from the originally cutting wear behavior of Ti matrix into the sightly adhesive wear together with grinding abrasion for Ni deposits, effectively compensating the shortcomings of poor wear resistance for Ti alloys used in engineering applications.